Who can help me with orthotropic resistance
hello, everyone
I am a freshman in CFD. i want to calculate the flow resistance of monolith according to the equation which is provide in STARCD methodology volume, but i meet some trouble. anyone can give some hints to solve this trouble. In the methodology volume of Star CD(in Chapter 8,Example 2), it gives a formula to calculate the friction factor. in this equation, how to get the value of C1, C2 and n? Can I calculate the flow resistance of monolith by ergun equation ? but ergun equation is derived for isotropic resistance! thank you in adavance 
Look for some engineering books on hydraulics  as it is written in the Methodology, these coefficients come from simple relations for "hydraulic resistance" vs Reynolds number. You'll need to calculate Reynolds number for the single channel within your monolith.

A while back I did some automotive catalyst modeling. I directly calculated the A & B coefficients for the channel direction from the measured pressure drop vs. flow rate curve (eq. 81 & 82). I then set the orthogonal direction's coefficients to arbitrarily large values (4 orders of magnitude larger).
I was also able to replicate the pressure drop vs flow rate curve by computing the pressure drop along one representative channel. For this you need to be careful with appropriately capturing inlet & exit losses. Follow the useful points for relative values and limits on the B coefficient. The online help (NavCenter help button once inside the porous media panel) has a decent summary. Make sure you understand the superficial velocity concept. 
Quote:
Thanks for you answerm,would you please tell me the title of this kind book? does you mean I must calculate the reynold number for single channel and then derive the formula for porosity factor 
Quote:

Quote:
thank you very much for your quick response. according to your comment, I could deal with monolith channel as a simple pipe to calculate the pressure loss of the whole monolith without considering the monolith porosity. That is to say, the pressure loss caused by friction in the monolith is only related to the parameter of the monolith channel, and has nothing to do with the monolith porosity. Can I understand your comment in this way ? By the way if I take ), I can not get . Thanks again! 
Quote:
And yes, I've screwed with a math a little bit :) 
I understand it .
thank you very much 
Have you tried using STAR CCM+ for the pressure curve? You can use field functions and other polynomial functions or tables for modelling the alpha and beta (or A and B). You can also accomodate the porosity accordingly or have something to the effect of C2 and alpha that Fluent uses.
STAR CD may not be able to do this directly, but you can get these effects using some user subroutines in STAR CD. 
All times are GMT 4. The time now is 21:14. 