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-   -   Rotating A turbine Blade (http://www.cfd-online.com/Forums/cfx/91954-rotating-turbine-blade.html)

charlestchan August 28, 2011 04:36

Rotating A turbine Blade
 
I have manage to simulate a vortex in a cyclinder tank, however, i have no idea how should i make the blade rotate due to the vortex impact. I attached a few picture to make my explanation clearer.

http://img200.imageshack.us/img200/5...simulation.jpg

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http://img143.imageshack.us/img143/5429/example2up.jpg

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I still can't get the blade to turn from the flow of water, anyone can help me?

ghorrocks August 28, 2011 06:37

If you are looking for the steady state solution to this the easiest way is to guess a rotation speed and run the model. Then guess another speed and get another result. You will start generating points on the torque versus speed characteristic for your device, and once you know the curve well enough you can interpolate to zero net torque which is you operating point.

This approach is much easier than trying to get the simulation to converge on a rotor speed.

charlestchan August 28, 2011 06:44

thanks for your help

charlestchan August 28, 2011 06:47

This is how i do it. I draw the tank and blade separately in catia, then i import them into ansys. After that, i mesh both of them together. I set Fluid as domain 1, where i can set the inlet, outlet and wall. Then i set The blade as immersed solid domain 2, and i put it rotating as certain rpm. Am i on track or am i wrong?

ghorrocks August 28, 2011 07:05

Close but no. Do not use the immersed solid approach. Use a rotating frame of reference approach. See the RFR examples in the CFX tutorials for tips on how to set it up.

charlestchan August 28, 2011 07:11

I'll check out on that. Thanks ghorrocks.. can i pm u when i'm stuck again?

ghorrocks August 28, 2011 07:18

Please put general questions on the forum. This is so other people can have their say if they want, and so people can see the answers if they want.

Keep PM for messages which are actually private.

charlestchan August 28, 2011 08:51

My university doesn't want to share the tutorial files for ansys cfx, but i heard that i can learn about rotating frame reference from the vertical turbine tutorial, do u know where i can get it?

charlestchan August 28, 2011 14:22

May i ask u again, whether the fluid should be rotating? or the blade? i mean when i'm setting up Moving reference frame.

charlestchan August 28, 2011 16:42

Fluent is not user friendly as CFX.. i have trouble identifying the parts as it is not highlighted in FLUENT

ghorrocks August 28, 2011 18:48

The CFX tutorials are all installed with CFX. From the launcher, help/CFX/Tutorials.

charlestchan August 28, 2011 23:11

thanks man.. i'll try again

charlestchan August 31, 2011 03:15

Firstly, i have no idea how to set a rotating frame, second, i don't know where to see the torque vs speed graph, lastly, i don't know how to use CEL. Anyone can provide screenshot to guide me a little? please?

charlestchan August 31, 2011 03:17

The turbine is attached to a generator, so , in order to measure the efficiency of the turbine from Ansys, it is possible to assume that the turbine is rotating as simulated right? Or will there be any other effects in real life set up?

ghorrocks August 31, 2011 06:51

As I said earlier look at the rotating frame of reference tutorial example. Also read the turbomachinery best practices guide.

charlestchan September 8, 2011 05:07

Do i need to set an opening boundary? I've set inlet , outlet and wall.

ghorrocks September 8, 2011 07:47

Inlet, outlet and wall should be OK, but I do not know the detail of what you are doing so cannot be definite about it.

charlestchan September 10, 2011 14:39

How do i animate the solid domain rotation? i only can animate streamline which is insufficient.

ghorrocks September 12, 2011 20:05

If you did this model as transient rotor/stator then making an animation with a rotating rotor is easy. If you did this model as frozen rotor then it will not be possible as your simulation is just a snapshot at that rotation position.

charlestchan September 13, 2011 04:59

I've already set the analysis type to transient.. but i still don't see how the immersed solid going to rotate.. any idea?


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