Post: How to define a moving plane with bounds

Peter1200 · March 3, 2016, 06:01

Hey,

I`d like to calculate the mass flow through a gap between the immersed solid and the housing.
Therefore, I need to define a location, means a plane to use in the expression. I know how to do that by using the Plane Bounds with the rectangular type.
However, fixed values for the X/Y Size of this rectangle is not approrpiate since the gap varies a little bit if the immersed solid is moving. That would distort the results of this analysis.

Thus, I would like to ask firstly: how I can define a plane that is exactly between the immersed solid and the end of the fluid mesh in in the YZ view.

Secondly: How can I determine such a plane that is moving with the rotary piston motion and represents the actual gap between the immersed solid at that point and the housing (end of the mesh).

Thank you very much for your hints!

Regards,

Peter

ghorrocks · March 3, 2016, 17:15

This sounds tricky. Does this leakage flow then cause some backflow in the inlet or outlet? It would be easier to measure this backflow.

Peter1200 · March 4, 2016, 04:59

Hi ghorrocks,
yes, it causes backflow in the inlets and outlets. However, one rotor works in two pump halves. If there were no gaps between the rotor and the pump housing, each pump half could be seen as a single, independent pump. But reality is more tricky, there are radial and axial gaps and fluid flows through those gaps from one pump half into the other, according to the actual pressure gradients. And this is what I need to investigate...

ghorrocks · March 4, 2016, 05:47

You could define the plane as a function of the body position using expressions. I can't think of any other way to do it.

March 3, 2016, 06:01	Post: How to define a moving plane with bounds	#1
Peter1200 New Member Join Date: Mar 2016 Posts: 2 Rep Power: 0	Hey, I`d like to calculate the mass flow through a gap between the immersed solid and the housing. Therefore, I need to define a location, means a plane to use in the expression. I know how to do that by using the Plane Bounds with the rectangular type. However, fixed values for the X/Y Size of this rectangle is not approrpiate since the gap varies a little bit if the immersed solid is moving. That would distort the results of this analysis. Thus, I would like to ask firstly: how I can define a plane that is exactly between the immersed solid and the end of the fluid mesh in in the YZ view. Secondly: How can I determine such a plane that is moving with the rotary piston motion and represents the actual gap between the immersed solid at that point and the housing (end of the mesh). Thank you very much for your hints! Regards, Peter

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March 3, 2016, 17:15		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	This sounds tricky. Does this leakage flow then cause some backflow in the inlet or outlet? It would be easier to measure this backflow.

March 4, 2016, 04:59		#3
Peter1200 New Member Join Date: Mar 2016 Posts: 2 Rep Power: 0	Hi ghorrocks, yes, it causes backflow in the inlets and outlets. However, one rotor works in two pump halves. If there were no gaps between the rotor and the pump housing, each pump half could be seen as a single, independent pump. But reality is more tricky, there are radial and axial gaps and fluid flows through those gaps from one pump half into the other, according to the actual pressure gradients. And this is what I need to investigate...

March 4, 2016, 05:47		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	You could define the plane as a function of the body position using expressions. I can't think of any other way to do it.