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-   -   conjugate heate transfer: thermophysical properties (https://www.cfd-online.com/Forums/openfoam-pre-processing/128087-conjugate-heate-transfer-thermophysical-properties.html)

skuznet January 3, 2014 00:24

conjugate heate transfer: thermophysical properties
 
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Dear FOAMers!

I'm trying to simulate conjugate heat transfer in a simple heat exchanger using chtMultiRegionSimpleFoam. I have a water flowing between heated metallic plates. I was able to set up a case based on examples multiRegionHeater and planeWall2D. In these examples air with perfectGas equation of state is used. When I run it with air, the results look ok, at least qualitatively.

However, I would like to use water instead of air, and perfectGas equation of state can't be used.
I tried to use file thermophysicalProperties from the
/tutorials/heatTransfer/chtMultiRegionFoam/multiRegionLiquidHeater/constant/bottomWater/thermophysicalProperties (which is for transient solver)
instead of the file with air properties, I also changed density limits in the system/fluidDomain/fvSolution.SIMPLE. With this changes I was able to run my case, however the results are not correct. The fluid domain doesn't get heated. The temperature increases only on the boundaries of the fluid domain, inside fluid domain temperature does not change. There is something wrong with my definition of fluid, looks like there is no heat conduction inside fluid.

I wonder if anyone can explain me what do I do if I want to use water instead of air?
Can I use water properties from
/tutorials/heatTransfer/chtMultiRegionFoam/multiRegionLiquidHeater/constant/bottomWater/thermophysicalProperties (which is for transient solver)?
If yes, what else I should change in my case?
It would be great if someone can give me a working example of using chtMultiRegionSimpleFoam with water or any other liquid, not gas.

Thank you!

Nkl May 20, 2015 11:48

Hi! I am experiencing the same problem, did you manage to solve it?

derekm May 21, 2015 18:24

you have for the fluid
Code:

transport      const;
    thermo          hConst;
    equationOfState rhoConst;

irc water doesnt have constant density when you heat it

Nkl June 1, 2015 13:08

Thank you. However, I don't understand why in this file /tutorials/heatTransfer/chtMultiRegionFoam/multiRegionHeater/constant/bottomWater/thermophysicalProperties the same entries valid for air are used.
Should I use icoPolynomial equation of state? It is the only one suggested in case of operating with a liquid.

Regards


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