CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   Porous model (http://www.cfd-online.com/Forums/fluent/48965-porous-model.html)

jack August 5, 2008 10:29

Porous model
 
Hello, I am using the porous model of fluent for heat exchanger. I am using NTU model, fixing the heat rejection value. I set all values for the core porous model, following some results that I found with some other program like pressure drop, area. I am quite sure of this values that I input. The core friction factor was actually my only unknown that I calculate by those values. My problem is that, by post processing, I found out a pressure drop of 0.5 bars in my primary gas through the HE when I set a porous model for the heat exchanger based on a pressure drop of 100Pa. Lets say almost a coefficient of 1000. Again, I checked my values. And when you set the heat exchanger model in define, it actually affects the values of inertial resistance in the BC of the volume corresponding to the heat exchanger. After doubting of me, I allow myself to assume that it could have an error in the equation of this porous model. Is there anyone who had got the same pressure drop as he was expected using this NTU model with fluent? Please I am really screwed, so ur help will be welcome. By the way I am using fluent 6.3 Thank u in advance.


jack August 6, 2008 08:20

Re: Porous model
 
I am using K-epsilon model realizable. the heat rejection is fine, temperature are OK. So it has to come from the core porous model. What can I forget in my setting of this model? thanks for ur help.

jack August 11, 2008 04:16

Re: Porous model
 
I am using my own values for the core porosity model. I am having a deltaP across my HE of 500 to 1000 times more than expected. The geometry of HE model is 23 pass, 6rows by pass, 1 column by pass. Auxiliary fluid inlet direction +Y, pass to pass direction +Z. When I apply the model I can see in the porous zone tab of the Boundary conditions that direction 1 is X, and direction 2 is Y and that I have only inertial resistance in direction 2 and 3 with a value which seems 1000 times more important. I hope you understand my problem.


All times are GMT -4. The time now is 02:13.