CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

porous media model validation

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 23, 2016, 05:04
Smile porous media model validation
  #1
Senior Member
 
James
Join Date: May 2013
Posts: 116
Rep Power: 13
Tensian is on a distinguished road
Dear all,

I have a question regarding porous media model in FLUENT. Well, to be fair, more than one question.

I would like to compute pressure drop in a filter in 3D(in the complete geometry and across the filter) using porous media approach in FLUENT. So I need permeability in order to obtain viscous resistance (porosity epsilon is available).

I have available the lineal velocity vs pressure drop curve (find attached the graph) for a type of coal.

I would like to carry out simulations of a filter based on this material. So I have used the pressure drop and velocity of this curves, and also the dynamic viscosity to obtain permeability via Darcy's law:

delta_P= (mu.U)/alpha where delta_P is pressure drop, mu is dynamic viscosity of the material (water in my case) , U is the velocity in the porous media and alpha is the permeability.

So, here are my questions:

1, For the computations:
For a T=25 ºC and lineal velocity of 12 m/h, pressure drop is about 3169 Pa/m, so if I have a porous media with length 0.998 m, then my delta_P=3169*0.998=3162.662 Pa.

I obtain U dividing flow rate by cross sectional area of the filter.

So, for the computation of permeability,should I use...

alpha=(lineal_velocity*dynamic viscosity)/deltaP per meter

or

alpha=(velocity obtained from flow rate and cross sectional area*dynamics viscosity)/(deltaP_per meter*length of porous media)

2. The most important thing. If I do...

surface integrals---Area weighted average---Pressure in the inlet plane of the porous media=Pin_porous
surface integrals---Area weighted average---Pressure in the outlet plane of the porous media=Pout_porous

delta_P_CFD=Pin_porous-Pout_porous

Then,

delta_P_CFD should be equal (or very similar) to deltaP_permeter*length of porous media????

I am not sure if I a m computing well permeability and I am worried about the way to use the curves attached to validate my FLUENT model.

Really interested in your comments. I am sure the most of you have already used something similar...

Thanks in advance,

Tensian
Attached Images
File Type: png curves.PNG (55.0 KB, 17 views)
Tensian is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Porous Media Model reaction mechanism umairjamil FLUENT 1 July 2, 2016 08:23
LTNE model for partially filled porous media Riki FLUENT 0 June 25, 2015 04:24
local thermal non equilibrium model in porous media adi.ptb Fluent UDF and Scheme Programming 0 November 1, 2014 15:00
How to model granular flow through porous media Axius FLUENT 2 August 7, 2014 10:34
CFX Model for dispersion of gas through a porous media filled with Oil deepmetal CFX 13 November 27, 2010 20:34


All times are GMT -4. The time now is 21:39.