Simulating both solid and fluid regions

ryan.kong62@gmail.com · April 14, 2020, 00:03

Hi All,

I want to simulate the heat transfer of a liquid LBE in a closed loop. The geometry is a little bit complicated. I have generated the solid structure using Solidworks. How should I extract the internal volume for the fluid domain and mesh both the solid and fluid volumes?

Thanks,

Ran

LuckyTran · April 14, 2020, 04:55

You can do it in either solidworks or star-ccm. Create a water-tight solid and subtract your solid from it. In solidworks, you find it in create mold iirc.

ryan.kong62@gmail.com · April 14, 2020, 11:18

Hi LuckyTran,

Thank you for your reply. I did it in Star CCM using "extract internal volume". However, when I mesh the parts, it keeps telling me that "patch is shared by more than two part surfaces". I understand that I may need to do the surface repair. I have studied the manual but I still have no clue how to do it.

One question is when I use "extract internal volume" in Star CAD, does it generate two faces at the interface? one belongs to solid and the other one belongsto fluid? What about "subtract"? Does "subtract" also generate two faces?

Quote:

Originally Posted by LuckyTran

You can do it in either solidworks or star-ccm. Create a water-tight solid and subtract your solid from it. In solidworks, you find it in create mold iirc.

LuckyTran · April 15, 2020, 03:03

How about... we don't open a can of worms.

I recommend you try on a simple geometry like a cylinder in a box to clear some of your doubts.

ping · April 16, 2020, 01:42

since you created your cad in swx it should be in a good condition compared to some of the dodgy surfaces some users have to use.
i suggest you import into the cad tool of star ie open a new blank cad model and import the swx parasolid part. ensure you use parasolid and not some inferior cad translated format since star like swx uses parasolid for solid modelling.
then do the internal volume extraction in cad and then imprint the two bodies onto each other since this creates the required contacts between the two contacting surfaces of the solid bodies.
then transfer the bodies into geometry and there is a good chance that you will have no problems.
avoid surface repair other than for finding where your problems are and then fixing them back in cad or with better mesher settings - only repair when you really do have bad cad in the first place.

April 14, 2020, 00:03	Simulating both solid and fluid regions	#1
ryan.kong62@gmail.com New Member asdf Join Date: Dec 2019 Posts: 2 Rep Power: 0	Hi All, I want to simulate the heat transfer of a liquid LBE in a closed loop. The geometry is a little bit complicated. I have generated the solid structure using Solidworks. How should I extract the internal volume for the fluid domain and mesh both the solid and fluid volumes? Thanks, Ran

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April 14, 2020, 04:55		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,763 Rep Power: 66	You can do it in either solidworks or star-ccm. Create a water-tight solid and subtract your solid from it. In solidworks, you find it in create mold iirc.

April 15, 2020, 03:03		#4
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,763 Rep Power: 66	How about... we don't open a can of worms. I recommend you try on a simple geometry like a cylinder in a box to clear some of your doubts.

April 16, 2020, 01:42		#5
ping Senior Member Ping Join Date: Mar 2009 Posts: 556 Rep Power: 20	since you created your cad in swx it should be in a good condition compared to some of the dodgy surfaces some users have to use. i suggest you import into the cad tool of star ie open a new blank cad model and import the swx parasolid part. ensure you use parasolid and not some inferior cad translated format since star like swx uses parasolid for solid modelling. then do the internal volume extraction in cad and then imprint the two bodies onto each other since this creates the required contacts between the two contacting surfaces of the solid bodies. then transfer the bodies into geometry and there is a good chance that you will have no problems. avoid surface repair other than for finding where your problems are and then fixing them back in cad or with better mesher settings - only repair when you really do have bad cad in the first place.