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!

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

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

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

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

please tell me, how to calculate torque by fluen

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

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

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/

[suraj123khalate]

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

[ghorrocks]

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

[suraj123khalate]

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

[ghorrocks]

No, that is not what I am saying at all. Please read my original post again carefully.

Glenn Horrocks

[suraj123khalate]

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

[zelito]

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.

[zelito]

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

[holyo]

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 don´t know how introduce it.

Thank you.

[ghorrocks]

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

[rogbrito]

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.

[sivarama1]

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