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-   -   Weighted average volume fraction (https://www.cfd-online.com/Forums/fluent/43437-weighted-average-volume-fraction.html)

 Yasser January 22, 2007 15:46

Weighted average volume fraction

Hello,

I am simulating 2-phase solid-liquid flow in mixing tank using Eulerian model. My study concentrate on the concentration of solids in the tank. I have no injections of solids or liquid in the tank (the impeller mixes the 2 phases).

I assumed an initial homogenous mixture with solid volume fraction of 0.04 by patching this value before iteration.

After the solution converged, i found the Weighted average volume fraction is lower than 0.04, it was equal to 0.023.

I tried to turn off the volume fraction equation but,When i turned the volume fraction equation off, the mixture became homogenous as initialized and no particle distribution obtained.

how can i fix the volume fraction of the solid in the whole tank while the concentration still can change??

Thanks for help

 Yasser January 26, 2007 15:41

Re: Weighted average volume fraction

i didn't solve my problem yet

anyone can help

 tantular April 30, 2010 18:08

I have the same problem in solid-liquid mixing tank using the MRF model for impeller rotation. The solid volume fraction becomes lower and lower during the iteration. Please help us. Many thanks.

 inra May 1, 2010 21:49

Quote:
 Originally Posted by tantular (Post 257088) I have the same problem in solid-liquid mixing tank using the MRF model for impeller rotation. The solid volume fraction becomes lower and lower during the iteration. Please help us. Many thanks.
Similar prolem to Thread Starter, I tried to register the solid phase, and patched the registered solid phase with initial 0.04 volume fraction. Still, not solving the problem, the solid volume fraction becomes lower and lower during the iteration. The worse case is, each iteration took me 2 hours to complete!

I'm using Fluent 12.0
Any help would be greatly appreciated

 inra May 20, 2010 21:19

I've overcome those non-constant Volume Fraction during iteration problem.

I was using the steady-state method when i encounter the first problem; But after i try to use unsteady state Transient using simple time step and a few iterations in every time step, i had constant a Volume fraction!

Gladly, i solve one problem. But another problem occur. I have a "cracked" contour in my case. I'll explain clearly in a new thread.

Thank you, Hope that helps.

 soumendu.dasgupta April 11, 2015 08:25

Hi all.

I am new to fluent. Please tell me where to how and where to patch the udf for variation in solid volume fraction in Fluent 15.0.