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-   -   Heat Exchanger (http://www.cfd-online.com/Forums/star-ccm/94292-heat-exchanger.html)

hamzamotiwala November 11, 2011 04:09

Heat Exchanger
 
Hello everyone,

I am working on a heat exchanger model which is a part of an exhaust gas recirculation system.

I define this part as a seperate porous region(so that I can restrict the flow in certain directions and also sort of create a baffle/airfilter effect) and what I am trying to do is to reduce the exit temperature of the air that enters this region.

I just define this region as a Heat exchanger.

I have tried this by giving in a fixed wall temperature and i have also tried this with the help of the "Energy transfer option". I also specify the exit temperature. I just cant get it right.

The temperature of the air at the inlet is about 350K and I want this to reduce to 320K. There is no second working fluid. The Problem is that the air always cools to a temperature below 0K within the porous region. I have tried giving in a wide range of values and its always some sort of negative temperature profile that I get. I know I am doing something wrong.

If anyone has any idea about whats happening here, I would really appreciate some advice.

If you want more specifications I can provide it or if I am not clear enough I can elaborate.

Thanks,
Hamza


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