3D Fluid-Thermal analysis

[maheshh]

Hi

I am new to Ansys and am having certain difficulties while try to solve a problem.
I am looking to solve a problem concerned with flow and cooling of a solid structure in the wind tunnel. The solid structure is modeled with SOLID87 (thermal element). Heat is being generated inside the solid structure and I am trying to analyze the cooling of this structure over time (transient analysis).

Following are the steps that I have taken:
1. Model the solid and a rectangular enclosure around it to simulate the wind tunnel
2. Use 'Volume Overlap' command
3. I am enforcing all the BCs on the solid model so that I can play with the mesh later on. I am specifying follwoing BCS:
a. Heat flux on an area inside the solid
b. Velocity on one of the sides of the enclosure
c. Make velocity = 0 on sides along the length of the wind tunnel to simulate walls
d. Have kept the outlet of wind tunnel without any BCs (should i be specifying anything here)
e. Specify zero velocity on all the surface of the solid structure.

4. Mesh the solid structure with SOLID87
5. Mesh the enclosure with FLUID142
6. Set FLOTRAN fluid properties: I have set it to AIR-MM as I am using g-mm-sec

I am stuck at this point. I want to solve the thermal and fluid problem together, but I am not able to . If I say RUN FLOTRAN, I get an error message that I cannnot use FLUID elements with any other elements in ANSYS. So I tried selecting only FLUID elements and then hit SOLVE, but ANSYS still does not solve the problem.

Can somebody point out what I am doing wrong? How can I have ANSYS solve thermal - fluid problem together?

Help will be greatly appreciated.

Regards,

Mahesh

 

[maheshh]

Can somebody please give me some inputs here? I am still stuck.

Regards,

Mahesh.

 

[maheshh]

Still stuck!!

 

[asdzzb]

Hello Mahesh,
we can not use an other element with fluid 141 and 142.
you must consider the fluid in the channel and solid both with element fluid 142 with different mat number.

hope help you

 

[juzz]

Hello, mahesh!

Take a look to the Chapter 2 (Sequential couple-field analysis) of the Couple Field Guide from your help.
There you will have a list for the element types that you could use in a multiphysiscs in order to simulate couple-field problems. I think that you need to use SOLID70 with FLUID142 for your simulation. But is the best for you to read and decide what is best for your analysis. I use two years ago the method for a fluid-structure simulation (not involving the thermal aspect). And it works pretty well.

Best regards,
Justin Onisoru
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Scientific Researcher
Romanian Academy - Institute of Solid Mechanics
Ctin Mille 15, P. O. Box 1-863
Bucharest 010141, Romania
tel +40 21 3153810, fax +40 21 3157478
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