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-   -   Turbine moving blades - impossible? (http://www.cfd-online.com/Forums/fluent/96200-turbine-moving-blades-impossible.html)

JSoares January 16, 2012 08:10

Turbine moving blades - impossible?
 
Hello CFD users,

In first place thanks in advance for the time spent reading this post.

Im trying to simulate an hydraulic turbine, wich have some specific details. In the presente moment, ive achived the steps from sketch to simulation, and had no problem with the movement of rotation.

But as i said, there are some specific details, like the blades should move with flow of water. The connection between the blades and the rotor is an rotation axis, wich is simple to draw in solidworks but hard to simulate in fluent.

Sugestions or even doubts would be appreciated?

Thank you.

P.S. : I posted an image with the purpose of facilitating understanding

http://imageshack.us/photo/my-images/402/imagemgyq.jpg/

JSoares January 18, 2012 13:27

Im just wondering if i put any silly question?!? If so, explain to me please.
Ive been working with fluent almost a year in diferent areas, but now ive a problem with moving parts.

I really dont know how to do this, if anyone could help, i will be thankfull.
Yet i post another image so you can see the turbine, and understand better my problem. As you can see the blades are connected to the rotor with a pin, and they move with flow.
I understand when you simulate a turbine with fluent we have to indicate de rotor rotational speed, yet if we want that some part to move with the flow, how to do this?

http://imageshack.us/photo/my-images/703/turbinab.jpg/

Regards,

Joao Soares

Far January 18, 2012 14:11

All blades move with flow, but we model them in steady state by assuming the flow in rotational reference frame and thereby avoiding many complications. Please elaborate your problem more and why think your problem cant be solved with the standard methods? and why you need the moving mesh algorithm?

JSoares January 20, 2012 08:20

Thanks for the reply.

Assume the simple case of all the blades are opened, and fixed to the rotor, that is not possible for the same motion. In this case the use of a frame rotation is possible and desirable. However, I have no problem with this simulation, but I also know how to solve them.

The real problem is that the blades have a relative movement in relation to the rotor, ie, they open and close with the flow. As can be seen in the figure, the upper blades are opened and closed from the bottom. This movement of opening and closing should be done only with the flow, ie if it focuses on the blade (upper) it opens and when it is blocked by water (the bottom) it closes. The fact that they open or close will be the subject of analysis, but this is not my problem. The problem is finding a way to enter the zone of connection between the blade and rotor, articulated a link in order to allow them to move about.

So my question is, is it possible to accomplish this using fluent?

Regards,

John Smith


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