multiphase... solid volume fraction anomaly

April 9, 2008, 00:09

Hi,

When I run a multiphase simulation and proces the results, a contour of the volume fraction of the solid particles results in areas where the volume solid fraction is 1, even though I have put in a maximum volume fraction of 0.62. I have designated seperate velocity fields for the solid particles and the continuous fluid, could this be why? Here are some of the details.

air continuous fluid solid particles 1 mm diameter dispersed, 50% volume fraction k-epsilon turbulence model sato enhanced eddy viscosity restitution coefficient 0.5 gidaspow solid pressure model

Thanks, Tim.

mugenzj · February 13, 2012, 06:47

Hi I am having the same problem too! The initial static solid volume fraction of the bed is equals to 1 despite setting my solid as a dispersed solid. Can some1 please help me out with this issue? Many thanks.

Cluain · February 13, 2012, 11:45

I'm no expert, I’ve only dealt with fluids, but I'd say the simulation did not accept your input and hence you got 1 for one medium and 0 for the other.
The joys of learning CFX

max3.2 · February 13, 2012, 14:57

solver cant guarantee to keep below packing limit. period.
(thats what i got out of thr doc, but it was some time ago...)

mugenzj · February 14, 2012, 05:01

Hmm actually I was thinking whether it has got anything to do with the definition of the "solid volume fraction". Is it the absolute value or is it the value relative to the maximum packing? hmmm.

April 9, 2008, 00:09	multiphase... solid volume fraction anomaly	#1
Tim Guest Posts: n/a	Hi, When I run a multiphase simulation and proces the results, a contour of the volume fraction of the solid particles results in areas where the volume solid fraction is 1, even though I have put in a maximum volume fraction of 0.62. I have designated seperate velocity fields for the solid particles and the continuous fluid, could this be why? Here are some of the details. air continuous fluid solid particles 1 mm diameter dispersed, 50% volume fraction k-epsilon turbulence model sato enhanced eddy viscosity restitution coefficient 0.5 gidaspow solid pressure model Thanks, Tim.

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February 13, 2012, 06:47		#2
mugenzj New Member Join Date: Feb 2012 Posts: 2 Rep Power: 0	Hi I am having the same problem too! The initial static solid volume fraction of the bed is equals to 1 despite setting my solid as a dispersed solid. Can some1 please help me out with this issue? Many thanks.

February 13, 2012, 11:45		#3
Cluain Member Join Date: Oct 2011 Posts: 32 Rep Power: 15	I'm no expert, I’ve only dealt with fluids, but I'd say the simulation did not accept your input and hence you got 1 for one medium and 0 for the other. The joys of learning CFX

February 13, 2012, 14:57		#4
max3.2 Member Max Join Date: Apr 2011 Posts: 47 Rep Power: 15	solver cant guarantee to keep below packing limit. period. (thats what i got out of thr doc, but it was some time ago...)

February 14, 2012, 05:01		#5
mugenzj New Member Join Date: Feb 2012 Posts: 2 Rep Power: 0	Hmm actually I was thinking whether it has got anything to do with the definition of the "solid volume fraction". Is it the absolute value or is it the value relative to the maximum packing? hmmm.