Torque of wind turbine simulation

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June 8, 2010, 18:27
Torque of wind turbine simulation
#1
Member

tom
Join Date: Feb 2010
Posts: 46
Rep Power: 8
Hi All,
I am a newbie of CFD simulation, now I am doing a wind turbine simulation.The tested wind turbine is 20 kw, untwisted rotor sized at a diameter of 10.1m and constant chord length is 0.458m, wind speed is 10m/s, during this situation, the roatational speed is assumed as 72 rpm.Viscous model is standard k-e, MRF and sliding mesh both were used in my model.
here are the velocity and pressure contours by using MRF. The pics looks normal, but the moment is too big when I export the report.
this is the pressure moment
(-70.524025 -54.304947 18263.371)
this is the viscous moment
(-0.73487449 3.8853738 59.417488)
this is the total moment
(-71.258899 -50.419573 18322.789)
because the rotational axis is z-axis, so someone tell me I should only focus on the moment on z-direction which is 18322.789. is it correct? if it is, by using this value, the output power is 138.15 kw. this is unbelievable, because the actual wind turbine only has 20 kw output power. does somebody has the same problem with me. really hope someone can help me get through it!!

Han
Attached Images
 1.jpg (13.1 KB, 142 views) 2.jpg (16.6 KB, 135 views) 3.jpg (36.3 KB, 149 views)

 June 9, 2010, 17:52 #2 New Member   Join Date: Jan 2010 Posts: 28 Rep Power: 8 It looks like we have the same problem....hope someone will explain what's wrong. I suggest u to visit Setting condition on a VAWT There in last post i write i said how i have done the simulation. Maybe we have some error in common.

June 10, 2010, 08:09
#3
Member

tom
Join Date: Feb 2010
Posts: 46
Rep Power: 8
Quote:
 Originally Posted by esp-m1000 It looks like we have the same problem....hope someone will explain what's wrong. I suggest u to visit Setting condition on a VAWT There in last post i write i said how i have done the simulation. Maybe we have some error in common.
Hi esp-m1000,
Thank you for your reply, maybe we can work together to find out what kind of issue will cause such a big error. are you using MRF or sliding mesh to simulate you model? I try both two ways and result make me disappointed. by the way, how can you calculate the moment in Fluent, did you export the moment from report?
Han

 June 10, 2010, 09:06 #4 New Member   Join Date: Jan 2010 Posts: 28 Rep Power: 8 I'm using sliding mesh, and to calculate the moment i export the moment from report. I monitor the Cm of the turbine in: solve -> monitors -> force: options: print, plot and write wall zones: turbine coefficient: moment moment center (0,0,0) I don't know what's wrong.....

 March 26, 2014, 00:46 #5 New Member   Aalisha Join Date: Jan 2014 Posts: 18 Rep Power: 4 Hello Caohan and esp-m1000, have you find the error? I am also doing something similar on vertical axis tidal turbine. and can you please help me to find the torque using Cm..

 August 7, 2014, 10:01 #6 New Member   amin veysi Join Date: May 2013 Posts: 5 Rep Power: 5 hi you must change the reference value, in this case you must change area from 1 to sweep area, length from 1 to radius of blade and velocity from one to hub velocity

 August 8, 2014, 09:48 #7 New Member   UPmero Join Date: Aug 2014 Posts: 3 Rep Power: 4 hi all, I am also facing same kind of problem. Even I changed the reference value of the area 1m^2 to swept area and length was also changed from 1m to radius of the rotor. By the way I do not understand what do you mean by hub velocity @ amin_veysi.

 August 8, 2014, 10:09 #8 New Member   UPmero Join Date: Aug 2014 Posts: 3 Rep Power: 4 @ amin_veysi how many cell zone will appear if we use sliding mesh condition? In our case it is 2. Is it correct?

 August 11, 2014, 23:01 #9 New Member   Aalisha Join Date: Jan 2014 Posts: 18 Rep Power: 4 Hey amin, Actually even after changing the reference values, I was not sure about the value power of co-efficient by using co-efficient of moment. However, now I am using Cp= Cm X Tip speed ratio.

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