memorial university of newfoundland engi 8926: mechanical
TRANSCRIPT
Memorial University of Newfoundland
ENGI 8926: Mechanical Design Project II
Mini Report #2
Vortex Wind Systems
H.A.W.T Rotor Detailed Design
March 7th, 2014
Dan Follett - 200559359
Scott Guilcher - 200915585
Jeremy Tibbo - 200902690
Group M9
Vortex Wind Systems | March 7th, 2014 i
Table of Contents
Table of Figures ............................................................................................................................................. ii
List of Acronyms ........................................................................................................................................... iii
1.0 Introduction ...................................................................................................................................... 1
2.0 Blade Design Theory ......................................................................................................................... 2
2.1 Blade Element/Momentum Theory .............................................................................................. 2
2.2 Iterative process ............................................................................................................................ 4
2.3 Stall Regulated Turbines ............................................................................................................... 5
2.4 Tapered Blade Design ................................................................................................................... 5
3.0 Airfoil Polar Data Evaluation ............................................................................................................. 5
3.1 Airfoil Selection and Evaluation .................................................................................................... 5
3.2 Airfoil Selection Caveats ............................................................................................................... 6
3.3 Root Airfoil S814 ........................................................................................................................... 6
3.4 Mid-Span Airfoil S812 ................................................................................................................... 7
3.5 Tip Airfoil S813 .............................................................................................................................. 8
4.0 Design Considerations....................................................................................................................... 9
4.1 Betz Law ........................................................................................................................................ 9
4.2 Justification for 3 Blades ............................................................................................................... 9
4.3 Theoretical Blade Length ............................................................................................................ 10
4.4 Theoretical Power Output and Demand ..................................................................................... 11
5.0 Blade Design Analysis ...................................................................................................................... 12
5.1 Geometry .................................................................................................................................... 12
5.2 Performance Analysis.................................................................................................................. 13
5.3 Solid Mechanics .......................................................................................................................... 15
6.0 Moving Forward .............................................................................................................................. 18
7.0 Conclusion ....................................................................................................................................... 19
References .................................................................................................................................................. 20
Vortex Wind Systems | March 7th, 2014 ii
Table of Figures
Figure 1 - Sectional Blade Profile [1] ............................................................................................................. 2
Figure 2 - Vector Configuration [2] ............................................................................................................... 2
Figure 3 - Propeller Disc and Stream Tube Area [1] ...................................................................................... 3
Figure 4 - Slipstream Model [2]..................................................................................................................... 3
Figure 5 - S814 Normalized Profile................................................................................................................ 6
Figure 6 - Coefficient of Lift and Drag Ratio vs. Angle of Attack ................................................................... 7
Figure 7 - S812 Normalized Profile................................................................................................................ 7
Figure 8 - Coefficient of Lift and Drag Ratio vs. Angle of Attack ................................................................... 8
Figure 9 - S813 Normalized Profile................................................................................................................ 8
Figure 10 - Coefficient of Lift and Drag Ratio vs. Angle of Attack ................................................................. 9
Figure 11 - Power Demand Yearly [7][8] ..................................................................................................... 11
Figure 12 - Chord Distribution of Turbine Blade ......................................................................................... 12
Figure 13 - Twist Distribution of Turbine Blade .......................................................................................... 13
Figure 14 - Rotor Power Coefficient for Varying Wind Speeds ................................................................... 14
Figure 15 - Power Curve for Current Wind Turbine Design ........................................................................ 14
Figure 16 - Preliminary Stress Calculation Diagram .................................................................................... 16
Figure 17 – Simplified Blade Dimensions [10] ............................................................................................ 17
Vortex Wind Systems | March 7th, 2014 iii
List of Acronyms
Acronym Meaning
1D One dimensional
2D Two dimensional
3D Three dimensional
HAWT Horizontal Axis Wind Turbine
FEA Finite Element Analysis
Air Density (kg/m3)
Pitch Angle
Difference in Thrust and Lift Direction
Axial Flow Velocity Vector
Sectional Flow of Velocity Vector
Angular Flow Velocity Vector
B Number of Turbine Blades
Change in Momentum Flow Rate
Change in Angular Momentum Rate for Flow x Radius
Lift Coefficient
Drag Coefficient
TSR Tip Speed Ratio
Vortex Wind Systems | March 7th, 2014 1
1.0 Introduction
After performing the Front End Engineering and Design (FEED) work, it became necessary to
evaluate the rotor design of the HAWT in order to continue moving forward in this project. This
report will discuss the detail design of the 500W stall regulated wind turbine blades. The
turbine is to be a robust, reliable and optimal design that would be cost effective for the
application of a small cottage. The reason for targeting the cottage application is an attempt to
supply power to remote, off grid locations. Calculations will be provided in this report to
support the selection of the 500W sizing as the appropriate size turbine to supply sufficient
power to run a radio, television, lights, water pump and potentially fridge as well as water
heater. These are considered basic needs for a cottage and all other larger appliances were left
out of the scope of this project due to the high power demands and ineffectiveness in a cottage
environment.
This report will begin with some background blade design theory. The PropID method of
iteration will be discussed as well as the main theories behind the development of this windows
based program, the blade element and momentum theory.
Using XFLR5 and Prop-ID, Vortex Wind systems was able to design wind turbine blades which
will stall at the regulated power and produce at the average wind speeds found in
Newfoundland for optimal performance. Using XFLR5, the blade airfoils will be first evaluated
then incorporated into PropID to design the optimum blade suitable for the specific design
specifications previously mentioned.
Stress calculations will be provided in this report to gain perspective of what might occur during
future finite element analysis evaluations. Treating the blades as a simple structure, these
calculations are to gain a general idea of what to expect when performing the FEA but are
essential in leading Vortex Wind Systems in the right direction.
This report will discuss why the reasoning behind different design aspects of the blades was
chosen. The reasoning behind the tapered blades, a three bladed turbine design and how the
theoretical blade length was calculated will all be discussed in detail during this report. The
blade design theory section of the report will also describe the iteration method PropID uses to
determine the necessary outputs needed to design the blade.
To conclude the report, Vortex Wind Systems will specify the steps moving forward in the
coming months to ensure the proper closure of the project.
Vortex Wind Systems | March 7th, 2014 2
2.0 Blade Design Theory
2.1 Blade Element/Momentum Theory
In considering our blade design Vortex Wind Systems chose to utilize Prop-ID for the design and
analysis of the turbine blade. Blade element and momentum theory are used in predicting the
performance parameters and are the supporting theories behind the Prop-ID software package.
Blade element and momentum theory involve the division of the blade into multiple sections
while lift, drag, thrust and torque are represented in a two dimensional plane as illustrated in
Figure 1 - Sectional Blade Profile Figure 1.
Figure 1 - Sectional Blade Profile [1]
In addition, axial and angular momentum is applied to the model producing a non-linear set of
relationships.
Figure 2 - Vector Configuration [2]
Vortex Wind Systems | March 7th, 2014 3
By analyzing both circumferential and axial directions, the governing principle behind the
conservation of flow momentum can be analyzed. It is by the consideration of momentum
theory that the change in flow momentum in the axial direction can be observed. This means
that any change in flow momentum observed upstream that subsequently passes through the
blade must in turn equal the thrust produced by this element of the blade. [3]
Figure 3 - Propeller Disc and Stream Tube Area [1]
In an effort to eliminate any unsteady effects resulting from our blades rotation, it is assumed
the horizontal axis wind turbine (HAWT) is covered around its sweep area as shown below in a
slipstream model.
Figure 4 - Slipstream Model [2]
Vortex Wind Systems | March 7th, 2014 4
2.2 Iterative process
Equations [2]
1 -
2 –
3 -
4 -
5 -
6 -
The iterative process that Prop-ID uses to better define various desirable properties begins with
some initial guess inflow factors. These inflow factors are then used to find the flow velocity
and flow angle on the blade as shown in equations 3 and 4. This is then used to determine
blade section properties to in turn estimate the thrust and torque as shown in equations 1 and
2.
With these approximations in place equations 5 and 6 can be used to better define the values
of the initial inflow factors. This process in executed repeatedly until the inflow factors have
converged within an acceptable tolerance.
In using the Prop-ID software package this iterative process can be repeated continually until a
value for both thrust and torque can be predicted for the overall performance.
Some limitations to the theory and through association the software Prop-ID include:
Negates 3D Flow Velocities
Over Predicts Thrust
Under Predicts Torque
Overshoots Actual Efficiency by 5-10%
The objective is to use this software to create comparative results considering environmental
conditions. In turn these comparative results act as a tool to help optimize the blade pitch given
the rated wind speed in addition to optimizing our blade solidity aiding in the material selection
process.
Vortex Wind Systems | March 7th, 2014 5
2.3 Stall Regulated Turbines
Constant-speed, stall-regulated wind turbines have blade designs that passively regulate the
produced power. The fixed-pitch blades are designed to operate near the optimal tip speed and
lift to drag ratio at low wind speeds. When the wind speed increases, the angle of attack
increases and parts of the blade, starting at the blade root, begin to enter the stall region. [4] As
blades move into a stall region they begin to produce less lift, reducing the tip speed and power
output. A stall controlled blade will not spin at excessively high rates and damage the turbine.
This is a main design focus for Vortex Wind Systems.
2.4 Tapered Blade Design
Blades which are designed for optimum power production will have a tapered blade design
with an increasingly larger cross section at the root of the blade and much smaller at the tip of
the blade. The pressure on the suction side of the blade is lower than the pressure side;
therefore the air will flow around the tip from the lower toward the upper side. This reduces
the lift of the blade and decreases the power production near the tip of the blade. With a
tapered blade design moving from a larger cross section at the root, to a smaller cross section
at the tip, these tip loss effects can be reduced [4]. A tapered blade design will be utilized by
Vortex Wind in attempt to maximize the power output.
3.0 Airfoil Polar Data Evaluation
3.1 Airfoil Selection and Evaluation
The properties of incoming wind vary when moving radially along the blade section from root
to tip. That is, the root blade section experiences lower relative wind speeds than the tip due to
its position from the center. The profile of an airfoil dictates the aerodynamic properties of the
blade and is critical in designing and evaluating the turbine. For this reason, the blade is
sectioned into three distinct regions: the root, mid-span, and tip. Three airfoils were selected
for these regions. An analysis of their lift and drag data across varying angle of attacks and a
range of Reynolds numbers were conducted using the XFLR5 program for the integration into
Prop-ID.
Vortex Wind Systems | March 7th, 2014 6
3.2 Airfoil Selection Caveats
It should be noted that Prop-ID requires the lift and drag data to be evaluated up to an angle of
attack of 27.5°. While angles this high may not be present in the design, the program will not
operate without data in this region. As a result, some airfoils cannot be selected as it is not
possible to calculate data with the XFLR5 program. The airfoils selected are recommended for
wind turbines and all reached converged solutions for the required range.
3.3 Root Airfoil S814
The S814 airfoil, shown in Figure 5, is specifically designed to operate in the root region of the
blade. The primary purpose of its design is to create high maximum lift and low drag for the
lower airspeed region. This profile also has a thicker cross-section to provide greater strength to
the blade structure. The profile coordinate data was directly imported into XFLR5 where a
batch analysis was completed to obtain comprehensive lift and drag information suitable for
integration into Prop-ID.
Figure 5 - S814 Normalized Profile
Figure 6 shows the lift and drag ratio for a series of Reynolds numbers across a range of angles
of attack. This plot shows the set of attack angles where the foil can productively capture wind
energy. The pitching moment coefficient plot and a lift versus drag plot for this foil were also
completed and are contained in Appendix A1.
Vortex Wind Systems | March 7th, 2014 7
Figure 6 - Coefficient of Lift and Drag Ratio vs. Angle of Attack
3.4 Mid-Span Airfoil S812
The mid-span section of the airfoil is considered to be the main power generating section of the
blade [4]. Its profile can be seen in Figure 7. A higher lift to drag ratio is desired for the range to
attack angles it is to be operating, this is observed in Figure 8. The pitching moment coefficient
plot and a lift versus drag plot for this foil were completed and are contained in Appendix A1.
Figure 7 - S812 Normalized Profile
Vortex Wind Systems | March 7th, 2014 8
Figure 8 - Coefficient of Lift and Drag Ratio vs. Angle of Attack
3.5 Tip Airfoil S813
The highest relative wind velocities occur in the tip section of the blade. As the relative angle of
attack increases with an increasing wind velocity, this section of the blade experiences the
highest drag forces. Minimizing the effects of drag is the primary consideration for the foil [5].
The profile can be seen in Figure 9 and drag ratio in Figure 10. The pitching moment coefficient
plot and a lift versus drag plot for this foil were completed and are contained in Appendix A1.
Figure 9 - S813 Normalized Profile
Vortex Wind Systems | March 7th, 2014 9
Figure 10 - Coefficient of Lift and Drag Ratio vs. Angle of Attack
4.0 Design Considerations
4.1 Betz Law
Betz Law states that the design can only convert approximately 59% of kinetic wind energy into
mechanical energy. Efficiency is determined by the rotor blade where the maximum efficiency
is maintained at the optimal rotational speed (aerodynamic power coefficient) for the given
blade.
In generators, when converting rotational mechanical to electric energy the resistance to the
rotor provides a form of friction that can only be overcome with a specific start up wind speed
that must be reached to overcome these forces.
Another source of inefficiency is when yawing each blade experiences cyclic loading at its root
depending on its position. These loads combined with the drive train shaft can be balanced
symmetrically for three blades yielding a smoother operation for turbine yaw [4].
4.2 Justification for 3 Blades
In considering the number of blades and the optimization of the model, aerodynamic efficiency,
component costs and system reliability need to be taken into account. Aerodynamic efficiency
increases by 6% [4] when moving from one to two blades, while moving from two to three
blades provides an increase of 3% [4]. Any additional blades beyond three provide minimal
Vortex Wind Systems | March 7th, 2014 10
returns in efficiency. In addition, as the blades would need to be much thinner and unstable
causing interference with the tower; it sacrifices too much blade stiffness when considering
interference with the tower. Adding additional blades would also lead to a higher
manufacturing cost and would decrease the overall rotational speed. Fewer blades with higher
rotational speeds result in reduced peak torques in the drive train lessening the probability of
gearbox and generator failure.
4.3 Theoretical Blade Length
[5]
Power Output – 500W
PC - Power Coefficient (Efficiency of the rotor to convert energy) (35%)
A - Sweep Area of the Blade ( (Units in )
r – Radius of Sweep Area (Units in m)
PA - Power Density of the Wind = 0.6125x (S - Wind Speed in m/s)
G - Generator Efficiency (90%)
With the output and rated wind speed taken from out market analysis, solving for r to get the
following:
r = 1.202 m
This gives an initial guess from which to compare with the Prop-ID model. Appendix A2 contains
detailed calculations.
Vortex Wind Systems | March 7th, 2014 11
4.4 Theoretical Power Output and Demand
In maintaining an average run time of 66%, a theoretical power output both in Watts (W) and
Kilowatt Hours (kWhrs) for the turbine per year can be estimated. This can then be used for
various comparisons. Calculations for the following section are included in Appendix A2.
The yearly kWhrs for Vortex Wind System’s 500W wind turbine is found to be which 2851.2
kWhrs/year at 66% operation time [6]. At this kWhr output a 500W device at this kWhr output
will have 5702.4 hours per year. Taking the hours per year of operation and applying it to a
500W generator at 4.2 liters of fuel for 5.8 hours of operation yields a total of 4129.3 liters per
year [7]. From the current gas prices ($1.35 per liter) it would cost $5,574.00 to run a generator
for the equivalent output per year [8].
These are rough calculations but with an expected life of around twenty years and an estimated
price tag of $500-$1500 as found in the market analysis, the financial benefits of using a
horizontal axis wind turbine add the primary source of energy are evident even during the first
year.
Considering power consumption, the daily kWhr usage rates for the appliances below for the
associated average usage length trends are provided [8] [9].
Figure 11 - Power Demand Yearly [7][8]
It can be seen from the above summation that at 26.4 kWhrs per day for 52 weekends per year
that the 2745.6 kWhrs/year power demands falls just below the estimated output of 2851.2
kWhrs/year.
Vortex Wind Systems | March 7th, 2014 12
5.0 Blade Design Analysis
5.1 Geometry
The variables assessed for the geometric design and optimization within Prop-ID are: rotor
diameter, chord length, twist and pitch. An initial geometry with preliminary values was
entered as a starting point for the programs iteration methods. To perform the analysis, a
preliminary design point was specified. The required 500W output with a target wind speed of
7m/s was used. Using data from the market analysis, the HAWT was set to operate at 300 rpm,
comparable to existing designs. Aerodynamic data calculated from the family airfoils discussed
was integrated into Prop-ID. The S814 airfoil was set to exist at the first 30% of the blade
length, S812 from 30% to70%, and S813 for the remainder of the blade. Applying this design
point to the base geometry, with the integrated foil data, Prop-ID functions were executed to
manipulate the rotor radius, and chord lengths to reach the specified design point.
Prop-ID concluded that the optimal rotor radius to meet the design point with the given airfoil
data was 4.3 feet. This is a realistic result as the simplified initial calculations expected a radius
of 3.9 feet. Figure 12 illustrates the optimized chord length across the new length of the blade.
This plot shows the tapering of the chord expected of this type of airfoil.
Figure 12 - Chord Distribution of Turbine Blade
Vortex Wind Systems | March 7th, 2014 13
Figure 13 (twist distribution for the blade) follows the typical profile for a stall regulated
turbine; however, these angles need further optimization as the functions for this procedure
have not yet been successfully run. The twist angles shown represent a typical distribution of
this class of turbine [5] Input and output geometry files can be seen in Appendix 3.
Figure 13 - Twist Distribution of Turbine Blade
5.2 Performance Analysis
From the results of the geometric analysis, the 2D-Sweep and 1D-Sweep functions were used to
perform an analysis on the rotor performance and aerodynamic characteristic of the blade.
Figure 14 shows that the maximum rotor power coefficient of 46% to occur at 5.6m/s and the
target wind speed of 7 m/s to have an efficiency of 39%. Ideally the peak efficiency should
occur at the target wind speed to maximize the energy captured as wind at 5 m/s does not hold
a significant amount of harvestable energy as illustrated in the Power Curve of Figure 15.
Vortex Wind Systems | March 7th, 2014 14
Figure 14 - Rotor Power Coefficient for Varying Wind Speeds
The target is to design the blades to produce 500W at a wind speed of 7 m/s, but the turbine
has an estimated 497 W peak power production at 9.8 m/s. At 7m/s it is estimated that power
production is 415W, 17% lower than required. Further optimization of the design parameters
will be necessary to shift the power curve into the correct position. It is evident that after peak
power is reached, power efficiency and production decrease as wind speeds continue to
increase – this is the result of stall regulation. The power curve does continue to climb but does
not achieve comparable production at high wind speeds.
Figure 15 - Power Curve for Current Wind Turbine Design
0.000
0.100
0.200
0.300
0.400
0.500
0 5 10 15 20 25 Ro
tor
Po
we
r C
oe
ffic
ien
t
Wind Speed (m/s)
Cp vs. Wind Speed
Vortex Wind Systems | March 7th, 2014 15
The tip speed ratio (TSR) is the fraction between the tip speed of the blade and the wind speed.
The TSR versus rotor power coefficient plot shows the range of tip speeds observed by the
blade. Peak efficiency is achieved with a tip speed ratio 6.98 but values of as high as 15 are
seen. Values above 10 are considered high and consideration should be given to centripetal
effects and potential fouling of the blade at the leading edge. Further optimization should
attempt to reduce high TSR values and minimize any detrimental effects.
5.3 Solid Mechanics
Before performing a finite element analysis (FEA) on the actual blade design, it was decided to
perform preliminary stress calculations. This is to gain an approximate estimate of values and to
give a starting point for the finite element analysis evaluation which will be performed in the
coming months. The first step to finding a rough maximum stress value is calculating the lift and
drag forces that will occur on the blade. The maximum coefficient of lift (CL) as specified from
Prop-ID is 1.6 while the maximum coefficient of drag (Cd) was found to be 0.39. These values
are directly proportional to their respective lift and drag forces. The lift and drag forces were
solved using the following formulas:
(Lift Force per unit length) [4]
(Drag force per unit length) [4]
Where:
Ρ = density of air (1.225 kg/m3)
U = wind speed (12.5 m/s)
c = chord length (0.22552 m)
This yielded the following lift and drag forces:
The blade has been modeled as a uniform beam cross section which is fixed at one end as
shown in Figure 16Figure 16. Using the distributed loads (Lift and Drag) previously calculated we
can gain a rough estimate of the stresses at the root of the blade. The width and height values
of the beam simulate the initial size of a spar like beam which will run the length of the beam to
Vortex Wind Systems | March 7th, 2014 16
act as support for the outer layer. Here it is assumed that this beam will take all of the force
due to lift and drag.
Figure 16 - Preliminary Stress Calculation Diagram
Two moments will occur in this stress evaluation. A moment will occur about the Y-axis in a
negative manner, while a second moment will occur about the Z- axis in the positive direction.
These are calculated by:
This yields a Mz = 7.16 Nm and My = -29.38 Nm. Now the moments the maximum stress can be
evaluated using the simplified equation below:
Solving this expression yields a maximum stress of 1.297 MPa. Using similar equations, an
analysis was performed in the event the blades are parked and winds reach 160 km/h. Here the
blades were assumed to be flat plates with the wind acting perpendicular to the blade surface.
The maximum stress at this point was found to be 18.4 MPa. This will be the value we will
use moving forward as it is worst case scenario and Vortex Wind Systems believes that
Vortex Wind Systems | March 7th, 2014 17
designing to suit these stress values will provide safe operation of the turbine. For more
information on these calculations please refer to Appendix A2.
It is also important to understand the centripetal force. This is an external force that is required
to make a body follow a curved path. This force acts inwards, towards the centre of curvature
of the path. Figure 17 shows the simplified blade dimensions used in this analysis.
Figure 17 – Simplified Blade Dimensions [10]
The centripetal force can be calculated by:
[10]
The area will be an estimation of the area of the airfoil at the root section of the blade. The
rotations per minute (rpm) used is the design rpm which will be the maximum. This is to gain
rough estimate of values and to give a starting point for the finite element analysis evaluation
which will be performed in the coming months. In this case:
A = 1.17x10-2 m
ρ = 1.225 kg/m3
r2 = 1.46 m
r1 = 0.15 m
= 31.41 rad/s
Vortex Wind Systems | March 7th, 2014 18
This gives a centripetal force of the blade is found to be F = 14.9 N. So as stated previously the
force due to max winds and assuming the blades are stationary will be used to move forward
with a rough estimate to begin FEA.
6.0 Moving Forward
At this point, Vortex Wind Systems is ready to move forward to the final section of the Detailed
Design phase which consists of the design of the various components needed for the
prototyping and testing of the turbine. It has been decided that testing will be done at a scaled
version of the actual design and tested in the wind tunnel provided for student use at Memorial
University of Newfoundland. In order for the testing to be completed the following components
will need to be fabricated:
Turbine Blades (3)
Shaft to connect blades to generator
Turbine main frame
Rotor hub
Design analysis will be conducted for the design of the shaft to ensure that it can withstand the
expected forces during testing. However a detailed finite element analysis will not be
performed due to time constraints. The top priority of the project is the design of the blades, so
a finite element analysis will be performed moving forward to select an appropriate material
for the blades. The following components will be bought and will not be designed in the same
manner as the previous items:
Generator
Bearings for shaft
After the design of the prototype, testing will be conducted and the final report will summarize
the work performed throughout the entire project as well as the work done in testing to
compare the theoretical power curve as found in PROP-ID and the power curve found during
testing exercises.
Vortex Wind Systems | March 7th, 2014 19
7.0 Conclusion
Due to the inexperience of using Prop-ID, the learning curve proved to be more complex than
initially expected. However with persistence, Prop-ID and XFLR5 have been used to develop an
initial blade design that we can now evaluate and continue optimizing if necessary. Vortex Wind
solutions is content with the power curve produced and it is believed that this can be optimized
if need be. It is now important to compare the power curve produced to other curves in the
industry to assess whether or not the design goal of producing more power than competitors
with Newfoundland wind trends was achieved.
Vortex Wind Systems has now made initial stress calculations and will now continue on to
ensure the strength of the blades by performing a thorough finite element analysis. The
maximum stress that will be used as a starting point for selecting material will be 18.4
MPa, which was calculated at wind speeds of 160 km/h and assuming the blades were acting as
flat plates with the wind force acting perpendicular to the surface. This would be a rare case
but to ensure the safety and reliability of the blades it has been decided to move forward with
this value.
As described in the report the blade consists of a tapered cross section to limit the tip loss
effects on the blades. Also three blades were chosen to optimize the efficiency of the turbine.
Now that the detailed design is completed, prototyping, testing and finite element analysis of
the blades will be carried out in the next month of the project. A large portion of detail will be
put forward in the finite elemet analysis as the blades are the main focus of this design process.
At this point Vortex Wind Systems has remained on schedule according to the project
management plan and will attempt to remain this way for the last month of the project.
Vortex Wind Systems | March 7th, 2014 20
References
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Anadolu University, School of Civil Aviation , 2004. [Online]. [Accessed 2014].
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http://www-
mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/propeller/prop1.html.
[3] D. D. Symons,
"http://www2.eng.cam.ac.uk/~hemh/climate/P8_Blade_Design_Student_Handout_2009.pdf
," [Online]. [Accessed 2014].
[4] J. F. Manwell, J. G. Mcgowan and A. L. Rogers, Wind Energy Explained 2ed, Chichester: John
Wiley & Sons Ltd., 2009.
[5] J. McCosker, "Design and Optimization of a Small Wind Turbine," Rensselaer Polytechnic
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209804414/Mini_portable_gasoline_generator_500w_4_stroke_with_CE_ISO_EPA.html.
[Accessed 2014].
[8] "Concordia Electric Cooperative Inc," [Online]. Available:
http://www.concordiaelectric.com/forms/kWh_Usage.pdf. [Accessed 2014].
[9] "Festival Hydro," [Online]. Available:
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[10] T. R. A. o. Engineering, "Forces on Large Steam Turbine Blades," [Online]. Available:
https://www.raeng.org.uk/education/diploma/maths/pdf/exemplars_advanced/22_Blade_F
orces.pdf. [Accessed 2014].
Vortex Wind Systems | March 7th, 2014 21
[11] "Flap Turbine," [Online]. Available: http://www.flapturbine.com/how_many_blade.html.
[Accessed 2014].
[12] "Newfoundland Gas Price," [Online]. Available: http://www.newfoundlandgasprices.com/.
[Accessed 2014].
Vortex Wind Systems | March 7th, 2014 iV
Appendix A1
Figure A2.1 - Cl Vs. Alpha S812
Figure A2.2 - Cl Vs. Alpha S813
Figure A2.3 - Cl Vs. Alpha S814
Figure A2.4 - Cl Vs. Cd S812
Figure A2.5 - Cl Vs. Cd S813
Figure A2.6 - Cl Vs. Cd S842
Figure A2.7 - Cm Vs. Alpha S812
Figure A2.8 - Cm Vs. Alpha S813
Figure A2.9 - Cm Vs. Alpha S814
Figure A2.9 – Cl Vs. Alpha Prop-ID Blade Segments
Vortex Wind Systems | March 7th, 2014 V
Appendix A2
Vortex Wind Systems | March 7th, 2014 Vi
Appendix A3
PROP-ID Input file # Stall Regulated Turbine 500W Input File # Basic input MODE 1.0 # wind turbine INCV 0.0 # wind turbine mode LTIP 1.0 # use tip loss model LHUB 1.0 # use hub loss model IBR 1.0 # use brake state model ISTL 1.0 # use viterna stall model USEAP 1.0 # use swirl suppression WEXP 0.0 # boundary layer wind exponent NS_NSEC 10.0 1.0 # number of blade elements/number of sectors IS1 1.0 # first segment used in analysis IS2 10.0 # last segment used in analysis BE_DATA 1 # printout blade element data SH 0.0 # shaft tilt effects RHO 0.0023769 # air density (slug/ft^3) # Geometry HUB 0.04 # normalized hub cutout HH 3.333 # normalized hub height BN 3 # blade number CONE 0 # cone angle of rotor (deg) RD 4.279492 # radius(ft) CH_TW # Normalized chord and twist distribution 0.172918 13.0000 0.155626 8.0000 0.103751 6.0000 0.086459 6.0000 0.064258 4.0000 0.056225 1.0000 0.064258 -1.0000 0.056225 -3.0000 0.048193 -4.0000 0.043229 -5.0000 AIRFOIL_MODE 4 4 s814.pd .24 13. 3 1.600 6 s814.pd .24 13. 3 1.600 6 s812.pd .21 14.3 3 1.180 6 s813.pd .16 9. 3 1.100 6
# airfoil family 1 with 2 airfoils # r/R-location and airfoil index AIRFOIL_FAMILY 4 0000 1 .3000 2 .7500 3 1.0000 4 USE_AIRFOIL_FAMILY 1 # Enforce tip loss model to always be on TIPON # Use the Prandtl tip loss model, # not the original modified model. TIPMODE 2 # Design point: 300rpm, 2 deg pitch, 16 mph DP 1 300 2 16 2 #Specify the peak power (500W) and iterate on the rotor scale NEWT1ISWP 300 0.50 1 40 .1 1 1 999 1 7 999 .3 IDES # Specify the peak power (500W) and iterate on the chord #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 2 1 999 .05 #IDES #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 3 2 999 #IDES #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 3 3 999 #IDES #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 3 4 999 #IDES #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 3 5 999 #IDES #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 3 6 999 #IDES #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 3 7 999 #IDES #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 3 8 999 #IDES #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 3 9 999 #IDES #NEWT1ISWP 300 0.5 1 25 .1 1 1 999 3 10 999 # Initiate design (does some required preliminary work before analysis) #IDES
# Determine the rotor power, Cp, and thrust curves (2D_SWEEP) # # use pitch setting from design point (DP) 1 PITCH_DP 1 # use rpm from design point (DP) 1 RPM_DP 1 # sweep the wind from 5 to 50 mph in increments of 1 mph WIND_SWEEP 1 50 1 2 # perform the sweep 2D_SWEEP # write out data to files # 40 - power curve (kW) vs wind speed (mph) # 45 - Cp vs TSR # 51 - rotor thrust curve WRITE_FILES 40 45 51 # Compute the gross annual energy production # Output the data to file: gaep.dat # # Initial avg wind speed - 14 mph # Final avg wind speed - 18 mph # Step - 2 mph # Cutout - 45 mph # # 100% efficiency # GAEP 14 16 .2 45 # # 15 mph only, 85% efficiency GAEP 14 16 1 45 .85 Report_Start # Report the last GAEP analysis case REPORT_SPECIAL 8 999 999 REPORT_END # Obtain aero distributions along the blade (1D_SWEEP) # PITCH_DP 1 RPM_DP 1 WIND_SWEEP 5 30 5 2 1D_SWEEP # write out # 75 - blade l/d dist # 76 - blade Re dist # 80 - blade alfa dist # 85 - blade cl dist # 90 - blade a dist WRITE_FILES 75 76 80 85 90
# Write out # 95 - chord dist (ft-ft) # 99 - alfa dist (ft-deg) WRITE_FILES 95 99 #REPORT_BE_DATA 14 0 #REPORT_BE_DATA 14 .25 #REPORT_BE_DATA 14 .5 #REPORT_BE_DATA 14 .75 # Write out the rotor design parameters to file ftn021.dat DUMP_PROPID *
Prop-ID Geometry Output File RHO 0.002377 HUB 0.034584 RD 4.279492 CH_TW 0.172918 13.0000 0.155626 8.0000 0.103751 6.0000 0.086459 6.0000 0.064258 4.0000 0.056225 1.0000 0.064258 -1.0000 0.056225 -3.0000 0.048193 -4.0000 0.043229 -5.0000 AIRFOIL_MODE 4 4 s814.pd 0.240 13.000 3.000 s814.pd 0.240 13.000 3.000 s812.pd 0.210 14.300 3.000 s813.pd 0.160 9.000 3.000 AIRFOIL_FAMILY 4 0.0000 1 1.0000 0.3000 2 0.7000 0.7500 3 0.2500 1.0000 4 0.0000 USE_AIRFOIL_FAMILY 1 DP 1 250.0000 2.000 16.000 2