Granular Temperature?

g0dmaphia · July 7, 2010, 12:49

Hi i have a problem with a 3d simulation of an high pressurized bottle (70 bar) discharging a powder into an engine bay (modelled as a big cilynder). The model i use is a Mixture model with Nitrogen Ideal and this powder as 2nd phase (patched at the end of the bottle, near the exit nosel)... the problem is that when i start the simulation i always get high temperatures and the solution diverges immediatly.

I think it is related with the granular temperature of the powder, cause i don´t know what is it and what should be a good value to set...

I think that the mesh is good, it is HEXA with determinants all over 0.3 and angles over 27°...

Thanks in advance

Goldsstean · July 8, 2010, 10:24

Granular Temperature is not temperature. It is the kinetic energy posses by the particle before collussion

g0dmaphia · July 8, 2010, 10:40

yes i know, but i don´t know what is a good value for my case... i thought that setting a strange value could screw up my simulation and let fluent going nuts (high temp, high viscosity ratios and so on)..

Default value is 0.0001 but i don´t know if it is good or not for my simulation, do you have any experience with granular flow? My particles are really small, something like 5 micrometers...

Thanks

July 7, 2010, 12:49	Granular Temperature?	#1
g0dmaphia New Member Join Date: Jul 2010 Posts: 2 Rep Power: 0	Hi i have a problem with a 3d simulation of an high pressurized bottle (70 bar) discharging a powder into an engine bay (modelled as a big cilynder). The model i use is a Mixture model with Nitrogen Ideal and this powder as 2nd phase (patched at the end of the bottle, near the exit nosel)... the problem is that when i start the simulation i always get high temperatures and the solution diverges immediatly. I think it is related with the granular temperature of the powder, cause i don´t know what is it and what should be a good value to set... I think that the mesh is good, it is HEXA with determinants all over 0.3 and angles over 27°... Thanks in advance

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July 8, 2010, 10:24		#2
Goldsstean Member Amol Ramteke Join Date: May 2009 Location: Kolkata Posts: 30 Rep Power: 16	Granular Temperature is not temperature. It is the kinetic energy posses by the particle before collussion

July 8, 2010, 10:40		#3
g0dmaphia New Member Join Date: Jul 2010 Posts: 2 Rep Power: 0	yes i know, but i don´t know what is a good value for my case... i thought that setting a strange value could screw up my simulation and let fluent going nuts (high temp, high viscosity ratios and so on).. Default value is 0.0001 but i don´t know if it is good or not for my simulation, do you have any experience with granular flow? My particles are really small, something like 5 micrometers... Thanks