output power of wind turbine

niloogh · May 16, 2013, 11:23

hi
I had simulated a wind turbine using fluent and I want to calculate the output power(mechanical power) of it in different wind speeds .
I don't know how to evaluate the output power.
would you plz help me??

blackmask · May 16, 2013, 20:22

Power = Torque*omega.
Assume the axis of the rotor is in the z-direction, and you set the origin at the axis of your rotor, then torque is the z-moment. The omega is angular velocity you specified for the rotor.

niloogh · May 17, 2013, 11:03

tnx a lot dear
it was really useful for me.
i have another problem which my moment amounts are negative!!!!
my flow comes from y- to y+
i had set my velocity inlet -11
and my rotation direction is +y

would you plz help me???

niloogh · May 24, 2013, 15:34

Quote:

Originally Posted by blackmask

Power = Torque*omega.
Assume the axis of the rotor is in the z-direction, and you set the origin at the axis of your rotor, then torque is the z-moment. The omega is angular velocity you specified for the rotor.

hi dear
i have got smaller amount for my simulation using your formula mentioned above.
all of them are 100 order smaller:
46kw in stead of 4600kw

would you plz help me to find the reason.

s.q · May 28, 2013, 05:26

Quote:

Originally Posted by blackmask

Power = Torque*omega.
Assume the axis of the rotor is in the z-direction, and you set the origin at the axis of your rotor, then torque is the z-moment. The omega is angular velocity you specified for the rotor.

hi blackmask
i,m using the way that you mentioned in this forum but my results are about 10 times bigger than the exact amounts.

i really need help

.would you plz guide me???

blackmask · May 28, 2013, 07:31

Then the power coefficient should exceed the Betz limit. Make sure that the angular velocity is expressed in rad/s rather than RPM.

s.q · May 28, 2013, 08:17

Quote:

Originally Posted by blackmask

Then the power coefficient should exceed the Betz limit. Make sure that the angular velocity is expressed in rad/s rather than RPM.

my angular velocity is in rpm and i set it in units panel too.

where can i change the cp in fluent????
or how can i totally reduce cp ??????

blackmask · May 28, 2013, 08:34

OK. Tell me your RPM, aerodynamic torque and the rated power of the wind turbine. If your result is reasonable then you might calculate your power with the wrong unit for ten is closed to 60/(2 pi).

niloogh · May 28, 2013, 08:38

Quote:

Originally Posted by blackmask

OK. Tell me your RPM, aerodynamic torque and the rated power of the wind turbine. If your result is reasonable then you might calculate your power with the wrong unit for ten is closed to 60/(2 pi).

my rated power : 5 MW
torque in fluent: 51084019 nm
ang velocity:12 rpm

s.q · May 28, 2013, 08:43

Quote:

Originally Posted by blackmask

OK. Tell me your RPM, aerodynamic torque and the rated power of the wind turbine. If your result is reasonable then you might calculate your power with the wrong unit for ten is closed to 60/(2 pi).

my rated power : 5 MW
torque in fluent: 51084019 nm
ang velocity:12 rpm

blackmask · May 28, 2013, 08:45

Are you sure? The aerodynamic torque is 5.1E7 N.m.
T=5.1E7
omega = 12*2*pi/60 = 1.2566
P = T*omega = 64.2 MW
What is your rotor diameter, rated velocity and the velocity your used in your computation?

s.q · May 28, 2013, 08:50

Quote:

Originally Posted by blackmask

Are you sure? The aerodynamic torque is 5.1E7 N.m.
T=5.1E7
omega = 12*2*pi/60 = 1.2566
P = T*omega = 64.2 MW
What is your rotor diameter, rated velocity and the velocity your used in your computation?

i have this torque from:report-forces-moment-moment center(0,0,0)
rotor diameter:63m
rated wind velocity:11m/s
rated ang velocity and my rotational velocity :12rpm

s.q · May 28, 2013, 08:51

Quote:

Originally Posted by blackmask

Are you sure? The aerodynamic torque is 5.1E7 N.m.
T=5.1E7
omega = 12*2*pi/60 = 1.2566
P = T*omega = 64.2 MW
What is your rotor diameter, rated velocity and the velocity your used in your computation?

i have this torque from:report-forces-moment-moment center(0,0,0) total moment in y direction
rotor diameter:63m
rated wind velocity:11m/s
rated and velocity and my rotational velocity :12rpm

blackmask · May 28, 2013, 08:53

What is the location of your rotor shaft?

s.q · May 28, 2013, 08:56

Quote:

Originally Posted by blackmask

What is the location of your rotor shaft?

the center of hub is located at (0,0,0)
the blades rotate around y axis

i imported geometry from gambit

s.q · May 28, 2013, 09:17

Quote:

Originally Posted by blackmask

What is the location of your rotor shaft?

do you have any idea about this problem?
any suggestion

blackmask · May 28, 2013, 09:27

Maybe your computation does not converge. Please check your converge history. If possible please post a contour plot of axial velocity on a slice at the hub height.

s.q · May 28, 2013, 09:42

Quote:

Originally Posted by blackmask

Maybe your computation does not converge. Please check your converge history. If possible please post a contour plot of axial velocity on a slice at the hub height.

this are photos of my residuals and velocity contour
in addition mass flow rate difference between inlet and outlet is 250 kg/s when the total inlet mass flow is 693639.75 kg/s

axial velocity contour in y=0 plan

blackmask · May 28, 2013, 09:47

Please monitor the force and moment of your rotor and continue calculation until the force and moment converge.

s.q · May 28, 2013, 13:58

Quote:

Originally Posted by blackmask

Please monitor the force and moment of your rotor and continue calculation until the force and moment converge.

hi blackmask
i had done what you told.

please take a look at this photos and check if my solution is converged or not.
in this situation the torque is 44944300

May 16, 2013, 11:23	output power of wind turbine	#1
niloogh Member Join Date: Mar 2013 Posts: 48 Rep Power: 13	hi I had simulated a wind turbine using fluent and I want to calculate the output power(mechanical power) of it in different wind speeds . I don't know how to evaluate the output power. would you plz help me??

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May 16, 2013, 20:22		#2
blackmask Senior Member Join Date: Aug 2011 Posts: 421 Blog Entries: 1 Rep Power: 21	Power = Torque*omega. Assume the axis of the rotor is in the z-direction, and you set the origin at the axis of your rotor, then torque is the z-moment. The omega is angular velocity you specified for the rotor.

May 17, 2013, 11:03		#3
niloogh Member Join Date: Mar 2013 Posts: 48 Rep Power: 13	tnx a lot dear it was really useful for me. i have another problem which my moment amounts are negative!!!! my flow comes from y- to y+ i had set my velocity inlet -11 and my rotation direction is +y would you plz help me???

May 28, 2013, 07:31		#6
blackmask Senior Member Join Date: Aug 2011 Posts: 421 Blog Entries: 1 Rep Power: 21	Then the power coefficient should exceed the Betz limit. Make sure that the angular velocity is expressed in rad/s rather than RPM.

May 28, 2013, 08:34		#8
blackmask Senior Member Join Date: Aug 2011 Posts: 421 Blog Entries: 1 Rep Power: 21	OK. Tell me your RPM, aerodynamic torque and the rated power of the wind turbine. If your result is reasonable then you might calculate your power with the wrong unit for ten is closed to 60/(2 pi).

May 28, 2013, 08:45		#11
blackmask Senior Member Join Date: Aug 2011 Posts: 421 Blog Entries: 1 Rep Power: 21	Are you sure? The aerodynamic torque is 5.1E7 N.m. T=5.1E7 omega = 122pi/60 = 1.2566 P = T*omega = 64.2 MW What is your rotor diameter, rated velocity and the velocity your used in your computation?

May 28, 2013, 08:53		#14
blackmask Senior Member Join Date: Aug 2011 Posts: 421 Blog Entries: 1 Rep Power: 21	What is the location of your rotor shaft?

May 28, 2013, 09:27		#17
blackmask Senior Member Join Date: Aug 2011 Posts: 421 Blog Entries: 1 Rep Power: 21	Maybe your computation does not converge. Please check your converge history. If possible please post a contour plot of axial velocity on a slice at the hub height.

May 28, 2013, 09:47		#19
blackmask Senior Member Join Date: Aug 2011 Posts: 421 Blog Entries: 1 Rep Power: 21	Please monitor the force and moment of your rotor and continue calculation until the force and moment converge.