abstract
DESCRIPTION
3464TRANSCRIPT
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1.01
THINkS: A Novel Tool for M ultiscale CFD Calculations of
Human Blood Circulation
Dr. P. George Huang Professor and Chair
Department of Mechanical and Materials Engineering
Wright State University
Dayton, OH 45435
Ph: +1 937 775 5043; Email: [email protected]
Abstract
Computational Fluid Dynamics (CFD) is emerging as a tool for better assessment and management of cerebral
aneurysms. CFD calculations are often restricted to a small arterial zone and the solution is sensitive to boundary
conditions prescribed. A 1D simulation of the complete vessel network, THINkS (Total Human Intravascular NetworK
Simulation), is introduced to better describe the boundary conditions and to provide an overall flow information of the
complex vessel network.
As the governing equations for the blood flow in human vessel system can be casted in the same form as the gas dynamic
equations, the traditional shock capturing scheme can be modified to solve the hemodynamic equations. In this talk
we will discuss an in-house computer program - THINkS. THINkS consists of a simulation of 85 major arteries, 158
major veins, 43 arterial and 77 venous junctions. Blood flow in arterioles, capillaries and venules is modeled using
lumped parameter models, or the 0D models, which are modeled using the connection of a number of capacitors,
resistors and inductors to represent the real physics. The model used a simple 0D model for 20 one-artery-to-one-vein
micro circulations and 4 other 0D models for 7 complex arteries-to-veins micro circulations. Moreover, a 4-chamber 0D
model for the heart is used to allow blood to pump from superior vena cava I and inferior vena cava I veins, through
the pulmonary system, and discharge back to the ascending aorta artery. In addition to the 4 valves inside the heart,
there are also 15 venous valves used in the venous system.
THINkS calculations indicated usefulness of the model in predicting the trends of cerebral flow patterns. THINkS
solutions were validated with a number of in vivo experimental data and the agreement was excellent. A comparison
with experiments for the impact of incomplete circle of Willis (CoW) to the flow patterns was also made and the trend
shows an excellent agreement with reported data. THINkS allows for more accurate boundary conditions for 3D zonal-
based CFD calculations. THINkS has been validated against available experimental data and shown to respond correctly
to the flow pattern change caused by the variation in CoW. It provides the detailed flow information of the entire
human body including cerebral vessel network. Our aim is to use THINkS to generate accurate flow assessments, guide
treatment plans, and more reliably predict risks associated with vascular lesions.
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1.02
M easurement and Observation of Elementary Transition Boiling
Process after Sudden Contact of Liquid with Hot Surface
Yuichi MITSUTAKEa, Suhaimi ILLIASb, Koutarou TSUBAKIb,
Mohammad Nasim Hasanc, Masanori MONDEd aInstitute of Ocean Energy, Saga University, 1 Honjo-machi, Saga-shi, Saga Japan
bDepartment of Mechanical Engineering, Saga University, 1 Honjo-machi, Saga-shi, Saga Japan
cDepartment of Mechanical Engineering, Bangladesh University of Engineering & Technology, Dhaka-1000, Bangladesh
dReserch Cemeter for Hydrogen Industrial Use and Storagey,Kyusyu University, 744 Motooka,Nishi-ku, Fukuoka-shi, Fukuoka Japan
Abstract
A Fast response surface temperature measurement technique has been developed to investigate transient transition
boiling phenomena after ethanol droplet impact on a nickel hot surface. Our motivation is to make clear the mechanism
of boiling transition between nucleate and film boiling which is closely related the recovery of wetting on the hot surface
being higher than the Leidenfrost temperature. In this study transient boiling phenomena during sudden contact of an
ethanol sessile droplet on a hot solid surface has been investigated to understand what governs whether the solid surface
keeps wet or not. The droplet impact boiling system is very simple and easier to observe but it includes the elementary
transition boiling process. Since the transient transition took place within a couple ten milliseconds, observation with
high speed video system and fast response surface temperature measurement technique are essential for better
understanding of the transition boiling phenomena.
The experiments were conducted for single and multiple droplet impacts. The multiple droplet impacts simulates liquid
and solid contact situations on a hot surface during spray or laminar jet quench. The nickel disk of 50 mm in diameter
and 5 mm in thickness was used as the hot surface. The hot surface was inclined from 0 deg (horizontal) to 40 deg. The
fast-response film thermocouple with a typical minimum response time of 80 microseconds was developed and fabricated
on the nickel disk at the depth of 3 micrometers from the surface. The temperature histories just beneath the surface
were recorded at the sampling frequency of 200 kHz. The boiling phenomena beneath a sessile droplet impacted on the
hot surface were observed by using a microscope equipped with the high speed video camera at the maximum frame
rate of 22.5 kfps. The surface temperature and surface heat flux were estimated with 1D inverse heat conduction
analysis. Histories of local surface temperature and local heat flux were compared with the boiling video image. The
experiments were done for different initial wall temperatures up to 250 oC, different liquid subcoolings from 33 to 53
K. The multiple impact frequency was changed from 280 to 840 Hz.
In case of the single droplet impact tests, the observation results showed that wetting situation was maintained for very
short time even though the surface temperature was beyond the liquid superheat limit temperature. We defined the
vapor film generation time as the characteristic boiling transition time scale from wetted nucleation boiling regime to
dry film boiling regime. The film generation time were measured for the extensive initial surface temperature range,
different subcoolings and different impact velocities. As the initial surface temperature increased, the film generation
time decreased to order of microsecond and film boiling situation seemed to be established via spontaneous nucleation
(vapor explosion) process. In case of the multiple droplets impact tests, film generation times were evaluated every
droplet impact during continuous cooling from the initial solid temperature. As long as the generation time was less
than 1 millisecond and much shorter than the impact period, stable film boiling was observed. Then the film generation
time increased with the droplet impact times and approached to the droplet impact period as the cooling time elapsed.
This region was recognized as the transition boiling region. After the generation time reached to the droplet impact
period and then stable wetted situation, namely nucleate boiling was observed. As compared with the single impact
tests, the generation time for the multiple impact became shorter than that for the single droplet impact at same initial
surface temperature and the lower limit surface temperature observed vapor film generation was reduced. This fact may
imply the effect of transient heat conduction on the wetting temperature shifts to higher wall superheat temperature
beyond liquid superheat limit temperature during quenching with jets or sprays.
Keywords: Fast-response temperature measurement; Transient transition boiling; Droplet; Wetting phenomenon
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1.03
The Advanced Technology and Future Prospect of OTEC in
Japan and the World - for Stable Energy &Sustainable Water
Resource Yasuyuki Ikegami, Saga University, Japan
Abstract
Europe and America and Korea have been promoted the practical use of the marine renewable energy forward on a
large scale project by the strong leadership of these governments while an energy problem and an environmental problem
of the 21st century on a global scale have been increasing in the acuteness and emergency degrees. The renewable ocean
energy (ROE) is strongly expected worldwide at practical use to be next to photovoltaic power generation, wind power
generation as enormous energy resources and a point of the job creation.. The activity of Japan on ROE has been
evaluated as world top-level at the laboratory level, by the way, Japan is delayed in the actual large proof R&D in the
sea area in the other countries more than ten years. Recently, Japan with a few resources has begun to be aimed at the
innovation of the ROE development full-scale as the sixth useful area in world, so-called exclusive economic zone (EEZ).
This year, the NEDO announced the technical road map toward 2030 of ROE including ocean thermal energy
conversion(OTEC) and the wave power generation.
Saga University has investigated on REO as only COE on REO in the whole country. Especially, OTEC has been
researched as aim at the practical use for about 40 years. OTEC is a system generating electricity with temperature
difference between warm sea water of the ocean surface and the cold sea water from depths 600m to 1,000m. The 30kW
OTEC device which Saga University has is evaluated on as the device that performance is the highest now in the world.
The characteristic of OTEC is stable and multi-purpose, not only the electricity but also seawater water conversion,
hydrogen production, lithium collection, the fishing ground reproduction is possible. Saga university has contributed to
the development of sustainable energy and water resources that these Japanese technology is asset to the project in
U.S.A., France, India, Taiwan now In this session, the current status and future prospect are presented on ROE, mainly
on OTEC.
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1.04
CFD, In vivo and In vitro Studies for Biofluid Circulations
Dr. Ing. Suh, Sang-Ho Dept. of Mechanical Engineering, Soongsil University, Seoul, Korea
Abstract
Arterial diseases are being increased and the pathogenesis of hemodynamic mechanism of the development and
progression of vascular disorders such as atherosclerosis and aneurysm are being investigated. Development of clinical
diagnostic techniques has been so limited to define the pathobiological role of atherosclerosis. FSI (Fluid Structure
Interaction) and flow visualization is a good tool to analyze the vascular flow patterns. CFD, FSI and In vitro experiment
can helps to predict pathogenesis of the biofluid circulation problems and also applied to development of clinical
diagnostics technique. Atherosclerosis is a progressive disease characterized by inflammation and lipid accumulation in
the vascular wall, Obstructive sleep apnea (OSA) is a syndrome characterized by repetitive episodic collapse of the
upper airway, and ureter obstruction occurs when urine flows in parallel in the bore and in the surrounding annulus of
a stent. The purpose of this study is to analyze flow patterns in the left coronary artery, upper airway, and ureter using
numerical and experimental techniques. Here we analyzed flow patterns and hemodynamic factors using numerical
techniques. We analyzed FSI (Fluid Structure Interaction) simulations in the left coronary artery, upper airway, and
ureter double J-stent 3D models which were carried out from CT scanned images and meshing done by CFD. The inflow
and outflow boundary conditions were applied from CT data for flow analysis. A Navier-Stokes governing equations
were discretized by finite volume method for numerical simulations. FSI analysis were performed of left coronary artery
to get the hemodynamic factors and flow visualization done by rapid prototype model, obstructive sleep apnea performed
flow characteristics in the upper airway to emerging concepts of ventilator control mechanisms in the normal sleep
apnea versus sleep disordered breathing, and ureter obstruction flow analysis of the effects of the ureteral wall
compliance, the pressure difference between the ureteral inlet and outlet. In the coronary RP model, Youngs modulus and movement of coronary artery which affect hemodynamic and accordingly has an effect on atherosclerosis, and The
magnitude of the pressure gradient is regarded as the pressure effort required for breathing and extent the reduction of
pressure effort in the upper airway. These all results can be used to develop of clinical diagnostics techniques.
1.05
A new approach to anisotropy in wall-turbulent shear flow, and
with application to organised disturbances, when these are
present
P. K . Sen, Srinivas V. Veeravalli, S. Hegde and Ganapat i Josh i Department of Applied Mechanics, Indian Institute of Technology Delhi,
New Delhi 110-016, India
.
ABSTRACT
This paper takes a re-look at anisotropy in wall-turbulent shear flow, from the viewpoint of the primitive equations for
turbulence, i.e. without considering averages. The paper attempts to develop some simple rules for the anisotropic part,
and arrives at a logical definition of eddy viscosity and the turbulent shear stress tensor. The results are extended to
the constitutive equation for organised disturbances in turbulent shear flows, when such disturbances are present. The
model of Sen and Veeravalli (Sadhana 1998, 2000, 2007), for organised disturbances, seems to be vindicated.
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1.06
A M icro Industry with Closed Energy and Water Cycles for
Sustainable Rural Development
Padma Vasudevan Sena, P.K. Sena, S. Hegdea, S.N. Singha, A. Mukhopadhyayb,
Prahalad Singhc, Philip Daviesd, R. Berryd, P. K. Deyd and Cyrus Engineere aDepartment of Applied Mechanics, Indian Institute of Technology, Delhi, India
bDepartment of Science and Technology, Delhi, India
cSchool of Desert Sciences, Jodhpur, Rajasthan, India
dAston University, Birmingham, U.K.
eIB Turbo Limited, New Delhi, India
Abstract
Sustainable development requires combining economic viability with energy and environment conservation and ensuring
social benefits. It is conceptualized that for designing a micro industry for sustainable rural industrialization, all these
aspects should be integrated right up front. The concept includes; (a) utilization of local produce for value addition in
a cluster of villages and enhancing income of the target population; (b) use of renewable energy and total utilization of
energy generated by co and trigeneration (combining electric power production with heat utilization for heating and
cooling); (c) conservation of water and complete recycling of effluents; (d) total utilization of all wastes for achieving
closure towards a zero waste system. Enhanced economic viability and sustainability is achieved by integration of
appropriate technologies into the industrial complex.
To prove the concept, a model Micro Industrial Complex (MIC) has been set up in a semi arid desert region in Rajasthan,
India at village Malunga in Jodhpur district. A biomass powered boiler and steam turbine system is used to generate
100-200 KVA of electric power and high energy steam for heating and cooling processes downstream. The unique feature
of the equipment is a 100-150 kW back-pressure steam turbine, utilizing 3-4 tph (tonnes per hour) steam, developed by
M/s IB Turbo. The biomass boiler raises steam at about 20 barg 3 tph, which is passed through a turbine to yield
about 150 kW of electrical power. The steam let out at a back pressure of 1-3 barg has high exergy and this is passed
on as thermal energy (about 2 MW), for use in various applications depending on the local produce and resources. The
biomass fuel requirement for the boiler is 0.5-0.75 tph depending on its calorific value. In the current model, the
electricity produced is used for running an oil expeller to extract castor oil and the castor cake is used as fuel in the
boiler. The steam is used in a Multi Effect Distillation (MED) unit for drinking water production and in a Vapour
Absorption Machine (VAM) for cooling, for banana ripening application. Additional steam is available for extraction
of herbs such as mint and processing local vegetables.
In this paper, we discuss the financial and economic viability of the system and show how the energy, water and
materials are completely recycled and how the benefits are directed to the weaker sections of the community.
Keywords: Trigeneration; Micro-industry; Sustainable development.
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2.01
Experimental Study on Heat Transfer and Friction Factor in
Laminar Forced Convection over Flat Tube in Channel Flow
Tahseen Ahmad Tahseena,c, M.M. Rahmana,b,* and M. Ishaka a Faculty of Mechanical Engineering, University Malaysia Pahang
26600 Pekan, Pahang, MALAYSIA
Phone : +609-424-2246; Fax : +609-424-2202
bAutomotive Engineering Centre, Universiti Malaysia Pahang
26600 Pekan, Pahang, MALAYSIA
c Department of Mechanical Engineering, College of Engineering
Tikrit University, Tikrit, IRAQ
Abstract
The heat transfer and fluid flow over a flat tube in the channel with laminar forced convection is experimentally
investigated. The experiments were conducted at a flat tube in the flow direction, the five air velocity between 0.2
and1.0 m/s, and Reynolds number based on the hydraulic diameter (ReDh) was considered from 124.5 to 622.5. The
uniform heat flux supplies are at the surface of the tube are 354.9, 1016.3 and 1935.8 W/m2 respectively. The
experimental results indicate that the average Nusselt numbers ( ) for the flat tube increased with increase of ReDh
at fixed of the heat flux supply. The increased with an increase of heat flux supply at fixed ReDh. On the other
hand, the friction factor decreased with increases of the front free stream velocity. The relationship with ReDh in
the power law, the ReDh correlation was found to be = (). The correlation achieved good
predictions of the measured data with the minimum root mean square value is 99.70%.
Keywords: Laminar forced convection; heat transfer; fluid flow; Reynolds number; heat flux; Nusselt number.
2.02
M HD Free Convection and M ass Transfer Flow through a
Vertical Oscillatory Porous Plate with Hall, Ion -slip Currents and
Heat Source in a Rotating System
Md. Delowar Hossain, Md. Abdus Samad and Md. Mahmud Alam Department of Mathematics,University of Dhaka, Dhaka-1000, Bangladesh
*Mathematics Discipline, Khulna University, Khulna-9208, Bangladesh
Abstract
Unsteady MHD free convection and mass transfer flow through a vertical oscillatory porous plate with hall, ion-slip
currents and heat source in a rotating system are studied. The governing equations of the problem contain a system of
non-linear coupled partial differential equations. The coupled non-linear partial differential equations are solved by
explicit finite difference method and the numerical results have been calculated by Compaq Visual 6.6a. For good
accuracy, stability and convergence analysis have been analyzed. The results of this investigation are discussed for the
different values of the well-known parameters and are shown graphically.
Keywords: MHD flow, Hall current, Ion-slip current, Suction parameter, Heat source parameter.
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2.03
Two-phase frictional multiplier correlation for the prediction of
condensation pressure drop inside smooth horizontal tube
Md. Anowar Hossaina,, Hasan MM Afroza, Akio Miyarab aDepartment of Mechanical Engineering, Dhaka University of Engineering & Technology, Gazipur,
Bangladesh
bDepartment of Mechanical Engineering, Saga University, Saga shi 840-8502, Japan
Abstract
In the present work, a two-phase frictional multiplier (v) correlation for the prediction of condensation pressure drop
inside smooth horizontal tube has been proposed incorporating the effect of mass velocity, tube geometry and surface
tension. Other existing correlations and the newly proposed correlation of two-phase frictional multiplier have been used
to predict the condensation pressure drop of R1234ze(E), R32, R410A, dimethyl ether (DME) and
R1234ze(E)/R32mixtures (30/70 and 45/55 weight %) inside a horizontal smooth tube. The predicted results have been
compared with the available experimental data which is done inside a water heated double tube heat exchanger. The
test section is a horizontally installed smooth tube with effective length of 3.6m and inner diameter of 4.35mm. The
experiment has been carried out under the conditions of mass flux varying from 147 to 403 kgm-2s-1 and the saturation
temperatures ranging between 30 and 45 C, over the vapor quality range 0.0065 to 0.9724. From the results of
comparison, proposed correlation shows better performance for all refrigerants. Proposed v correlation can predict all
the experimental data within 11%.
Keywords: Condensation; R1234ze(E); frictional multiplier; R1234ze(E)/R32 mixture.
2.04
Geometric effect on magnetohydrodynamic convection in a half -
moon shaped cavity filled with water having semi-circular bottom
heater
Khan. Md. Rabbi, Towkir Ahmad, Satyajit Mojumder, Sourav Saha, Md. Zobayer
Hossain Department of Mechanical Engineering, Bangladesh University of Engineering & Technology, Dhaka-1000, Bangladesh
Abstract
Magneto-hydrodynamic convection has been gaining attention due to its wide range of application. In this paper
magneto-hydrodynamic convection in a half-moon (semi-circular) shaped cavity has been analysed. The cavity has two
semi-circular bottom heaters and effect of distance between this two heaters has been thoroughly investigated for two
different cases ( = 0.1, 0.4). Numerical simulation has been carried out for a wide range of Rayleigh number (Ra = 103 ~ 107) and for Hartmann number (Ha = 0 ~ 100) to understand the flow and thermal field. Galerkin weighted
residual method of finite element analysis has been adopted for numerical solution along with code validation and grid
independency test to ensure the numerical accuracy. It has been found that strengthening of magnetic field tries to
reduce the heat transfer rate, whereas increment of heater distance augments the heat transfer rate. Results analysed
on the basis of Nusselt number and average fluid temperatures are shown by related contours, plots and graphical
analysis. Therefore, higher heat transfer rate has been achieved for = 0.4.
Keywords: MHD convection; Bottom heater; Rayleigh Number; Hartmann Number; Magnetic Field.
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2.05
The Enhancement of Heat Transfer in a Circular Tube with
Insert and without Insert by using the Finite Element Method
Sabbir Hossaina, Ujjwal Kumar Debb, Kazi Afzalur Rahmana aMechanical Engneering Department, Chittagong University of Engineering and Technology
bDepartment of Mathematics, Chittagong University of Engineering and Technology
Abstract
This paper presents a Finite Element based model of the heat transfer problem. The Enhancement of heat transfer with
mass in a tube has been investigated without insert and with insert i.e. combination of horizontally and vertically
arranged rectangular boxes of 5 mm thickness are being fitted perpendicular to the flow direction respectively at equal
distance from each other along the length. The combinations are composed of without insert, two inserts, four inserts,
six inserts, eight inserts and ten inserts. The purpose of using inserts is to scatter the fluid particles in the laminar flow
which increases the heat transfer. An 800 mm long pipe with 26 mm inner diameter and 5 mm thickness is considered
in our simulation. The simulations have been completed for both stationary and time dependent conditions with
Reynolds number 1600~2400. A constant heat flux is generated at the boundary layer of the tube close to the flowing
fluid around the boundary layer. We also have shown the comparisons of heat transfer rate among different combinations
of inserts to understand the heat transfer phenomenon for the computational domain.
Keywords: CFD Analysis, Mass transfer, FEM Analysis, Boundary heat flux, Boundary element
20.6
Effect of Corner Radius of a T- Junction M ini-Square Channel on
Fluid Flow and Heat Transfer in the Developing Region: A Three
Dimensional Numerical Simulation.
Abhik Majumdera, Sambit Majumderb
aNational Institute of Technology, Agartala, 799055, India
bNational Institute of Technology, Agartala, 799055, India
Abstract
In recent years, there is a trend of miniaturization of devices like heat exchangers, microfluidic devices, MEMS and
electronic chip devices. The study of fluid flow in these devices is of great significance nowadays. Due to small
dimensions, the entrance design is a matter of concern and importance. In this work, the effect of variation of corner
radius, on thermo- hydrodynamic characteristics of a three dimensional model of T-junction square mini-channel duct
of 2 mm sides is studied under constant heat flux applied (H2 type) on the horizontal part. The length of horizontal
section is 300 mm. The T junction is placed at the middle of 60 mm long vertical section. The numerical simulation
was done in general purpose CFD package FLUENT. The simulation is performed for two Reynolds number, one in
laminar flow range (Re 1000) and the other in turbulent flow range (Re 3200). It is observed that incorporation of fillets
at T-junction changed the nature of the fluid flow and heat transfer locally. Variations in velocity and Nusselt number
have been observed in both the laminar and turbulent flow regime. Within developing region local velocity is found to
be increasing with increase in corner radii towards downstream of the channel in laminar and turbulent flow. Whereas
the local Nusselt numbers are less as compared to base model for all heating conditions and corner radii, resulting in
local wall temperature rise. Hence, such incorporation of corner radii may accelerate the uniform flow velocity growth.
Vortices are observed to be diminishing near the junction with increase in corner radii.
Keywords:T junction; corner radius; heat transfer; fluid flow; local Nusselt number.
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2.07
Natural convection of fluid with viscous dissipation and variable
viscosity from a heated vertical wavy surface
Nazma Parveen and Md. Abdul Alim Department of Mathematics, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh
Abstract
A numerical analysis used to simulate the effects of the viscous dissipation and variable viscosity on natural convection
heat transfer boundary layer flow along a vertical wavy surface has been investigated. A simple coordinate
transformation is employed to transform the wavy surface into a flat plate. The boundary layer equations and the
boundary conditions are discretized and solved numerically using by the finite difference scheme known as the Keller-
box method. Effects of the viscous dissipation and variable viscosity parameter on the skin friction coefficients, the local
Nusselt number, the streamlines as well as the isotherms are presented and discussed in detail. The results of this
investigation illustrate that the skin friction coefficient increases with an increase of the variable viscosity and viscous
dissipation parameter, while the local Nusselt number at the heated surface decreases with increasing variable viscosity
and viscous dissipation parameter.
Keywords: Viscous dissipation; variable viscosity; natural convection; uniform surface temperature; Keller-box method;
wavy surface
2.08
Effect of magnetic field on natural convection in a C -shaped
cavity filled with ferrofluid
Satyajit Mojumder, Sourav Saha, Sumon Saha, M.A.H. Mamun Department of Mechanical Engineering , Bangladesh University of Engineering and Technology,Dhaka-1000.
Abstract
In this paper, natural convection heat transfer has been analyzed for a C-shaped cavity filled with ferrofluid. Cobalt-
kerosene ferrofluid is selected here for different solid volume fractions ( = 0 ~ 0.15). Galerkin weighted residual method is applied to obtain the numerical solution. Simulations are carried out for a wide range of Rayleigh (Ra = 103 ~ 107)
and Hartmann (Ha = 0 ~ 100) numbers for both the ferrofluid and the plain fluid. From this work, it is found that
higher Rayleigh number enhances the heat transfer rate significantly, whereas presence of magnetic field tries to retard
convection. Moreover, addition of 15% solid volume fraction of nanoparticle can augment the heat transfer rate up to
52.65% at moderate Rayleigh number compared to the base fluid. By an optimization of these parameters, effective
heat transfer control equipment can be developed. Results are interpreted on the basis of streamline and isotherm
patterns, and average Nusselt number of the heated wall and average fluid temperature of the cavity.
Keywords: Ferrofluid; C-shaped cavity; Magnetic field; Natural convection.
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2.09
Soret and Dufour effects in an M HD flow over a porous rotating
disk using HAM
Navid Freidoonimehra, Mohammad Mehdi Rashidib,c, Mohammad Shakhaoath
Khand, Mohammad Ferdowse aYoung Researchers & Elite Club, Hamedan Branch, Islamic Azad University, Hamedan, Iran
bMechanical Engineering Department, Engineering Faculty of Bu-Ali Sina University, Hamedan, Iran
cMechanical Engineering Department, University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University,
Shanghai, Peoples Republic of China
dDepartment of Chemical Engineering, University of Newcastle, NSW 2308, AUSTRALIA
eDepartment of Mathematics, University of Dhaka, Dhaka-1000, Bangladesh
Abstract
The main concern of the present article is to study the steady MHD flow past a porous rotating disk using a semi
numerical/analytical method named Homotopy analysis method (HAM). The von-Karman transformations are
employed to transform the governing equations into system of nonlinear ordinary differential equations (ODEs). The
results of the present study are compared with numerical quadrature solutions employing a shooting technique with
excellent correlation in an especial case. The effects of flow physical parameters such as magnetic interaction parameter,
suction parameter, Prandtl number, Schmidt number, Soret and Dufour number on the fluid velocity, temperature and
concentration distributions are presented graphically and discussed in details. Results show that the effect of increasing
Soret number or decreasing Dufour number tends to decrease the temperature distribution while enhances the
concentration distribution.
Keywords: Heat and mass transfer; MHD flow; Rotating disk; HAM; Soret effect; Dufour effect
2.10
Effect of fin and insert on the performance characteristics of
Open Loop Pulsating Heat Pipe (OLPHP)
M Lutfor Rahmana , Fariha Mira*, Sumaiya Nawrina, R A Sultana, and
Mohammad Alib aDepartment of Mechanical Engineering, MIST, Mirpur, Dhaka, Bangladesh
bDepartment of Mechanical Engg., BUET, Dhaka, Bangladesh
Abstract
The pulsating heat pipe, a serpentine tube of capillary dimension with many turns, has great impact on todays successful thermal management. It is an ascending technology to satisfy present requirement of increasing thermal
performance. Focusing on this, an experiment has been done on the open loop pulsating heat pipes (OLPHP) to observe
their performance characteristics by using two types of working fluid by varying inclination angles. The experiment is
performed on 2.5 mm inner diameter and 3 mm outer diameter OLPHP with an insert of copper wire of 1 mm diameter
and fins are added on the condensation section. This investigation is done using methanol and ethanol with 50% filling
ratio in OLPHP with 8 loops. In this experiment the effects on the performance of using fins with insert with two
different fluids (methanol and ethanol) and the variation of inclination angles are investigated. The results show that
the performance characteristics in all the circumstances are better for setup with fin and insert than the normal setup.
As higher thermal resistance indicates better performance, so we can say that setup with methanol performs better than
ethanol. This performance is best at 45 inclination angle. It can be seen that, higher the inclination angle, better the
performance and this performance is best at 45 inclination angle for this experiment.
Keywords: Open loop closed end pulsating heat pipe; evaporation; condensation; inclination angle; thermal conductance.
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2.11
Experimental investigation on heat transfer characteristics of an
Open Loop Pulsating Heat Pipe(OLPHP) with fin
Md Lutfor Rahmana, Pijush Kanti Sahaa,*, Fariha Mira, Asfia Tanjim Totinia,
Sumaiya Nawrina and Mohammad Alib aDepartment of Mechanical Engineering, MIST, Mirpur, Dhaka, Bangladesh
bDepartment of Mechanical Engineering, BUET, Dhaka, Bangladesh
Abstract
This paper presents an experimental investigation of an open loop pulsating heat pipe of 2 mm inner diameter and 2.5
mm outer di0061meter with fin in condenser section to study the heat transfer performance. The setup is an open loop
closed end pulsating heat pipe creating a total of 8 loops with total length of 25 cm. The performance characterization
will be done for methanol as working fluid with 50% filling ratio. The evaporator section is 5 cm in length and the
condensation section is of 8 cm with an adiabatic section of 12 cm. The evaporator section is heated by electrical input
using Ni-Chrome wire and the condenser section is cooled by fan. The effects of fin in PHP for open loop will be analyzed
for heat transfer characteristics and the results are compared with that of without fin keeping constant the other
parameters. The results explore the possibility of using the open loop pulsating heat pipe as an integrated structure to
achieve higher thermal conductance to the host substrate. Effect of gravity, pressure differential in the system,
temperature, heat input etc. may have influence in this fact due to which 45 inclined position of finned structure shows the best performance.
Keywords: Open loop closed end pulsating heat pipe; evaporation; condensation; inclination angle; thermal conductance.
2.12
Study of Thermal Conductivity and M echanical Property of
Insulating Firebrick Produced by Local Clay and Petroleum Coal
Dust As Raw M aterials
Md. Hamidur Rahmana,*, Md.Tariqul Islama, Tamzid Ibn Minhaja, M.A.K.
Azada, Md.Mehedi Hasana and A.A.Md. Rezaul Haquea
aDepartment of Materials and Metallurgical Engineering
Bangladesh University of Engineering and Technology (BUET), Dhaka, Bangladesh
Abstract
Thermal insulation is one of the major requirements for various industrial applications. In this study the evaluation of
thermal conductivity and mechanical property of an insulating refractory was carried out at elevated temperature. As
additive, coal dust and 4-5wt% water were mixed with local clay. After forming the bricks by conventional uniaxial
pressing method, the samples were first air dried for 2 hours at ambient temperature of 30C, then oven dried for 8-10
hours at 110C and finally fired in furnace for 6 hours at 1050C. The combustion of fully combustible coal incorporated
extra porosity in the final products resulting in enhanced thermal insulation. As experimental variables, three different
sets of coal particle size range (coarse: 100-500 m, medium 20-100 m, fine: less than 20m) and four different coal
percentages were used. The results thus obtained showed that increased fineness of coal dust for a fixed coal percentage
improved crushing strength and porosity and decreased thermal conductivity. In contrast, for a fixed coal particle size
range, crushing strength and thermal conductivity decrease and the percentage of porosity increases with the increase
of coal percentage.
Keywords: Thermal Insulation; Fireclay; Coal dust; Insulating Refractory; Porosity; Thermal Conductivity.
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2.13
Effect of fin and insert on the performance characteristics of close
loop pulsating heat pipe (CLPHP)
M Lutfor Rahman1, Sumaiya Nawrin1,, Rasel A Sultan1, Fariha Mir1,
Mohammad Ali2
1Military Institute of Science and Technology, Mirpur Cantonment, Dhaka-1216, Bangladesh
2Bangladesh University of Engineering & Technology, Dhaka-1000, Bangladesh
Abstract
The pulsating heat pipe, a serpentine tube of capillary dimension with many turns, has great impact on todays successful thermal management. It is an ascending technology to satisfy present requirement of increasing thermal
performance. Focusing on this, an experiment has been done on the close loop pulsating heat pipes (CLPHP) to observe
their performance characteristics by using two working fluids with varying inclination angles of 0 (vertical), 30 and
45. The experiment is performed on 2.5 mm inner diameter and 3 mm outer diameter CLPHP with an insert of copper
wire of 1 mm diameter and fins are added on the condensation section where the evaporation section is 50 mm, adiabatic
section is 120 mm and condensation section is 80 mm.This investigation is done using ethanol and methanol with 50%
filling ratio in CLPHP with 8 loops. Methanol shows better performance at 45inclination than ethanol due to their
physiochemical properties at different conditions.In this experiment the effects on the performance of using fins with
insert and the variation of inclination angles are investigated. The results show the better performance characteristics
and enhancement of heat transfer in the present experimental set-up because of using fin and insert.
Keywords: Pulsating heat pipe; Thermal performance; Close loop pulsating heat pipe (CLPHP); Insert of Copper wire;
fin on condensation section
2.14
An experimental investigation on the effect of fin in the
performance of closed loop pulsating heat pipe (CLPHP)
M Lutfor Rahman1, Rasel A Sultan1,, T Islam1, Noor M Hasan1, Mohammad Ali2
1Military Institute of Science and Technology, Mirpur Cantonment, Dhaka-1216, Bangladesh
2Bangladesh University of Engineering & Technology, Dhaka-1000, Bangladesh
Abstract
Pulsating heat pipes (PHP) have created a newer arena and promising possibilities as passive devices for heat transfer
applications, especially suited for thermal management of electronics. A closed loop pulsating heat pipe (CLPHP) made
of copper with 2 mm ID and 2.5 mm OD with fin in the condenser section is used in the present work to evaluate the
heat transfer performances where the evaporation section is 50 mm, adiabatic section is 120 mm and condensation
section is 80 mm. The attempt is to analyze and compare the effects on the heat transfer performances of CLPHP with
finned and un-finned condenser section with inclination angle of 0 (vertical), 30 and 45. Methanol is used as working
fluid with 50% filling ratio in CLPHP with 8 loops during the experimentation. The experimental results indicate a
strong influence of gravity and thermo physical properties of the working fluid on the performance of the CLPHP
studied with different orientation and heat load. The results demonstrate the effect of fin used in condenser section, the
input heat flux, inclination angle orientation and physiochemical properties of the working fluid on the thermal
performance of the device. The finned CLPHP at 45 inclination exhibits the considerable enhancement of heat transfer
compared with that of CLPHP without fin.
Keywords: Electronic Cooling; Pulsating heat pipe (PHP); Close loop pulsating heat pipe (CLPHP); Thermal
performance
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2.15
Effect of Waste Heat Recovery on Drying Characteristics of
Sliced Ginger in a Natural Convection Dryer
Jnyana R. Patia , Santosh K. Hottaa, , P. Mahantab a Centre for Energy, Indian Institute of Technology, Guwahati- 781039
b Department of Mechanical Engineering, Indian Institute of Technology, Guwahati- 781039
Abstract
In the present work, quality drying characteristics of sliced ginger were studied utilizing the concept of waste heat
recovery in a biomass operated natural convection dryer with sensible heat storage material (SHSM) and phase change
material (PCM). Ginger slices (2 and 4 mm thickness) were dried from initial moisture content (MC) 88-90 % (w.b.) to
final moisture content 11-12% (w.b.) with hot air maintained at temperature 600C, air velocity 0.2 m/sec, atmospheric
average relative humidity 74% and ambient temperature 250C It was observed that the biomass consumption and
melting time of PCM were significantly reduced due to the use of waste heat. The optimum drying time was found to
be 5.5 h for 2 mm thick ginger slices. Color, texture and aroma were found better in treated sample.
Keywords: Waste heat recovery; Natural convection dryer; Phase change material; Quality drying
2.16
Ground source heat pump system controlled by refrigerant
average density
Koutaro Tsubakia*, Yuichi Mitsutakea aSaga University, Honjo 1, Saga, 840-8502, Japan.
Abstract
A ground source heat exists in a ground shallower than about 100 m in depth. The ground source heat was applied for
heat pump for air conditioning and snow melting, etc. However it is not popular in South area of Japan. We focus on
the ground source heat application in warm region, especially for air cooling. The ground temperature at isothermal
layer, about under 5m depth, is constant at about 18 C in Saga, Japan. This temperature is lower than the temperature
required for air cooling. Then a heat pipe with ground source heat can be used instead of a heat pump with atmosphere
heat source, usually used for air cooling. Heat pipe could operate with smaller energy consumption than heat pump.
Nevertheless the cycle operated like heat pipe is not used for ground heat source application. The novel ground source
heat application cycle, which could operate as heat pump and heat pipe, suit for an air cooling was investigated in this
research. The cycle operation condition is controlled by the average density. The cycle simulation of this cycle is
investigated. From the calculation results, heat transfer rate and exergy loss of cycle changed with refrigerant average
density. And also the best density condition was changed with the heat source temperature. Heat pipe operation could
operate as 1.32 times (R410A) and 1.34 times (R407C) higher the heat transfer rate per unit the total irreversible loss
compared with heat pump operation (P = 0.1 MPa). And heat pump operation (P = 0.1 MPa) could increase a heat
transfer rate 1.23 times (R410A) and 1.29 times (R407C) compared with heat pipe operation.
Keywords: Ground source heat; Heat pump; Heat pipe; Air conditioning
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2.17
Thermal Diffusion Effect on Unsteady Viscous M HD M icropolar
Fluid Flow through an Infinite Vertical Plate with Hall and Ion -
slip Current
Nisat Nowroz Anikaa, Md. Mainul Hoqueb, Sheikh Imamul Hossainc
and Md. Mahmud Alamc
aDepartment of Mechanical Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
b*Department of Chemical Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
cMathematics Discipline, Khulna University, Khulna-9208, Bangladesh
Abstract
An analysis is carried out to study the effect of Hall and Ion-slip current and heat transfer characteristics over an
infinite vertical plate for micropolar fluid in the presence of magnetic field. The governing boundary layer equation first
transformed into non-dimensional form and resulting non-linear system of partial differential equations are then solved
numerically by using the robust implicit finite difference technique. Also the unconditional stability and convergence
test has been carried out to establish the effect of shear stresses, couple stress, Nusselt number and Sherwood number
on the flow field. Finally, the effects of various parameters are separately discussed and shown graphically.
Keywords: Micropolar fluid; Hall current; Ion-slip current ; Thermal diffusion.
2.18
Effects of geometric parameters on the flow characteristics for
turbulent flow in a wavy finned-tube heat exchanger: CFD
modeling
Arafat A. Bhuiyan1,3, , M.Ruhul Amin2 and A K M Sadrul Islam3 1Faculty of Science, Engineering and Technology, Swinburne University of Technology, VIC-3122, Australia.
2Department of Mechanical Engineering, Montana State University, Bozeman, Montana,MT 59717-3800, USA
3Department of Mechanical Engineering, Islamic University of Technology (IUT), Gazipur-1704, Bangladesh.nt
Abstract
In this study, the effects of thermal and hydraulic characteristics of wavy fin and tube heat exchanger are investigated.
Simulation has been carried out by a commercial computational fluid dynamics code, ANSYS CFX12.0. The main
objective of this study is to investigate the flow characteristics in turbulent flow. Results are predicted for the turbulent
flow regime (2100Re7000) and compared with authors previous work for laminar (400Re1200) and transitional (1300Re2000) flow regime. Regarding turbulence, the k- model was used to predict the turbulent flow characteristics with 5% turbulence intensity. Predicted results were compared with the experimental data for the purpose of validation
and the discrepancy is found within 10% in error range. Parametric study was conducted for different pitches and wavy
angles. Flow characteristics obtained for the turbulent range is in line with the pattern observed in laminar and
transitional ranges. This study demonstrates a clear understanding and relationship of among different flow ranges and
the effects of different geometric parameters on the performance of heat exchanger.
Keywords: Wavy fin tube heat exchanger, CFD modelling, Friction factor, Colburn factor, Efficiency index, Reynolds
number.
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2.19
Experimental investigation of transient heat transfer on a solid
surface, with fire retardant fabric under hot air impinging jet
A.K.M. Nazrul Islama, , Md. Ashraful Islama, Manabendra Sahab aDepartment of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh
bCentre for Energy Technology, School of Mechanical Engineering, The University of Adelaide, SA 5005, Australia
Abstract
This paper represents an experimental investigation of the transient heat transfer on a solid base plate (mimic to skin)
covered by fire retardant fabric (Kevlar 49), under hot air jet impingement. The study was carried out by a fabricated
attachment with an axial flow wind tunnel for horizontal hot air jet impingement. The hot air jet was impinged on a
vertical base plate at different velocities and temperatures. A set of experimental conditions was considered to
understand the various heat transfer phenomenon. The hot air jet temperatures were 115 and 125 oC respectively and
jet velocities were 12, 15, and 19 ms-1 respectively at the exit point of the nozzle. The surface temperatures of the solid
base plate are used to calculate the heat flux, local heat transfer coefficient, and Nusselt numbers. The maximum heat
transfer is found on base plate, whilst the maximum decrease of heat flux is observed on fire retardant fabric. This
experimental model can enhance the understanding and insights of the heat transfer process through permeable fabric.
Keywords: Heat transfer; jet impingement; fire retarding fabric; Nusselt number.
2.20
Natural Convection Flow and Heat Transfer in an Enclosure
Containing Staggered Arrangement of Blockages
Draco Iyia and Reaz Hasanb
aDepartment of Mechanical Engineering, School of Engineering Robert Gordon University, Aberdeen, AB10 7GJ, United Kingdom
bDepartment of Mechanical and Construction Engineering, Northumbria University at Newcastle upon Tyne, NE1 8ST, United Kingdom
Abstract
The work reported in this paper is a numerical study of airflow and heat transfer for low turbulence buoyancy-driven
flow in a rectangular cavity partially filled with solid objects. The two vertical walls were maintained at constant
temperatures giving a temperature differential of 42.2 C resulting in a characteristic Rayleigh number of 1.45109. Two
different types of blockage arrangements were considered for analysis, and these consist of In-line and Staggered
arrangements of 126 and 123 objects. In all cases, steady state flow and wall heat transfer data at the mid-height
and mid-width of the cavity are presented. The flow domain displayed a stable core region and the average core
temperature was found to be strongly influenced by different stacking arrangement of solid objects. In general, the
staggered arrangement resulted in lower heat transfer through the surfaces which is linked with the suppression of
turbulence within the boundary layers close to the surfaces.
Keywords: Low turbulenc, Natural convection, Heat transfer, CFD, Product stacking and arrangement
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2.21
Thermal and hydraulic performance analysis of rectangular fin
arrays with perforation size and number
Mehedi Ehteshum, Mohammad Ali, Md. Quamrul Islam, Muhsia Tabassum Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh
Abstract
Enhancement of heat removal and reduction of fin size become a major concern in designing heat exchanger equipment.
The present paper reports an experimental analysis to investigate the turbulent heat transfer performance of rectangular
fin arrays, both solid and circular perforations along the length of the fins. The size and number of circular perforation
have been varied. Tests have been conducted in a horizontal wind tunnel equipped with forced draft fan. The data are
obtained by varying flow velocities while maintaining constant heat input and taken over a period of time. The Reynolds
number is varied between 6104 through 25104. The heat loss due to radiation and convection is taken into account
during calculation. Thermal performances and effectiveness of perforation and equivalent surface solid fin arrays have
been evaluated and compared. Results show remarkable heat transfer enhancement, lower thermal resistances, pressure
drop and higher efficiencies, effectiveness for perforated fins with increasing number of perforations in addition to the
considerable reduction in weight in comparison with solid fin arrays.
Keywords: Perforated fins; Turbulent flow; Fin effectiveness; Heat transfer; Heat transfer enhancement; Perforation
size; Perforation number;
2.22
Analysis of Heat Transfer in Channel Flow Subject to Sine -Bump
Heating
Umera Sarjanaa, M. Zakir Hossainb, AKM Monjur Morsheda aDepartment of Mechanical Engineering, Bangladesh University of Engineering and Technology (BUET), Dhaka.
bDepartment of Mechanical and Materials Engineering, University of Western Ontario, Ontario, Canada.
[email protected] [email protected] [email protected]
Abstract
Convection in a channel subject to a distributed sinusoidal bump like heating applied at the lower wall has been studied.
It is found that small wave number heating provides large plumes whereas large wave number heating provides a
uniform temperature distribution at the upper part of the channel. Heat transfer is more efficient at low Reynolds
number with small wave number heating.
Keywords: Convection; Heating; Reynolds number; sinusoidal bump;
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2.23
Effect of a DC Field on Temperature Distribution in a Thin FGM
M etal Line Subjected to Distributed Local Heating Sources
Abhishek Kumar Ghosh, Md. Rejaul Haque and S. Reaz Ahmed Bangladesh University of Engineering and Technology, Dhaka- 1000, Bangladesh
Abstract
The effect of a direct-current field on the temperature distribution in a thin, non-uniform functionally graded metal line
subjected to distributed local heat sources is investigated. The material properties of the metal line are assumed to vary
over the span following a linear functional relationship. Bump-like heat sources of different profiles are considered to
simulate the condition of distributed local heating of the metal line. The governing differential equations associated
with the electrical and thermal problems are derived in terms of variable thermal and electrical conductivity of the
material. The solution of the coupled boundary-value problem is then obtained using a finite-difference computational
scheme. The temperature distributions in the FGM line are determined for different environmental conditions as a
function of intensity of the DC field.
Keywords: Functionally-graded metal line; distributed heat source; temperature distribution; direct-current field.
2.24
Dean-Taylor Flow with Convective Heat Transfer through a
Coiled Duct with Strong Curvature
Rabindra Nath Mondala , Raju Royb and Md. Zohurul Islamb a Department of Mathematics, Jagannath University, Dhaka-1100, Bangladesh
b Department of Mathematics and Statistics, jessore University of Science and Technology , Jessore-7408, Bangladesh.
Abstract
The present study addresses numerical prediction of Dean-Taylor flow through a coiled rectangular duct of curvature
0.5. Spectral method is used as a basic tool to solve the system of non-linear partial differential equation. The emerging
parameters controlling the flow characteristics are the rotation parameter i.e. , (incorporating Coriolis force), Grashof
number , Prandtl number , aspect ratio , and pressure-driven parameter i.e. Dean number Dn (incorporating
centrifugal force). The flow structures are examined for the effects of rotation parameter and pressure-driven parameter.
We investigated unsteady flow characteristics for two cases of the duct rotation, Case I: Positive rotation and Case II:
Negative rotation. For positive rotation, we investigate the unsteady flow for the Dean numbers Dn = 1000 and 2000
over the Taylor number , and it is found that the chaotic flow turns into steady-state flow through periodic or multi-
periodic flows, if Tr is increased in the positive direction. For negative rotation, however, unsteady flow characteristics
are investigated over the Taylor number , and it is found that the unsteady flow undergoes through various flow
instabilities, if Tr is increased in the negative direction. Contours of secondary flow patterns and temperature profiles
are obtained at several values of Tr, and it is found that the unsteady flow consists of two-, three-, four-, five-, six-,
seven- and eight-vortex solutions. Convective heat transfer is also investigated, and it is found that the chaotic flow
enhances heat transfer more significantly than the steady-state or periodic solutions.
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2.25
M HD free convection fluid flow through parallel plates with hall
current in a rotating system
Rina Perven, Md. Mahmud Alam
Mathematics Discuipline,Science, Engineering and Technology School, Khulna University, Khulna-9208, Bangladesh
Abstract
An attempt has been made to study the influence of inclined magnetic field with hall current of a viscous incompressible
electrically conducting free convection fluid flow through the parallel plates in a rotating system. The channel is rotating
with uniform angular velocity about an axis normal to the plates. For numerical solution, the problems have been
transferred into dimensionless form and then the explicit finite difference technique has been used. The stability
conditions and convergence criteria of the explicit finite difference scheme are established for finding the restriction of
the values of various parameters to get more accuracy. The effects of Rotation parameter R , Hall parameter m ,
Magnetic parameter 2( )M and Angle of inclination on primary and secondary velocities have been shown in
graphical representations. Finally the effects of these parameters have been analyzed by the figures of local shear stress
and average current density at the moving plates of channel.
Keywords: Hartmann number; Rotating system; MHD free convection; Inclined magnetic field; Finite difference
technique
2.26
Effects of viscous dissipation on natural convection flow over a
sphere with temperature dependent thermal conductivity in
presence of heat generation
Md. Raihanul Haquea, Md. M. Alama, Mohammad Mokaddes Alib, Rehayet Karimc, a Department of Mathematics, Dhaka University of Engineering and Technology, Gazipur-1700,Bangladesh
b Department of Mathematics, Mawlana Bhashani Science and Tech. University, Tangail-1902, Bangladesh
c Department of Mathematics, Chittagong University of Engineering and Technology, Chittagong-4349, Bangladesh
Abstract
In this paper, the steady two-dimensional laminar incompressible flow over a sphere in the presence of viscous dissipation
and heat generation is considered. Thermal conductivity is assumed as a linear function of temperature. The governing
equations are solved numerically by numerical solution strategy as per requirement and suitability. The obtained self
similar equations are then solved numerically by an implicit, tri-diagonal, finite-difference method with Keller Box
scheme. Favorable comparison with previously published work is performed. Computations are performed for a wide
range of the governing flow parameters such as thermal conductivity variation parameter , heat generation parameter
Q, Prandtl number Pr and Eckert number Ec. The computational findings for the dimensionless velocity, temperature
profiles as well as for the skin-friction coefficient and heat transfer rate are presented in tabular form and graphically.
Keywords: Variable thermal conductivity; Heat generation; Eckert number
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3.01
Transient Analysis of 3-Lobe Bearings Considering Surface
Roughness Effect For A Gas Turbine
Nabarun Biswasa,Prasun Chakrabortib
a*Department of NIT Agartala,Jirania,Tripura-799046,India
bDepartment of NIT Agartala,Jirania,Tripura-799046,India
Abstract
The performance of a 3-lobe bearing is investigated by means of three-dimensional computational fluid dynamics
analysis. Surface roughness effects were included in the computation of unsteady transient analysis of 3-lobe bearing,
taking into account gravity. Each of the lobes is placed at a distance of 120 degree. In this paper K-Epsilon turbulence
model is used. The 3-lobe bearing is designed in Gambit software, the journal is modeled as a moving wall with an absolute rotational speed of 6000 rpm. Design parameters like L/D ratio, total pressure distribution, surface roughness
and lubricant flow properties like turbulent viscosity and velocity magnitude are considered for the analysis The flow
is simulated using Ansys Fluent software.
Keywords: 3-lobe; viscosity; pressure; wall shear stress; surface roughness.
3.02
Experimental investigation on the performance of NACA 4412
aerofoil with curved leading edge planform
M. Nazmul Haquea*, Mohammad Alia , Ismat Araa
aDepartment of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.
Abstract
Aircraft wings are the lifting surfaces with the chosen aerofoil sections. The efficiency as well as the performance of an
aircraft mostly depends on the aerodynamic characteristics e.g. lift, drag, lift to drag ratio, etc of wings. Besides many
factors, the effects of wing shape are also crucial to aircraft performance. This paper represents the experimental
investigation to explore better aerodynamic performance by incorporating curvature at the leading edge of a wing. A
wooden model with straight leading and trailing edge i.e. rectangular planform and another model with curved leading
edge and straight trailing edge are prepared with NACA 4412 aerofoil in equal length (span) and surface area. Both the
models are tested in a closed circuit wind tunnel at air speed of 85.35 kph (0.07 Mach) i.e. at Reynolds number 1.82 x
105. The static pressure at different angles of attack (-4, 0, 4, 8, 12, 16, 20 & 24) are measured from both
upper and lower surfaces of the wing models through different pressure tapings by using a multi-tube water manometer.
From the static pressure distribution, lift coefficient, drag coefficient and lift to drag ratio of both the models are
analyzed. After analyzing the data, it is found that the curved leading edge wing planform is having higher lift coefficient
and lower drag coefficient than the rectangular wing planform. Thus, the curved leading edge planform is having higher
lift to drag ratio than the rectangular planform.
Keywords: Aerofoil; aerodynamic performance ; coefficient of lift; coefficient of drag; lift to drag ratio; Reynolds number.
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3.03
Experimental Study of Unsteady Flow in a Shock Tube for
Needle-Free Drug Delivery
Guang Zhang1, Yun Sung Kim2, Gyu Wan Kim3, Toshiaki Setoguchi4 and Heuy
Dong Kim1,2,3* 1. 2. 3. Department of Mechanical Engineering, Andong National University, Andong 760-749, Korea
[email protected], [email protected]*
4. Department of Mechanical Engineering, Saga University, Saga, Japan
Abstract
Recently, the needle-free delivery system has been widely used in medical fields due to its convenience in delivering
drug particles into human body without any external needles. In order to penetrate through the outer layer of the skin,
drug particles need to obtain enough momentum, which is achieved by accelerating drug particles in a Contoured Shock
Tube (CST). The CST consists of a micro shock tube with two diaphragms and an expanded supersonic nozzle. In the
present study, experimental studies were carried out by pressure measurement. Six high sensitive pressure transducers
were used for recording pressure changes as the shock wave moved through different locations along walls in the test
section. From which, data on shock wave propagation could be obtained. Different diaphragm pressure ratios were
conducted to demonstrate effects of initial diaphragm pressure ratios on shock wave propagation. Shilieren visualization
was also performed to observe shock wave propagation and shock wave structure in the present experimental shock
tube model. The characteristic of the internal flow and shock wave system have been studied and analyzed in details
in the present shock tube model.
Keywords: Shock tube, Supersonic nozzle, Needle-free drug delivery, Shock wave propagation, Unsteady flow.
3.04
An Empirical M odel for Annular Flow in Gas Wells
Aziz Rahman Assistant Professor, Department of Process Engineering, St Johns, NL, Canada
E-mail: [email protected]
Abstract
In annular flow of a natural gas well, liquid may be present in entrained droplets as well as in the film near to the well
wall. A number of models have been proposed over the past 50 years to predict film thickness in pipes with vertical
two-phase annular flow. Earlier models are based on correlations from the limited range of experimental data. The
proposed modified film thickness model developed from a range of experimental data. The experimental data covers
conditions of superficial liquid velocities ranging from 0.610-3 to 0.39 m/s; superficial gas velocities ranging from 13.4
to 110.6 m/s; and diameters ranging from 12 to 51 mm. The proposed model is compared with the available experimental
data in the literature. Model predictions are in good agreement with the available experimental data set. The modified
film thickness model helps to explain the fundamentals of annular flow, which in turn is beneficial to the natural gas
production industry as it further develops the understanding of production mechanics.
Keywords: annular flow; two phase flow; flim thickness; pressure gradeint; entranment; gas well;
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3.05
W inglet Type Dielectric Barrier Discharge Plasma Actuators:
Performance Characterization and Numerical Comparison
A.N.M. Mominul Islam Mukuta, Hiroshi Mizunumab, Obara Hiromichib and
Takehiko Segawac aDhaka University of Engineering & Technology (DUET), Gazipur-1700, Bangladesh
bTokyo Metropolitan University, Tokyo 192-0397, Japan cNational Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
Abstract
Winglet type dielectric barrier discharge plasma actuator (PA) with two exposed electrodes have been investigated
experimentally in a quiescent air and numerically modeled. Three arrangement of electrode positions are used: leading
edge type (here after L PA), middle edge type (here after M PA), and trailing edge type (here after T PA) to investigate
the effect of electrode position on induced flow. When the electrodes are located at the leading edge of the winglet PA,
the stream wise flow is effectively enhanced on the covered electrode; on the other hand when the electrodes are located
at the trailing edge, the friction loss is minimized for the near-wall high shear flow over the winglet and thus the highest
momentum integral is obtained for the downstream jet-like flow. As all three type of PAs have two exposed electrodes,
hence two separate jet flows are induced which are unified to a single jet after the winglet trailing edge. The electrode
location also influences the unification velocity at downstream. The longer distance between trailing edge and embedded
electrode reduces the downstream unified velocity. Particle image velocimetry (PIV) technique has been implemented
to investigate the flow field. Simulation results are found to be consistent and in good agreement with experimental
data.
Keywords: dielectric barrier discharge plasma actuator; velocity profile; flow control; PIV; jet; CFD
3.06
U ltra Compact Heat Exchanger W ith Geometry Induced Wall
Jet
A K M M. Morshed Morshed (Bangladesh), Fazlul Bari (Bangladesh), Aashique
Alam Rezwan Rezwan (Bangladesh)
Abstract:
Heat Exchanger (HX) is common but crucial equipment found in almost every engineering application which comes in
different types, sizes and shapes. Performance of the HX is directly related with the overall system performance.
Compactness of the HX is a good indication of its performance, usually the higher the compactness the higher the
effectiveness. Increasing compactness of the HX by reducing the channel dimension is fairly a simple but highly effective
technique. Although heat exchanger comprising of very small channel can achieve very high heat flux, its pumping
requirement for circulating liquid increases very sharply. The pumping requirement can be reduced by increasing the
number of channels either by vertical or horizontal stacking; the flow velocity through each channel is reduced for the
same total mass flow rate of the liquid. In this study a novel technique called geometry induced wall jet is proposed to
further enhance the performance of this heat exchanger comprising of small channels. The cross-flow from the wall jet
disrupts the boundary layer of the channel flow enhancing the heat removal capacity of the heat exchanger. A CFD
model has been developed using commercially available software package FLUENT to evaluate the overall thermal
performance of this new design heat exchanger. A parametric study of the flow rates and the effect of the jet locations
have been performed. Significant reduction in thermal resistance has been observed for proposed design.
Keywords: Heat Exchanger, Wall Jet, Heat Transfer Enhancemen
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3.07
Numerical Study of Sub-Nozzle Flows for the Weft Transmission
in an Air Jet Loom
Jin Hyeon Kim1, Toshiaki Setoguchi2 and Heuy Dong Kim1* 1. Department of Mechanical Engineering, Andong National University, Andong 760-749, Korea
[email protected], [email protected]*
2. Department of Mechanical Engineering, Saga University, Saga, Japan
Corresponding author: Prof. Kim, Heuy Dong ([email protected])
Abstract
The air jet loom is widely applied in the textile industry due to its high productivity, convenient controllability, high
filling insertion rate, low noise and low vibration levels. High-Speed air jet weaves the weft yarn, and transports it
through the weft passage. In the present study, a computational fluid dynamics method is applied to solve the
incompressible NavierStokes equations with one-equation Spalart-Allmaras turbulence model. Which is used to solve the flow filed in a weft passage. The aim of this analysis is to determine the distribution of the flow velocity along the
weft passage. Results revealed the strong relationship between air jet velocity and forces on the weft.
Key words: Air Jet Weft Insertion, Main Nozzle, Sub Nozzle, Air Jet Loom, Profile Reed
3.08
A study on multistage centrifugal pump performance
characteristics for variable speed drive system
Rakibuzzamana, Sang-Ho Suha , Kim Kyung-Wuka, Hyung-Ho Kima, Min Tae
Chob, In Sik Yoonb aDept.of mechanical Engineering, Soongsil University, Seoul, 156-743, South Korea
bDooch Co., 295 Sagok-ri, Jangan-Myeon, Hwaseong-si, Gyeonggi-do, 445-942, South Korea
Abstract
Nowadays centrifugal pumps are being widely used in the commercial, industrial and power plant applications and most
of pumps operated by constant speed drive system. Therefore, pump consumes a huge energy of each nations total energy. But it could be operated in variable speed drive system which would be provided energy saving. The purpose
of this study is to investigate the pump performance characteristics of the multistage centrifugal pump with the variable
drive system. For this study an experimental set up of the system was constructed to achieve the centrifugal pump
performances such as H-Q, -Q, P-Q curves and operating points which interact between performance and system curves. In the variable speed drive system, a vector controlled inverter driving (variable voltage variable frequency) was
installed in the experimental system. A numerical investigation also applied for getting the pump performances for the
validation and reliability of the pump design development and also the pressure and velocity effects in internal flows of
the pump are analyzed. For the numerical analysis, the Navier-Stokes equations were discretized by the finite volume
method and two equations transport turbulence (SST) model accounts for three dimensional steady flows. In the
experiment system, we also carried out system head performance of the three pumps in parallel to compare with one
pump system head for its validation. In order to get the energy saving rate using the inverter control variable speed
drive system instead of the constant speed drive system, it is necessary to identify the specific duty cycle of the pump
operation cycle and operating system curve of the pump. Hopefully, this paper will be useful as a guide for identifying
a method of implementing a variable speed drive system with inverter control in the variable flow and pressure system.
Keywords: Multistage centrifugal pump; Variable speed drive system; Inverter; Performance analysis; System curve;
SST turbulence model;
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4.01
Velocity and temperature distributions of laminar and transition
boundary layer flows along a heated vertical flat plate
Mohammad Zoynal Abedina,*, Mohammed Moinul Islama, Mashud Ranaa, Jinho
Leeb aDepartment of Mechanical Engineering, Dhaka University of Engineering & Technology, Gazipur-1700, Bangladesh
bSchool of Mechanical Engineering, Yonsei University, Seoul 120-749, Republic of Korea
Abstract
Time-developing direct numerical simulation (DNS) has been performed for the laminar and transition boundary layer
flows in the natural-convection and mixed-convection with aiding and opposing flows both in air and water along a
heated vertical flat plate. The results reveal that the velocity profile of water in the laminar natural-convection boundary
layer shows lower peak value compared to that in air and the temperature profile in water within the boundary layer
becomes ambient at a shorter distance perpendicular to the heated wall compared to that in air due to the effects of
higher Prandtl number of water. For laminar mixed-convection boundary layer, the velocity profile of water exhibits
lower values throughout the boundary layer compared to that in air. In the case of opposing flows both in air and water,
the velocity profiles show a sharp drop to a constant negative value in the outer boundary layer region. Furthermore,
for transitional natural-convection boundary layer in air, the magnitude of the velocity profile increases with an increase
in Grashof number due to the increasing trend in the boundary layer thickness. It is also found that the predicted heat
transfer rates in the natural-convection boundary layer both in air and water correspond quantitatively well with the
existing observations.
Keywords: Laminar flow; Transitional flow; Boundary layer, Freestream velocity, Prandtl number, Natural convection,
Mixed convection.
4.02
M odified NorrisReynolds OneEquation M odel M. M. Rahman1, A. K. M. Sadrul Islam2, M. J. Lampinen1 and T. Siikonen1
1Aalto University School of Engineering, P.O. Box 14400, FI00076 AALTO, Finland
2Department of Mechanical & Chemical Engineering,
Islamic University of Technology, Board Bazar, Gazipur 1704, Bangladesh
1E-mail: [email protected]
Abstract
A modified version of NorrisReynolds (NR) kequation turbulence model is proposed to account for the distinct effects
of lowReynolds number (LRN) and wall proximity. The turbulent kinetic energy k and the dissipation rate are evaluated using the ktransport equation in conjunction with the Bradshaw and other empirical relations. The eddyviscosity formulation maintains the positivity of normal Reynolds stresses and preserves the anisotropic characteristics
of turbulence in the sense that they are sensitized to rotational and nonequilibrium flows. The modified NR (MNR) model is validated against welldocumented flow cases yielding predictions in good agreement with the direct numerical simulation (DNS) and experimental data. Comparisons indicate that the MNR model offers some improvement over
the original NR model and competitiveness with the SpalartAllmaras oneequation model.
Keywords: Oneequation model, turbulence anisotropy, twolayer model, nonequilibrium flow.
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4.03
Unsteady M HD Casson Fluid Flow through a Parallel Plate with
Hall Current
Md. Afikuzzaman, M. Ferdows and Md. Mahmud Alam Mathematics Discipline, Khulna University, Khulna-9208, Bangladesh
**Mathematics Department, Dhaka University, Dhaka-1000, Bangladesh
Abstract
Unsteady MHD Casson fluid flow through a parallel plate with hall current is investigated. The uniform magnetic field
is applied perpendicular to the plates and the fluid motion is subjected to a uniform suction and injection. The lower
plate is stationary and the upper plate is moving. Explicit Finite Difference technique has been used to solve the
momentum and energy equations. The effect of pressure gradient, the Hall parameter and other parameters describing
in the equations are shown graphically. Effect of decaying parameter with different Casson number on primary velocity,
secondary velocity and temperature distributions are illustrated in the form of the graph.
Keywords: MHD; Heat Transfer; Hall Current; Finite Difference Techniques.
4.04
Unsteady M HD viscous incompressible Bingham fluid flow with
hall current
Afroja Parvin*, Tanni Alam Dola** and Md. Mahmud Alam ** *The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, I-34151 Trieste, Italy
**Department Civil Engineering, Bangladesh University of Engineering and Technology(BUET), Dhaka-1000, Bangladesh
***Mathematics Discipline, Science, Engineering and Technology School, Khulna University, Khulna-9208, Bangladesh
Abstract
An electrically conducting viscous incompressible Bingham fluid bounded by two parallel non-conducting plates has
been investigated in the presence of Hall current. The fluid motion is uniform at the upper plate and the uniform
magnetic field is applied perpendicular to the plate. The lower plate is fixed while upper plate moves with a constant
velocity. The governing equations have been non-dimensionalzed by using usual transformations. The obtained
governing non-linear coupled partial differential equations have been solved by using explicit finite difference technique.
The numerical solutions are obtained for momentum and energy equations. The influence of various interesting
parameters on the flow has been analyzed and discussed through graph in details. The values of Local Nusselt number,
Average Nusselt number, local Skin- Friction, Average Skin- Friction for different physical parameters are also
illustrated in the form of graph.
Keywords: MHD Flow; Hall parameter; Explicit finite difference technique; Stability analysis
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4.05
Physics of supersonic mixing in parallel and non -parallel streams
passing over base thickness
Mohammad Ali , TAGMZN Jubery, Sanchita Amin, M Quamrul Islam Department of Mechanical Engineering, Bangladesh University of Engg. and Technology, Dhaka 1000, Bangladesh
Abstract
The mixing flow field of two-parallel and non parallel gaseous streams has been studied numerically. The streams are
of air and hydrogen and come into contact after passing over a finite thickness base. The two gas streams are delivered
from a high-pressure reservoir and entering into the domain with atmospheric pressure. The two-dimensional unsteady
Navier-Stokes equations, energy, mass diffusion and species continuity equations are numerically simulated to analyze
the mixing layer in supersonic flow field. An explicit Harten-Yee Non-MUSCL Modified flux-type TVD (total variation
diminishing) scheme is used to solve the system of equations. An algebraic turbulence model is used to calculate the
eddy viscosity coefficient. Keeping constant the inlet pressure and velocity of the streams, the merging angle is varied
to observe the physics of flow fields, mixing of two-streams and mixing efficiency. The results show that the increase of
merging angle causes stronger interactions between two streams, high momentum exchange and eventually enhancement
of mixing between two streams.
Keywords: Supersonic combustor, mixing, shear layers, merging angle;
4.06
Numerical investigation of effect of M ach number over backward
facing step
Konica Sarker *a , Mohammad Ali b , Quamrul Islam b a Bangladesh Power Development Board, Dhaka, Bangladesh.
b Department of Mechanical Engineering, BUET, Dhaka-1000, Bangladesh
Abstract
A numerical study has been carried out to investigate the flow field characteristics of a transonic compressible flow over
a flat plate with backward facing step. The study has been performed by solving Two-Dimensional Navier-Stokes
equations. The system of governing equations has been solved, using an explicit Harten-Yee Non- MUSCL Modified
flux type TVD scheme and a zero-equation algebraic turbulence model to calculate the eddy viscosity coefficient. The
results presented in this paper are computed for fixed step height, h=7.5 mm and for different Mach numbers, M= 0.8,
1.0 1nd 1.2. The details on pressure, temperature and velocity field, together with recirculation length, expansion shock,
reattached shock, interaction of shock wave are reported. The variations of flow field characteristics due to change of
Mach number are also presented.
Keywords:Mach number; backward step;recirculation;
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5.01
Effects of Thermal Diffusion on Viscoelastic Fluid
Flow through a Vertical Flat Plate Sheikh Imamul Hossain and Md. Mahmud Alam1
Mathematics Discipline, Khulna University, Khulna-9208, Bangladesh
Abstract
Viscoelastic fluid flow through a semi-infinite vertical rigid plate with diffusion-thermo and thermal-diffusion has been
studied. To obtain the non-dimensional, coupled non-linear momentum, energy and concentration equations, the usual
transformations have been used. The obtained non-dimensional equations have been solved by implicit finite difference
technique. The stability and convergence analysis have been analyzed. From the above analysis, parameters restriction
have been obtained to calculate the converge results. The effects of the various parameters entering into the problem
on the velocity, temperature and concentration are shown graphically. Finally, a qualitative comparison with the
published results is shown in tabular form.
Keywords: Viscoelastic fluid, diffusion-thermo, thermal-diffusion, implicit finite difference method;
5.02
Aerodynamic study of FIFA-approved footballs
Firoz Alam, Harun Chowdhury*, Israt Mustary and Bavin Loganathan School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, 3083, Australia
Abstract
The game of football is worlds most viewed, played and loved sport. Due to increasing technological advancements and demand for performance, the ball manufacturers have been developing new designs progressively since its inception over
100 years ago. A traditional spherical football made of 32 leather panels stitched together in 1970s has become 14
synthetic curved panels thermally bonded without stitches in 2006 and more recently 8 panels thermally bonded in
2010, and again some new designed balls in 2013. Despite being most popular game in the world, no data is available
on aerodynamic properties of recently FIFA approved Adidas Cafusa (thermally bonded 32 panels), Nike Maxim
(stitched 32 panels), Umbro Neo 2 Pro (stitched 14 panels, and Mitre Ultimax (stitched 26 panels) footballs. Hence the
primary objectives of this study are to evaluate aerodynamic performance of these recently introduced balls and compare
their aerodynamic properties. The aerodynamic forces and moments are measured experimentally for a range of wind
speeds in wind tunnel. A field trial using professional players has also been undertaken. The aerodynamic forces and
their non-dimensional coefficients were determined and compared. The players perception was also discussed.
Keywords: football; FIFA; drag; wind tunnel; field trial; flow visualisation.
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5.03
Bio-inspired design: aerodynamics of boxfish
Andrei Kozlov, Harun Chowdhury*, Israt Mustary and Bavin Loganathan and
Firoz Alam School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, 3083, Australia
Abstract
This paper investigates the aerodynamic behavior of a boxfish using both experimental and computational methods. A
scaled up model boxfish was manufactured and tested in RMIT Industrial Wind Tunnel under a range of Reynolds
numbers and yaw angles. The drag, lift and side forces and their corresponding moments were measured simultaneously.
A CAD model of the boxfish was used in CFX FLUENT Computational Fluid Dynamics (CFD) modeling. The CFD
modeling data were validated using the experimental findings. The results indicate that the drag coefficient of a boxfish
is around 0.10 which is significantly lower than current drag coefficient of a passenger car. Hence, a boxfish shape can
be adapted for achieving low drag and energy efficient motor vehicle design.
Keywords:0020 Passenger car; aerodynamic drag; box fish; wind tunnel; yaw angle; CFD.
5.04
Numerical investigation on the delay of boundary layer
separation by suction for NACA 4412
R.