# Porosity setting in CFX for a specific problem

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April 16, 2019, 07:08
Porosity setting in CFX for a specific problem
#1
Member

Abdullah Arslan
Join Date: Apr 2019
Posts: 91
Rep Power: 3
Hi All,
My Qs are:
#1. How can I put interfacial area density with such data
#2. How to compute Resistance loss coefficient Kloss

I am performing heat Transfer analysis on a 2 square channel.
I am trying to derive from the attached file data for CFX porosity tab.
The information I have is volume porosity, permeability, pore diameter, fibre diameter, PPI, inertial loss coefficient (Cf).
Values needed to be input are i)Volume porosity (phi), ii)Velocity type, iii) Permeability (K) and loss coefficient(Kloss), iv)Interracial area density
1. Straight forward
2. Superficial for now as calculation is more realistic
3. Permeability: though value is high but i put as it is. Moreover, it causes no impact on heat transfer and velocity profile even if value is changed 10 order magnitude (decrease or increase).
Loss coefficient is Resistance loss coefficient (Kloss) (1/m) and given in paper is Inertial loss coefficient (no unit). In paper it is given as b=rho*Cf/(sqrtK) of quadratic term. it can be compared to b=Kloss*rho/2 given in CFX theory guide. So Kloss=2*Cf/(sqrtK). Still results are unsatisfactory and I am doubting K value as it is very high K=1.2
4: Formula is 6*(1-phi)/Dp where Dp is particle diameter of foam converted into sphere particle (Dp not pore diameter). For this case any value greater than zero diverging my result from paper but I am using zero for matching results (but in reality there should be at least some value other than zero)

Attached Images
 Porous medium data.jpg (58.7 KB, 7 views)

Last edited by Goenitz; April 17, 2019 at 05:20. Reason: Putting Qs

April 16, 2019, 07:47
#2
Member

Abdullah Arslan
Join Date: Apr 2019
Posts: 91
Rep Power: 3
Pic of my problem.

https://www.eureka.im/2409.html
Very good info indeed, BTW
Attached Images
 Porosity settings.jpg (87.9 KB, 10 views)

 Tags cfx, interfacial area density, porous