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Sam0508 February 27, 2012 05:14

Porous Medium
 
Hi,
This is sam from coimbatore,India.I've read the below content.I have a doubt in this, how could i calculate the Dp/L by using CFD sofware.

Let i take pipe Dia 250mm length 2m. The porous region is located at 1m(middle section) porous thickness 0.25m.In this i have to consider either Total pipe length 2m or Porous lg 0.25m for find initial Parameter of Dp/L with diff velocity V m/sec for get the excel plot(K and C2). Anyone can help me

Regard,
Sam

*******************************
The formula is
Dp/L= [(viscosity/alpha)*velocity]+ [C2*1/2*density*velocity^2]
(dp/l =viscousr resistance + inertial resistance)

plot dp/l vs velocity in excel. The pressure drop can be obtained from cfd.

The values for velocity can be arbitrarily chosen say for ex. 0 to 20 m/s (even more if you want more points)

Plot Dp/L vs velocity based on above formula and examine the curve how it looks like. If it is a straight line then use only dp/l=viscous resistance.
If it is a quadratic equation use (dp/l =viscousr resistance + inertial resistance). Find K and C2 with these curves.

Hope this helps .

cheers
Nelly

abdul099 March 7, 2012 19:07

You only have to consider the porous part of your domain, since the straight pipe before and after the porous part is not covered by the Dp/L formula.

It depends on your type of problem whether you can take Dp/l from a CFD simulation or not. Please describe your problem a little more accurately. What parameters do you have? What do you want to know? How does your porous part look like?

Sam0508 March 9, 2012 05:36

Quote:

Originally Posted by abdul099 (Post 348245)
You only have to consider the porous part of your domain, since the straight pipe before and after the porous part is not covered by the Dp/L formula.

It depends on your type of problem whether you can take Dp/l from a CFD simulation or not. Please describe your problem a little more accurately. What parameters do you have? What do you want to know? How does your porous part look like?

Hi Abdul099,
Actually i want to simulate the Pr.drop by CCM+ software itself.

u r saying i've consider where the porous region is present for find Dp value am i right(need not consider the total pipe length)?

u consider above pipe dimension,at middle the cotton matl is present...what will be pr drop effect by cotton matl? and how to do this in CCM+? give me ur idea ..... Adv Thanx






Regards,
Sam0508


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