# Weighted average volume fraction

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 January 22, 2007, 15:46 Weighted average volume fraction #1 Yasser Guest   Posts: n/a 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

 January 26, 2007, 15:41 Re: Weighted average volume fraction #2 Yasser Guest   Posts: n/a i didn't solve my problem yet anyone can help

 April 30, 2010, 18:08 #3 New Member   Tantular Nurtono Join Date: Mar 2010 Posts: 8 Rep Power: 9 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.

May 1, 2010, 21:49
#4
New Member

Inra Sumahamijaya
Join Date: May 2010
Posts: 4
Rep Power: 9
Quote:
 Originally Posted by tantular 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

 May 20, 2010, 21:19 #5 New Member   Inra Sumahamijaya Join Date: May 2010 Posts: 4 Rep Power: 9 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. rgd likes this.

 April 11, 2015, 08:25 #6 New Member   Join Date: Feb 2015 Posts: 5 Rep Power: 4 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. P.S: My udf's are already compiled and loaded. Please reply at soumendu.dasgupta@gmail.com Thanks

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