Turbine moving blades - impossible?

JSoares · January 16, 2012, 08:10

Hello CFD user´s,

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

I´m trying to simulate an hydraulic turbine, wich have some specific details. In the presente moment, i´ve 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

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

I really don´t 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

January 16, 2012, 08:10	Turbine moving blades - impossible?	#1
JSoares New Member Join Date: Feb 2011 Posts: 16 Rep Power: 15	Hello CFD user´s, In first place thanks in advance for the time spent reading this post. I´m trying to simulate an hydraulic turbine, wich have some specific details. In the presente moment, i´ve 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/ Last edited by wyldckat; September 3, 2015 at 18:45. Reason: disabled embedded images

January 18, 2012, 13:27		#2
JSoares New Member Join Date: Feb 2011 Posts: 16 Rep Power: 15	I´m just wondering if i put any silly question?!? If so, explain to me please. I´ve been working with fluent almost a year in diferent areas, but now i´ve a problem with moving parts. I really don´t 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 Last edited by wyldckat; September 3, 2015 at 18:45. Reason: disabled embedded images

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January 18, 2012, 14:11		#3
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	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?

January 20, 2012, 08:20		#4
JSoares New Member Join Date: Feb 2011 Posts: 16 Rep Power: 15	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