Operating density (UDF?) multiphase problem

GM_XIII · April 22, 2014, 08:04

Hi all,

I am trying to model a multiphase flow clearly dominated by floatability and it clearly depends on the operating density specified. I've read some say is better to set it to the density of the lightest phase but that doesn't seem accurate to my problem. So i would like to model it with a UDF, is this possible? I think no.

note: i am suing the mixture model

Thanks in advance for your opinion

GM_XIII · July 10, 2014, 08:11

It's been some time but if someone has similar issues. The best for me was setting the reference density to 0. When you activate gravity, your pressure boundary conditions are P(BC)=Ptotal-Preference-rho0(reference density)*g*z(of the face centroid). So in order to define a constant gauge pressure the best practice is to set reference density to 0. Fluent does the above described becouse of roundoff errors, take it in count.

Regards

April 22, 2014, 08:04	Operating density (UDF?) multiphase problem	#1
GM_XIII Member David Join Date: Aug 2012 Posts: 48 Rep Power: 14	Hi all, I am trying to model a multiphase flow clearly dominated by floatability and it clearly depends on the operating density specified. I've read some say is better to set it to the density of the lightest phase but that doesn't seem accurate to my problem. So i would like to model it with a UDF, is this possible? I think no. note: i am suing the mixture model Thanks in advance for your opinion Last edited by GM_XIII; April 23, 2014 at 03:06.

July 10, 2014, 08:11		#2
GM_XIII Member David Join Date: Aug 2012 Posts: 48 Rep Power: 14	It's been some time but if someone has similar issues. The best for me was setting the reference density to 0. When you activate gravity, your pressure boundary conditions are P(BC)=Ptotal-Preference-rho0(reference density)gz(of the face centroid). So in order to define a constant gauge pressure the best practice is to set reference density to 0. Fluent does the above described becouse of roundoff errors, take it in count. Regards ghost82, Debanand, thermal energy and 2 others like this.

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