Thin fluid film in Ansys

April 11, 2007, 09:53

Dear colleagues,

I have worked on hydrodynamic lubrication (thin fluid film in bearings, seals etc.) that is described by the classical Reynolds equation. There is a thin fluid film between two plates. One of the plates tangentially moves (slides) relatively to the other. In addition, the cavitation regions are possible. Can I solve this problem by ANSYS? In the ANSYS help I have found the Reynolds equation for the squeeze effect only when one of the plates perpendicularly moves (slides) relatively to the other. This don't suit me.

Thank you

Alexey

April 12, 2007, 02:47

Hello Alexey,

You can model lubrication problems including cavitation in ANSYS CFX solving RANS and, if you need, couple it with ANSYS. There is no Reynolds equation in CFX. And, I suppose, this simplified Reynolds model in ANSYS does not take into account cavitation.

Regards, hdj

Feliks · November 11, 2010, 20:29

Greetings,
I'm trying to do something similar as Alexey. I have a stationary wall separated from a rotating wall by a very thin film of air. The rotating wall has a pumping 'cavity' in it and I have been having trouble modeling this w/ CFX. I noticed hdj mentioned solving RANS, any thought on what that means? Any help would be appreciated.
thanks,
Marc

ghorrocks · November 11, 2010, 21:57

RANS = Reynolds averaged Navier Stokes equations.

Feliks · November 12, 2010, 13:22

Thanks,
I researched it in the cfx help files and it appears that RANS equations are the typical equations used and therefore I've already used them. I'm not developing any pressure inside the thin film and I'm wondering if I should be using something other than RANS?

ghorrocks · November 13, 2010, 05:26

CFX solves NS, RANS or LES equations. But for your application if you are using CFX you will use NS equations if it is laminar, RANS if turbulent.

April 11, 2007, 09:53	Thin fluid film in Ansys	#1
Alexay Guest Posts: n/a	Dear colleagues, I have worked on hydrodynamic lubrication (thin fluid film in bearings, seals etc.) that is described by the classical Reynolds equation. There is a thin fluid film between two plates. One of the plates tangentially moves (slides) relatively to the other. In addition, the cavitation regions are possible. Can I solve this problem by ANSYS? In the ANSYS help I have found the Reynolds equation for the squeeze effect only when one of the plates perpendicularly moves (slides) relatively to the other. This don't suit me. Thank you Alexey

April 12, 2007, 02:47	Re: Thin fluid film in Ansys	#2
hdj Guest Posts: n/a	Hello Alexey, You can model lubrication problems including cavitation in ANSYS CFX solving RANS and, if you need, couple it with ANSYS. There is no Reynolds equation in CFX. And, I suppose, this simplified Reynolds model in ANSYS does not take into account cavitation. Regards, hdj

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November 11, 2010, 20:29		#3
Feliks New Member Join Date: Nov 2010 Posts: 2 Rep Power: 0	Greetings, I'm trying to do something similar as Alexey. I have a stationary wall separated from a rotating wall by a very thin film of air. The rotating wall has a pumping 'cavity' in it and I have been having trouble modeling this w/ CFX. I noticed hdj mentioned solving RANS, any thought on what that means? Any help would be appreciated. thanks, Marc

November 11, 2010, 21:57		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	RANS = Reynolds averaged Navier Stokes equations.

November 12, 2010, 13:22		#5
Feliks New Member Join Date: Nov 2010 Posts: 2 Rep Power: 0	Thanks, I researched it in the cfx help files and it appears that RANS equations are the typical equations used and therefore I've already used them. I'm not developing any pressure inside the thin film and I'm wondering if I should be using something other than RANS?

November 13, 2010, 05:26		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	CFX solves NS, RANS or LES equations. But for your application if you are using CFX you will use NS equations if it is laminar, RANS if turbulent.