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-   -   3D wind turbine modelling/boundary condition defn in rotation (http://www.cfd-online.com/Forums/fluent/71188-3d-wind-turbine-modelling-boundary-condition-defn-rotation.html)

bakay December 18, 2009 10:57

3D wind turbine modelling/boundary condition defn in rotation
 
I have some problems defining the boundary conditions in freestream case and wind tunnel case simulations. Since in freestream case, I need to give rotation to freestream and blades as well.

If someone has experience modelling wind turbine, please let me know!

thanks,
Busra

anshulmittal1912 December 22, 2009 22:39

I have done wind turbine modeling. Could you be more specific with your question.

Anshul

bakay January 19, 2010 07:30

Quote:

Originally Posted by anshulmittal1912 (Post 240785)
I have done wind turbine modeling. Could you be more specific with your question.

Anshul

I am sorry for replying you late. I was busy with sth else..

I have some doubts by defining the boundary condition of the blade in rotation for freestream case (whole fluid domain and blades are rotating). Based on the fluent guide, if I let the blades wall in stationary condition then fluent automatically gives a rotation to the walls relative to the adjacent cell zones (fluid). I assumed it should give the same results when I run it by giving 0 rotational velocity (relative to the cell zones) to the walls. But it didnt give the same result!

when I check the moment coefficient, it is less than the one that I calculated in BEM. I also check the flow close to tip (90% of the span), there is separation which is surprising at that location. this is because a high inflow angle. I do not know why the inflow angle is so high!

if you have any idea, I am glad to hear..

thanks,
Busra

saini.yashwant April 20, 2010 04:52

wind turbine
 
Quote:

Originally Posted by anshulmittal1912 (Post 240785)
I have done wind turbine modeling. Could you be more specific with your question.

Anshul

sir,

i have done modeling and meshing in gambit and i am having some problem with fluent analysis. regarding boundary condition and how to calculate the axial induction factor , power and power coefficient directly from fluent

anshulmittal1912 April 20, 2010 16:30

Hello,

Could you be more specific as to what problem you are facing?
Give some details about your simulation case.

saini.yashwant April 21, 2010 00:07

Quote:

Originally Posted by anshulmittal1912 (Post 255519)
Hello,

Could you be more specific as to what problem you are facing?
Give some details about your simulation case.

sir,
i hav done the modeling in gambit and meshing for wind turbine rotor. i hav meshed full rotor with outside domain with 1.5D dia. how to give the rotation to the axial wind turbine rotor. should i use MRF or directly i can give rotation to the Rotor blade by specifying it as a wall in gambit. so please tel me how to give rotation to the rotor blade. and how to find out the power output directly from fluent.

saini.yashwant April 22, 2010 22:41

wind turbine
 
Quote:

Originally Posted by anshulmittal1912 (Post 255519)
Hello,

Could you be more specific as to what problem you are facing?
Give some details about your simulation case.

sir i am student of M.tech at NIT surat. i am doing numerical simulation of wind turbine by fluent. so i am facing some problems with defining the boundary conditions. so wl u please help me regarding boundary conditions.sir i have modeled wind turbine in gambit and meshed it with two domain interior domain with .5d same as wind radius. and another one is off bigger domain of 4d in diameter. and 3d in front and 5d in back. i have defined the interface in between the surfaces of interior and outer domain. by giving the condition of rotor stationary and the near by domain air is rotating i am getting the axial velocity at the rotor plane more than inlet velocity. is this correct or not. and please help me out how to calculate the power output and coefficient of power.
thanks
--

anshulmittal1912 April 23, 2010 00:13

Dear Yashwant,

I understand the geometry that you have created.
Are you using the MRF?
I think this problem requires the use of MRF.

Anshul

saini.yashwant April 23, 2010 00:19

sir i am usinf mrf but how weather its conditions are correct or not please tel me or if u have gmail id then i can mail u their my summery of fluent and gambit jounral file so i can get some direction

mu ke September 14, 2011 05:32

Hi Anshmital1912!
I am also validating results for NREL Phase VI turbine blade. I am using FLUENT s/w. I have modelled the Fluid domain as moving reference frame (with radian per second as the rotational speed) and in the walls (blade walls) I selected moving wall with zero velocity. The velocity inlet was applied at the far-field cylinder domain and the top surface of the cylinder. The outflow was specified as outlet of the far-field cylinder. I check the moment in z-axis but it is not comparable with experimental results (experimental results are almost double).

Conditions
SIMPLE solver
cases: 1st order (pressure and momentum) laminar first then
2nd order laminar and then
2nd order transition SST
Velocities 7,10,15,20 and 25m/s


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