Porous Jump - metal grid

Bionico · October 28, 2011, 07:45

Hi everybody,
I'm working on a burner (1mm thickness): it's a metal woven grid and I decided to model it with porous jump in Fluent
From an experiment I got these coefficients (quadratic fitting as suggested in the guide):
alfa = 1.4e-10
C2= 450000
I don't know if these are realistic values... what do you think?

Bionico · November 1, 2011, 12:58

Moreover I did a simulation of the experiment with a pipe and the burner inside: to reach the pressure drop measured I had to fix C2 coefficients to 4500: 2 order lower than the computed one from the real experiment!!!!
The permeability should be realistic because the grid is very dense, but I don't know if C2 should be high or low... which data I have to take into account? experimental or simulation ones??
Please help me!

delaneyluke · November 7, 2011, 02:01

According to my experience, the experimental coeef do not always give you the pr drop you need. You need to modify the coeff and it's the C2 that generally varies a lot. As long as you get the pr drop you require in your CFD model, go ahead.

October 28, 2011, 07:45	Porous Jump - metal grid	#1
Bionico Senior Member Flavio Join Date: Sep 2011 Location: Brescia, Italy Posts: 181 Rep Power: 15	Hi everybody, I'm working on a burner (1mm thickness): it's a metal woven grid and I decided to model it with porous jump in Fluent From an experiment I got these coefficients (quadratic fitting as suggested in the guide): alfa = 1.4e-10 C2= 450000 I don't know if these are realistic values... what do you think? Last edited by Bionico; November 1, 2011 at 12:52.

November 1, 2011, 12:58		#2
Bionico Senior Member Flavio Join Date: Sep 2011 Location: Brescia, Italy Posts: 181 Rep Power: 15	Moreover I did a simulation of the experiment with a pipe and the burner inside: to reach the pressure drop measured I had to fix C2 coefficients to 4500: 2 order lower than the computed one from the real experiment!!!! The permeability should be realistic because the grid is very dense, but I don't know if C2 should be high or low... which data I have to take into account? experimental or simulation ones?? Please help me! Last edited by Bionico; November 2, 2011 at 03:08.

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November 7, 2011, 02:01		#3
delaneyluke Senior Member Join Date: Mar 2009 Location: Indiana, US Posts: 186 Rep Power: 17	According to my experience, the experimental coeef do not always give you the pr drop you need. You need to modify the coeff and it's the C2 that generally varies a lot. As long as you get the pr drop you require in your CFD model, go ahead.