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

Simulating Heat Exchanger as a Porous Domain

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 12, 2019, 12:30
Question Simulating Heat Exchanger as a Porous Domain
  #1
New Member
 
Gabriel Tunoda
Join Date: Mar 2019
Posts: 2
Rep Power: 0
gabrieltunoda is on a distinguished road
Hello everybody.

I'm trying to analyze the flow on the shell side of a heat exchanger, however, due to the difficulty of modeling the mesh near the various tubes of the model, the idea of ​​representing the region with tubes as a porous domain appeared.
First, to define the permeability as a function of velocity, I created a periodic model of the finite region to verify what the average velocity would be by varying the pressure difference.



Once the average velocity was obtained (as a function of the pressure difference), I created a model of a porous domain equivalent to the periodic one and found what would be the required permeability to obtain the same average velocity with the same pressure difference.
Therefore, a function of Kx (u), Ky (v) and Kz (w) was obtained.



Now, I'm having difficulty in applying these functions to the complete model. How can I apply this function so that the permeability varies in each mesh element according to local speed?
Note: For this analysis I am disregarding the thermal exchange effects.

Thank you in advance.
Attached Images
File Type: png Capture.PNG (94.4 KB, 12 views)
File Type: png Capture2.PNG (38.2 KB, 9 views)
gabrieltunoda is offline   Reply With Quote

Old   March 13, 2019, 08:52
Default
  #2
Senior Member
 
Erik
Join Date: Feb 2011
Location: Earth (Land portion)
Posts: 1,188
Rep Power: 23
evcelica is on a distinguished road
I would think a loss coefficient would be applicable as well. Permeability is the linear part of the loss equation, Kloss is the quadratic part.

Look up the function for pressure drop in the documentation, it has velocity in it.


Something like:

dP/dL = (mu/Permeability)*V + (Kloss/2)*rho*V^2

There are directional multiplier model you can use for changing the characteristics in each direction.
evcelica is offline   Reply With Quote

Old   March 21, 2019, 12:42
Default
  #3
New Member
 
Gabriel Tunoda
Join Date: Mar 2019
Posts: 2
Rep Power: 0
gabrieltunoda is on a distinguished road
Thank you very much for your attention. It worked here. Initially I was concerned about how to represent the permeability "K" and did not check the other input methods. The linear and quadratic coefficients were directly obtained in the first periodic model already based on the "Vmed" vs. "dp" curve.
Thanks again.
gabrieltunoda is offline   Reply With Quote

Reply

Tags
heat exchanger, permeability, porous domain

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
heat exchanger with porous media styx OpenFOAM Pre-Processing 2 August 28, 2017 07:01
convergenceof natural convection prob. in cfx cpkewat CFX 15 January 31, 2014 07:29
injection problem Mark New FLUENT 0 August 4, 2013 02:30
Heat transfer thorugh porous kmgraju CFX 3 December 15, 2012 00:22
Heat transfer in porous domain CFX V12 Hashmi CFX 0 August 15, 2009 13:05


All times are GMT -4. The time now is 09:25.