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sshoeb42
Posts: 17
Registered: ‎11-26-2012

problem with CAD geometry motion

168 Views, 3 Replies
12-05-2012 08:14 AM

Hi Guys,

 

i am having a problem with simulating the compression in engine cylinder....

 

I am simulating  a motion of piston inside the cylinder chamber both having same diameter...

 

I created the CFD volume on the top of piston...

 

As the piston is moving up, the piston is also creating the CFD volume behind it which is not there in first place and the fluid inside the cylinder is not compressed...

 

Thanking you,

Shoeb.

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wildej
Posts: 874
Registered: ‎08-25-2011

Re: problem with CAD geometry motion

12-05-2012 11:15 AM in reply to: sshoeb42

Best bet is to move the piston out of the cylinder in CAD, then offset it back into the cylinder within CFD using the Initial Position in motion. This way you will have a complete fluid.

 

Bear in mind though that we cannot accurately model the thermal side of the solution within a sealed chamber, depends what you are looking to analyse.



Jon Wilde
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dennycheung
Posts: 2
Registered: ‎04-25-2014

Re: problem with CAD geometry motion

04-25-2014 05:37 AM in reply to: sshoeb42

Hi sshoeb42,

 

Did you ever get that to work? I am having the same problem with it!

 

Thanks,

Denny

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New Member
dennycheung
Posts: 2
Registered: ‎04-25-2014

Re: problem with CAD geometry motion

04-25-2014 07:17 AM in reply to: sshoeb42

Hi Jon,

 

I am having the same issue here. I am modeling a triplex pump, where a piston with reciprocating action is supposed to pressurizing/depressurizing the water in the chamber to cause two check valves to open or close. One of the check valve has a 6000psi behind it and the other one has 50psi. As the piston is in the compression cycle, it doesn't compress the fluid like it should and therefore, the high pressure check valve never open up.

 

Thanks!

Denny 

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