Wind turbine simulation
Hi folks,
I have a problem about the rotating simulation of wind turbine. I usually use the RFR or MFR to simulate rotating of fan, but in the wind turbine case the wind flow work is done on the blades to make the blades rotating. In the RFR or MFR case, the rotating rate is applied to simulate the rotating of the blades.In the wind turbine case, I only have the data of wind flow at 6 m/s. How do I simulate the wind flow work is done on the blades and then blades rotating? Thanks! |
Re: Wind turbine simulation
Hi Saturn,
The inlet boundary condition can be specified in the stationary frame. You could make the rotation rate a function of the torque on the blades by inserting a CEL expression for the dynamics. Regards, Robin |
Re: Wind turbine simulation
Hi Robin,
You mean that I can use the velocity inlet boundary condition to specified the wind velocity in the stationary frame. And then I use CEL to specify the rotation rate as the function of the torque. When the solver caculate the torque on the blade ,it will get a rotation rate with this torque. Thanks for your reply! Regards, Saturn |
Re: Wind turbine simulation
Yes. However, on second thought, it might be better just to specify the rotation rate of the wind turbine. If it's connected to a generator, the speed will be fixed.
-Robin |
Re: Wind turbine simulation
Hi,
I too wanted to carry out analysis work on wind turbine. But due to lack of geometry availability i was unable to carry out. If you can share the geometry details it will be very helpfull. my mail-id is rsan_2001@rediffmail.com with regards San |
Re: Wind turbine simulation
please tell me, how to calculate torque by fluen
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Re: Wind turbine simulation
Hi, I will calculate the power out put of my wind turbine simulation in Fluent, but i don't know how to find out the torque in fluent menu bar. Please help my problem. thanks
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Re: Wind turbine simulation
Hi, Verdy
I use CFX 10.0 to caculate the torque on the blade. You can find the torque function in the CFX-Post Tool tab. I ever used FLUENT to simulate the fan. You can use the force report in the main menu. Please visit the following link. http://www.cfd-online.com/Forum/flue...cgi/read/29638 |
Re: Wind turbine simulation
What geometry are you interested in? The most well-known in literature and acadamia is the NREL Phase VI experiment.
This link should give you everything you need. http://wind.nrel.gov/amestest/ |
output shaft power calculation for wind turbine
hi all
Anybody know how to calculate shaft power output for wind turbine in CFX.,because if we take single blade with periodic section i got power(p= T*rpm) for 1 blades & to get power for total turbine i have to multiply that torque by no. of blads.i.e as per CFX power is increasing two times for two blades and three times for three bladses and so on . but in actual wind turbine when we go form 1 blade to 2 blades power increases about 10 % & not double & frm 2 blades to 3 blades power increases about 5 % & not three times. Also , power extracted by turbine= 1/2 *rho*swept area*Cp*V^3 But in this formula how to calculate Cp is the question & way of calculation of CFX is very diffrent from actual case. so how to calculate shaft power for wind turbine in CFX with correct approach |
Hi,
But assuming each blade is equally loaded then the total power is simply n times the power of one blade, regardless of how much power additional blades actually add. Also you may find the turbo machinery macro in CFD-Post useful in post-processing this. Glenn Horrocks |
hi
Glenn Horrocks thaks for reply u r saying right that each blade is equally loaded then the total power is simply n times the power of one blade, regardless of how much power additional blades actually add but in actual wind turbine experimental data shows that it is not the case. in actual wind turbine, from two blades to three blades power increses up to 5 % & not n times of the blade. here Cp = power output / power availabe in wind power availble = (1/2 *rho*swept area*V^2) = 160 kw if power increases n times with no of blades then suppose no. of blade (n) = 1 , then power output = 30 kw n = 2 power output = 60 kw n = 3 power output = 180 kw but the max.theoritical possible value for Cp = 0.59 but in my case if i go for 3 blades then my Cp= 1.12 which is not possible |
No, that is not what I am saying at all. Please read my original post again carefully.
Glenn Horrocks |
hi
Glenn Horrocks thanks for your reply again, I would like to rephrase my question. As per wind turbine theory, the max efficiency of a turbine can reach upto 60%, and experiments suggest that the increase in efficiency from 1 blade to 2 blades is 10% and 2 to 3 is 5%. I have carried out CFD analysis on a single blade (using periodic BC for 3 blades), which gives a power output of 30KW and if i use CFX template or any other guidelines of turbo machinery, the power generated by the three blades would be 30KW*3 = 90KW (which is above theoretical limit of 60% and as per experiments, the power does not get multiplied n times), so where i am going wrong? or is there some misunderstanding in the theoretical and experimental data? I have checked the Power Vs RPM graph from CFD and it looks logical, I have even verified by reducing the wind speed to 50%, and the power output was 1/8th which is as per theory... Your help will be highly appreciated. With Regards, Suraj |
Hi guys!
in your simulations, please have in mind that a wind profile should be considered. So, when the blade is rotating and is pointed to the ground it is not so loaded as when is pointed to the "sky". You cannot consider that the 3 blades are equaly loaded - a windshear should be applied. |
Hi guys!
in your simulations, please have in mind that a wind profile should be considered. So, when the blade is rotating and is pointed to the ground it is not so loaded as when is pointed to the "sky". You cannot consider that the 3 blades are equaly loaded - a windshear should be applied. cheers |
Windturbine
Hi Saturn, I want to make a windturbine simulation. I did the blade with solidworks, What program you use for make the mesh? I have de blade in format .igs but I donīt know how introduce it.
Thank you. |
Hi,
You can import the IGES into Designmodeller (or solidworks) and make a solid region. Then take the solid region into Workbench and mesh it in Simulation. Glenn Horrocks |
Use parasolid files (*.x_t files). I had problems with iges files, when i opened the file in CFX Mesh to mesh in geometries with 10 or 1 micron-millimeter.
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Wind turbine boundary conditions
Hi all,
i am simulating wind turbine ,but here converging problem,any body verify my boundary conditions,is it i was given correct or not. Setting up CFX Solver run ... +--------------------------------------------------------------------+ | | | CFX Command Language for Run | | | +--------------------------------------------------------------------+ LIBRARY: CEL: EXPRESSIONS: dt = 0.04 [s] END END MATERIAL: Air Ideal Gas Material Description = Air Ideal Gas (constant Cp) Material Group = Air Data, Calorically Perfect Ideal Gases Option = Pure Substance Thermodynamic State = Gas PROPERTIES: Option = General Material ABSORPTION COEFFICIENT: Absorption Coefficient = 0.01 [m^-1] Option = Value END DYNAMIC VISCOSITY: Dynamic Viscosity = 1.831E-05 [kg m^-1 s^-1] Option = Value END EQUATION OF STATE: Molar Mass = 28.96 [kg kmol^-1] Option = Ideal Gas END REFERENCE STATE: Option = Specified Point Reference Pressure = 1 [atm] Reference Specific Enthalpy = 0. [J/kg] Reference Specific Entropy = 0. [J/kg/K] Reference Temperature = 25 [C] END REFRACTIVE INDEX: Option = Value Refractive Index = 1.0 [m m^-1] END SCATTERING COEFFICIENT: Option = Value Scattering Coefficient = 0.0 [m^-1] END SPECIFIC HEAT CAPACITY: Option = Value Specific Heat Capacity = 1.0044E+03 [J kg^-1 K^-1] Specific Heat Type = Constant Pressure END THERMAL CONDUCTIVITY: Option = Value Thermal Conductivity = 2.61E-2 [W m^-1 K^-1] END END END END FLOW: SOLUTION UNITS: Angle Units = [rad] Length Units = [m] Mass Units = [kg] Solid Angle Units = [sr] Temperature Units = [K] Time Units = [s] END SIMULATION TYPE: Option = Transient EXTERNAL SOLVER COUPLING: Option = None END INITIAL TIME: Option = Automatic with Value Time = 0 [s] END TIME DURATION: Option = Total Time Total Time = 300.0*dt END TIME STEPS: Option = Timesteps Timesteps = dt END END DOMAIN: rotordisc Coord Frame = Coord 0 Domain Type = Fluid Fluids List = Air Ideal Gas Location = turbine Assembly,turbine Assembly 2 BOUNDARY: discback Side 1 Boundary Type = INTERFACE Location = DISKOUTLET,DISKOUTLET 2 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: frontdisc Side 2 Boundary Type = INTERFACE Location = DISKINLET,DISKINLET 2 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: outerdisc Side 1 Boundary Type = INTERFACE Location = SHROUD 2,SHROUD BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: per1 Side 1 Boundary Type = INTERFACE Location = PER1 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: per1 Side 2 Boundary Type = INTERFACE Location = PER2 2 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: per2 Side 1 Boundary Type = INTERFACE Location = PER1 2 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: per2 Side 2 Boundary Type = INTERFACE Location = PER2 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: rotordisc Default Boundary Type = WALL Frame Type = Rotating Location = BLADE,BLADE 2,HUB,HUB 2 BOUNDARY CONDITIONS: WALL INFLUENCE ON FLOW: Option = No Slip END END END DOMAIN MODELS: BUOYANCY MODEL: Option = Non Buoyant END DOMAIN MOTION: Alternate Rotation Model = On Angular Velocity = 71.9 [rev min^-1] Option = Rotating AXIS DEFINITION: Option = Coordinate Axis Rotation Axis = Coord 0.3 END END MESH DEFORMATION: Option = None END REFERENCE PRESSURE: Reference Pressure = 1 [atm] END END FLUID MODELS: COMBUSTION MODEL: Option = None END HEAT TRANSFER MODEL: Fluid Temperature = 283.15 [K] Option = Isothermal END THERMAL RADIATION MODEL: Option = None END TURBULENCE MODEL: Option = SST END TURBULENT WALL FUNCTIONS: Option = Automatic END END INITIALISATION: Coord Frame = Coord 0 Frame Type = Rotating Option = Automatic INITIAL CONDITIONS: Velocity Type = Cylindrical CYLINDRICAL VELOCITY COMPONENTS: Option = Automatic with Value Velocity Axial Component = 10 [m s^-1] Velocity Theta Component = 0 [m s^-1] Velocity r Component = 0 [m s^-1] END K: Fractional Intensity = 0.05 Option = Automatic with Value END OMEGA: Option = Automatic END STATIC PRESSURE: Option = Automatic with Value Relative Pressure = 101325 [Pa] END END END END DOMAIN: tunnel Coord Frame = Coord 0 Domain Type = Fluid Fluids List = Air Ideal Gas Location = tunnel Assembly BOUNDARY: discback Side 2 Boundary Type = INTERFACE Location = F521.452,F519.452 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: frontdisc Side 1 Boundary Type = INTERFACE Location = F516.452,F518.452 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: inlet Boundary Type = INLET Location = inlet BOUNDARY CONDITIONS: FLOW REGIME: Option = Subsonic END MASS AND MOMENTUM: Normal Speed = 10 [m s^-1] Option = Normal Speed END TURBULENCE: Option = High Intensity and Eddy Viscosity Ratio END END END BOUNDARY: outerdisc Side 2 Boundary Type = INTERFACE Location = F515.452,F517.452 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: outlet Boundary Type = OUTLET Location = outlet BOUNDARY CONDITIONS: FLOW REGIME: Option = Subsonic END MASS AND MOMENTUM: Option = Average Static Pressure Relative Pressure = 0 [Pa] END PRESSURE AVERAGING: Option = Average Over Whole Outlet END END END BOUNDARY: tunnel Default Boundary Type = WALL Location = \ F522.452,F524.452,F525.452,F526.452,F527.452,F528. 452,F529.452,F530.4\ 52,F531.452,F532.452,F541.452,F551.452 BOUNDARY CONDITIONS: WALL INFLUENCE ON FLOW: Option = No Slip END END END BOUNDARY: wall Boundary Type = WALL Location = wall BOUNDARY CONDITIONS: WALL INFLUENCE ON FLOW: Option = No Slip END END END DOMAIN MODELS: BUOYANCY MODEL: Option = Non Buoyant END DOMAIN MOTION: Option = Stationary END MESH DEFORMATION: Option = None END REFERENCE PRESSURE: Reference Pressure = 1 [atm] END END FLUID MODELS: COMBUSTION MODEL: Option = None END HEAT TRANSFER MODEL: Fluid Temperature = 283.15 [K] Option = Isothermal END THERMAL RADIATION MODEL: Option = None END TURBULENCE MODEL: Option = SST END TURBULENT WALL FUNCTIONS: Option = Automatic END END INITIALISATION: Coord Frame = Coord 0 Option = Automatic INITIAL CONDITIONS: Velocity Type = Cartesian CARTESIAN VELOCITY COMPONENTS: Option = Automatic with Value U = 10 [m s^-1] V = 0 [m s^-1] W = 0 [m s^-1] END K: Fractional Intensity = 0.05 Option = Automatic with Value END OMEGA: Option = Automatic END STATIC PRESSURE: Option = Automatic with Value Relative Pressure = 101325 [Pa] END END END END DOMAIN INTERFACE: discback Boundary List1 = discback Side 1 Boundary List2 = discback Side 2 Interface Type = Fluid Fluid INTERFACE MODELS: Option = General Connection FRAME CHANGE: Option = Transient Rotor Stator END PITCH CHANGE: Option = None END END MESH CONNECTION: Option = GGI END END DOMAIN INTERFACE: frontdisc Boundary List1 = frontdisc Side 1 Boundary List2 = frontdisc Side 2 Interface Type = Fluid Fluid INTERFACE MODELS: Option = General Connection FRAME CHANGE: Option = Transient Rotor Stator END PITCH CHANGE: Option = None END END MESH CONNECTION: Option = GGI END END DOMAIN INTERFACE: outerdisc Boundary List1 = outerdisc Side 1 Boundary List2 = outerdisc Side 2 Interface Type = Fluid Fluid INTERFACE MODELS: Option = General Connection FRAME CHANGE: Option = Transient Rotor Stator END PITCH CHANGE: Option = None END END MESH CONNECTION: Option = GGI END END DOMAIN INTERFACE: per1 Boundary List1 = per1 Side 1 Boundary List2 = per1 Side 2 Interface Type = Fluid Fluid INTERFACE MODELS: Option = General Connection FRAME CHANGE: Option = None END PITCH CHANGE: Option = None END END MESH CONNECTION: Option = Automatic END END DOMAIN INTERFACE: per2 Boundary List1 = per2 Side 1 Boundary List2 = per2 Side 2 Interface Type = Fluid Fluid INTERFACE MODELS: Option = General Connection FRAME CHANGE: Option = None END PITCH CHANGE: Option = None END END MESH CONNECTION: Option = GGI END END OUTPUT CONTROL: RESULTS: File Compression Level = Default Option = Standard END TRANSIENT RESULTS: Transient Results 1 File Compression Level = Default Option = Standard Output Boundary Flows = All OUTPUT FREQUENCY: Option = Timestep Interval Timestep Interval = 101 END END END SOLVER CONTROL: ADVECTION SCHEME: Option = High Resolution END CONVERGENCE CONTROL: Maximum Number of Coefficient Loops = 10 Minimum Number of Coefficient Loops = 3 Timescale Control = Coefficient Loops END CONVERGENCE CRITERIA: Conservation Target = 0.01 Residual Target = 1.E-4 Residual Type = RMS END TRANSIENT SCHEME: Option = Second Order Backward Euler TIMESTEP INITIALISATION: Option = Automatic END END END END COMMAND FILE: Results Version = 11.0 Version = 11.0 END EXECUTION CONTROL: INTERPOLATOR STEP CONTROL: Runtime Priority = Standard EXECUTABLE SELECTION: Double Precision = Off END MEMORY CONTROL: Memory Allocation Factor = 1.0 END END PARALLEL HOST LIBRARY: HOST DEFINITION: sivaram Installation Root = C:\Program Files\Ansys Inc\v%v\CFX Host Architecture String = amd_opteron.sse2_winnt5.1 END END PARTITIONER STEP CONTROL: Multidomain Option = Independent Partitioning Runtime Priority = Standard EXECUTABLE SELECTION: Use Large Problem Partitioner = Off END MEMORY CONTROL: Memory Allocation Factor = 1.0 END PARTITIONING TYPE: MeTiS Type = k-way Option = MeTiS Partition Size Rule = Automatic END END RUN DEFINITION: Definition File = D:/tutorial/CFX/wind_3blade3_002_001.def Initial Values File = D:/tutorial/CFX/wind_3blade2_002_001.res Interpolate Initial Values = Off Run Mode = Full END SOLVER STEP CONTROL: Runtime Priority = Standard EXECUTABLE SELECTION: Double Precision = Off END MEMORY CONTROL: Memory Allocation Factor = 1.0 END PARALLEL ENVIRONMENT: Number of Processes = 1 Start Method = Serial END END END |
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hi sir, can u send me the boundary conditions which u applied in cfx so i can try the solution in cfx too. |
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Although the original thread looks outdated, but when I read your answer and Suraj's reasons, I became confused that Suraj is right somewhat, and you 100%. Because the blades will be equally loaded in axial steady case ,but the points that Suraj says also make sense. Do you have any solution for this contradiction or you just say"REGARDLESS" what the real/theoretical results are... it will be "n" times the results of single blade. Then, if you confirm the previous answer what is the cause of this HUGE difference between this two...? and PLZ remember than Suraj's points are in contradiction with energy conservation law... TNX |
My point was simply that for even blade loading, each blade supplies 1/n of the torque. I said nothing about how much extra torque you get by adding more blades. That is a different question so don't get confused.
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5 MW offshore wind turbine
1 Attachment(s)
Hi for all
I am trying to simulate 5 MW offshore wind turbine (aerodynamics study only) using CFX to validate my results which were coming from another solver, under these conditions · Full scale of 5 MW offshore wind turbine dimensions · transient analysis · Inlet velocity = 9 m/sec · 3 blade rotor + hub (rotating domain) with angular velocity =1.08 rad/sec · Nacelle + tower (stationary domain) · Then, three interfaces have been defined between the stationary domain and the rotating domain due to changes in reference frames. In order to rotate the rotor in ANSYS. · I create appropriate and suitable meshes for all the parts in ICEM and CFX is specifying domains, boundary conditions, type of analysis, interfaces, etc. But I always I find this error First side of interface | | Domain Interface 1 | | seems to contain a vertex at R=0 (Rmin/Rrange < GGI ETA TOLERANCE).| | This is not supported with | | PITCH CHANGE/Option = Automatic | | Please use | | PITCH CHANGE/Option = None | | instead. | +--------------------------------------------------------------------+ +--------------------------------------------------------------------+ | ********* WARNING ********* | | Coordinate transformation of interface | | Domain Interface 2 | | into a radial interface resulted in some faces with a very small | | axial extent. There are two possible reasons for this: | | 1. The interface contains axial faces (normal to the axis). | | If this is the case, please split the interface into two parts, | | so that the purely axial sections could be transformed | | properly. The transformation type (axial or radial) is chosen | | automatically based on the largest interface extent. | | 2. This message may be generated because of a tolerancing issue | | when the mesh resolution in the axial direction is very | | small (e.g. at the hub or shroud). If this is the case, you | | may ignore this message. | +--------------------------------------------------------------------+ +--------------------------------------------------------------------+ | ERROR #001100279 has occurred in subroutine ErrAction. | | Message: | | ****** FATAL ERROR ****** The orthographic view transformation fa- | | iled on domain interface "Domain Interface 2". Failure may be du- | | e to r=0 included in transformed cylindrical coordinates of an in- | | terface with rotational relative motion. Another reason could be | | that the interface contains faces that are parallel and others t- | | hat are perpendicular to the rotation axis. | +--------------------------------------------------------------------+ </SPAN> When I selected (PITCH CHANGE/Option = Automatic ) which I thought is correct chose but the above error will appear And when I selected (PITCH CHANGE/Option = None) the run continue and complete, everything is ok, but the values of torque is negative ???? :mad: thanks |
It looks like you are modelling the whole thing so you are correct to use pitch change=none. As for the negative torque, have you checked the vector direction of the torque?
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hi
do you means that, by using the right hand rule can i find the torque direction thanks:) |
Just had a look at the torque function in the CFX reference manual. If you use the torque_x, torque_y, torque_z functions it returns the torque about the X, Y and Z coordinate axis respectively (and yes you can use the RH rule to get the direction). But the axis specification is optional and it is not clear what axis it uses if you just use the torque function with no axis defined.
Does anybody know what axis the torque function uses if no axis is defined? To get around this I would just use the torque_x/y/z functions so you know exactly what axis it is using. |
thanks for your answer
but I calculate the torque of the rotor on the rotation axis torque_x()@BLADE +torque_x()@BLADE1 +torque_x()@BLADE2 which appear for me negative despite of the rotation of the blades counter-clockwise |
To get the correct result in a rotating machine simulation, you need to not only get the numerics correct, but you also need to get the operating point correct. This means that the rotation speed might be a little faster or slower.
So negative torque means the rotation speed is slower - assuming your simulation is accurate. |
:) can I give a negative value for the rotation speed
for the rotational domain and I checked some of paper that use the same rotational speed with the same dimension of my wind turbine and got a positive value of torque |
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thanks again you are so helpful
and I will try to do simulation with -1.08 rad/s |
3 d simulation of helicel turbine in cfx
hi,
i m trying to simulate a helical turbine but i only know the inlet velocity.so how to perform transient analysis? of it.Do i need to take two domain one stationary and one rotating?plz suggest something |
You will need to know a pressure somewhere to set the pressure level.
Look at the CFX tutorials for how to run simulations. And in future, if you have a new question start a new thread rather than hijacking an old thread. |
inquiry about wind power using ansys fluent 15
hello,
i am using fluent 15, after i draw the horizontal turbine using solidworks, i made a run of fluent with omega and input wind speed, using k-omega sst model, the resultant torque multiplied with the omega to get the power. the question is: the calculated power using ansys can be compared with the net power of commercial turbine directly, " or should be multiplied to rotor efficiency first before comparing with net power of commercial turbine? |
The power at the rotor shaft (torque x omega) should match the torque at the rotor shaft of the turbine.
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but i am not comparing with torque at the rotor shaft of the turbine,,,
i am comparing power from ansys ( omega x torque) with the net producing power from the generator where the commercial turbine connected to. so i think that a parameter of efficiency of rotor and generator and inverter should be included. |
You can only compare the CFD computed rotor power to the rotor power of the real machine. If it's not possible to find the real rotor's power, you may need to find it by either experiment (if it's possible) or by asking the manufacturer.
If you know the efficiency of the generator, etc, you should try to use it to make an approximation of the net aerodynamic rotor power. |
you are correct,,,i am trying to compare the ansys power (torque x omega) with the generator power ,,,,but i think the rotor efficicency and inverter efficiency and generator efficiency should be included,,
am i right? |
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