1 avc gollege of engineering. mannampandal. department of mechanical engineering
TRANSCRIPT
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AVC GOLLEGE OF ENGINEERING.MANNAMPANDAL.
DEPARTMENT OF MECHANICAL ENGINEERING
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VIBRATION ANALYSIS OF DOUBLE IMPELLER MARINE PUMP USING FEA METHOD
GUIDED BY PRESENTED BY Mr.S.VIJAYARAJ.M.E., P.J SENTHIL KUMARASST.PROFESSOR, R.NATARAJANDEPT OF MECHANICAL ENGG T.BALAKRISHNAN K.JEGADESH
COMPANY PROFILE COMPANY NAME : MACRO ENGINEERING
PVT LTD PLACE : CHENNAI.
YEAR OF ESTABLISHED: 2003
PRODUCT DESCRIPTION :DESIGN & ANALYSIS
PUMPS
On the basis of transfer of mechanical energy, the pumps can be broadly classified as,
Positive displacement Pumps Roto dynamic Pumps The centrifugal pump of today is made by
250 years old evolution. It has now attained a new degree of
perfection It is widely used as it can be coupled directly to electric motors, steam turbines etc.
DOUBLE IMPELLER MARINE PUMP
It is a contrivance to boost up liquids in the pipe line by creating the required pressure with the help of centrifugal action.
In general it can be defined as a machine which increases the pressure energy of a fluid, as a pump may not be used to lift water at all, but just to boost the pressure in a pipe line
MARINE PUMP
APPLICATIONS To pump the salt water from sea to ship
for process. To boost up the working fluid between
two tanks To pump the back water in the seashore. To pump the water in power plant
industries.
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PROBLEM DESCRIPTION Vibration is the major problems of all machines
and rotating components. In marine pumps It affects the over all efficiency of the pump. Prevention and control of vibrations in pumps is more important point to increase the efficiency of the marine pumps. So it is necessary to find out the vibrations during its operating condition.
Determination of the stress and deformation of the already designed double impeller marine pump due to vibrations in the pump if any as prevention control of vibration of machines structure is an important design consideration.
For this reason, capacity, head, power consumption are the essential points in double impeller marine pump design.
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METHODOLOGY
MODELLING – PRO-E WILD FIRE 3.0
MESHING - HYPERMESH 9.0
ANALYSIS - ANSYS 10.0
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HARDWARE AND SOFTWARE DESCRIPTION:
The following virtual validation is carried on the following hard ware
Hardware: HP xw8200 Workstation Processor-Two 64-bit Intel® Xeon™
processor(s) with Hyper-Threading Technology
Memory-7 GB of ECC DDR2 400 MHz SDRAM
Graphics-NVIDIA Quadro FX 1400 (PCIe)
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Software: Preprocessing : Hypermesh9.0 Solver : ANSYS 10.0 Post processing : ANSYS 10.0
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INTRODUCTION OF FEA Finite element analysis is a process, which can be
used to predict deflection and stress on a structure. In finite element model, the structure is divided in to
number of grids, which is called as elements. Each of the elements has a simple shape (such as
square or triangle) for which the finite element program has information to write the governing equations in the form of stiffness matrix for the entire model.
This stiffness matrix is solved for the unknown displacements at the nodes, the stresses in each element can be calculated.
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INTRODUCTION OF FEA
The finite element is derived by assuming a form of the equation for the internal strains.
The equilibrium equation between the external forces and the nodal displacements can be written.
There will be one equation for each degree of freedom for each node of the element.
The equation is [K] [U] = [F]
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OBJCTIVE OF THE PROJECT
Build a detailed finite element model of the impeller assembly
Carry out a static Analysis with a single time step
Dynamic analysis with response spectrum behavior using corrugated load case.
INPUT DATA
CAD data: 3D Models of pump impeller and the assembly files of ProE wildfire3.0
Loading, boundary conditions and material properties as available in FIAT-GM Power train Italia standards.
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METHODOLOGY The model of marine pump was designed
by using pro-E software . The designed part assembly is saved as in
IGES format The IGES file was imported to hyper mesh . Now the assembled model is ready to be
used with hyper mesh for meshing The IGES format meshed model is
imported to ansys for taking analysis.(static & Dynamic
PRO-E MODEL PUMP
SIDE VIEW OF MARINE PUMP
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SPECIFICATIONS OF MARINE PUMP
Pump size 6”
Pump type Radial flow
Pump speed (n) 1470 rpm
No. of stages (N) 2 stages
Discharge (Q) 114 kg/s
Actual head (H) 105 m
Motor rating 200 KW
Motor type Wet
Voltage 415v
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Shaft And Impeller Assembly
STEPS INVOLVED IN MESHING Model input Problem definition Geometry cleanup Element shape No. of nodes and elements Meshing Preview of meshing Checking of quality index
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Material & Loads:
MaterialYoung’s Modulus
DensityPoisson
Ratio
Yield stressσy
Kgf/mm2 g/cc Kgf/mm2
YST310 21000 7.85 0.3 45.0
LOAD Speed = 1470rpmAngular Velocity = 2x3.14x1470/60
= 153.86 rad/sec
STATIC ANALYSYS
Deformation-mm
Usum - Shaft Ux – Impeller and Shaft
Deformation-mm
Uz – Impeller and ShaftUy – Impeller and Shaft
Deformation-mm
Ux – ImpellerUsum – Impeller
Deformation-mm
Uz – ImpellerUy – Impeller
Deformation-mm
Usum – Shaft Ux – Shaft
Deformation-mm
Uy – Shaft Uz – Shaft
Stress-Kgf/mm^2
Principle Stress – Shaft
Stress-Kgf/mm^2
Von Mises Stress – ImpellerVon Mises Stress – Impeller
Part Deformation-mmUsum Ux Uy Uz
Shaft 0.06861
0.264e-3
0.06861
0.926e-3
Impeller
3.94 0.1277 3.939 3.872Note: Usum, Ux, Uy, Uz are
Resultant deformation & deformation in X, Y & Z direction.
DYNAMIC ANALYSYS
MODAL ANALYSIS Frequency - Hz
1st Freq – Hz - Shaft 2nd Freq - Hz- Shaft
Vertical Bend - Shaft Vertical Bend - Shaft
2nd Freq – Hz - Shaft 3rd Freq - Hz- Shaft
Z- Bend - Shaft Vertical Bend - Shaft
4th Freq – Hz - Shaft 5th Freq - Hz- Shaft
Z- Bend - Shaft Local Bend - Shaft
6th Freq – Hz - Shaft 1st Freq – Hz- Impeller & Shaft
Local Bend - Shaft Vertical Bend - Shaft
4th Freq – Hz- Impeller & Shaft 5th Freq – Hz- Impeller & Shaft
Vertical Bend - Shaft Z Bend - Impeller
6th Freq - Hz
Twist - Impeller
MODAL ANALYSIS RESULTS FOR 6 MODES
FREQUENCY HZ Deformation mm minimum
Deformation mm maximum
162.796 1.878 mm 16.904
162.796 1.878 mm 16.904
435.475 -11.466 15.34
435.475 -11.466 15.34
775.88 8.765 78.885
775.88 8.765 78.885
MODAL ANALYSIS RESULTS
In modal analysis results the above following we find, various set of frequencies for shaft with impeller at a speed of 1470 rpm. The frequency ranges from 162.796 to775.88. It does not exceed 1KH .
The deformation value is not getting increased beyond
78.885mm with higher frequencies than 775.88Hz Hence the obtained range of vibrations is lesser
So that, the performance of the pump will not affected by vibrations.
Deformation – Usum Deformation – Ux
HARMONIC RESPONSE ANALYSIS Deformation Plot
Deformation – Uy Deformation – Uz
HARMONIC RESPONSE ANALYSIS Deformation Plot
Deformation – Usum - Shaft Deformation – Uy - Shaft
HARMONIC RESPONSE ANALYSIS Deformation Plot
Equivalent Stress - Shaft Equivalent Stress - Shaft
HARMONIC RESPONSE ANALYSIS Stress Plot
Equivalent Stress - Impeller Equivalent Stress - Impeller
HARMONIC RESPONSE ANALYSIS Stress Plot
Part Stress- kgf/mm^2
Shaft 0.0072
Impeller 0.01712
Yield Stress 45
FOS 2.628
Part Deformation-mm
Usum Ux Uy Uz
Impeller + Shaft
0.411e-3 0.845e-4 0.411e-3 0.206e-5
Note: Usum, Ux, Uy, Uz are Resultant deformation & deformation in X, Y & Z direction.
Note: σe – Stress Based on Energy theory (Von Misses Theory);
FOS = σy / σeDesign FOS 2.00< 2.628
Hence the design is safe in Dynamic load
RESPONSE ANALYSIS
0.00E+00
1.00E-03
2.00E-03
3.00E-03
4.00E-03
5.00E-03
6.00E-03
7.00E-03
8.00E-03
9.00E-03
1.00E-02
0 50 100 150 200 250 300 350
FREQ
AM
PL
ITU
DE
MASS-1
MASS-2
HARMONIC RESPONSE ANALYSIS Frequency – Hz Vs Amplitude -mm
Conclusions:
From the foregoing FE analyses & results, the following conclusions are
drawn.
The result of static analysis under the self weight + speed (1470rpm) are tabulated. It is seen that maximum
stresses in the impeller notch.Maximum stresses are within material yield, Design FOS = 2.0, Minimum
factor of safety is 2.14.
In the dynamic analysis the frequencies ranges from 124.42Hz to 775.88Hz. It does not exceed 1 kHz. So the Obtained frequencies during the analysis are within the limit.
Hence the obtained range frequency of vibrations is less. So that, the performance of the pump will not be affected by vibrations.
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Finally the design is found to be safe from the static and dynamic conditions are well
within material yield and meet the design requirements. The analysis is carried out using
ANSYS software.
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THANK YOU