Two-phase Flows and Turbulence Models

Bcan · September 6, 2010, 05:28

Hello,

I am tring to model a two-phase flow which gas is turbulent and the liquid is laminar. However fluid tends to breakup instead of forming a film when the turbulence model is activated.

Is there a way to activate turbulence for one of the fluids and not for the other?

Thanks for your help

MuxaB · September 10, 2010, 21:49

I am afraid there is no way to do it. I suggest turning turbulence off all together to maintain a stable interface

Bcan · September 11, 2010, 07:28

Hello MuxaB,
Thank you for your reply.. I have tried that.. it gives me a stable interface however the velocity profiles, pressure distribution and shear rate between fluids are completely off compared to experimental results.. And the problem is we are intrested for both of these profiles...
I can get more reasonable profile modifying the turbulence mixing length.. Do you think it would be possible to define turbulence for only one fluid writing a user input file?
It is quite disappointing that we have to define turbulence model for both fluids..

Thanks..

MuxaB · September 11, 2010, 12:28

You'd have to modify the code for it, which is possible if you have Intel 9.1 FORTRAN compiler. For example, you can go into the function MUCAL where fluid viscosity is computed and reset it to the molecular value in the liquid.

Alternatively, you could change the subroutine QSADD to reset turbulent energy and dissipation, TKE and DTKE to the default levels.

Bcan · September 11, 2010, 14:25

I have Intel 9.1 FORTRAN but I haven't really used FORTRAN except writing very simple user input file to ABAQUS couple of years ago, but I will look into those options. Thank you..

September 6, 2010, 05:28	Two-phase Flows and Turbulence Models	#1
Bcan New Member Join Date: Sep 2010 Posts: 3 Rep Power: 15	Hello, I am tring to model a two-phase flow which gas is turbulent and the liquid is laminar. However fluid tends to breakup instead of forming a film when the turbulence model is activated. Is there a way to activate turbulence for one of the fluids and not for the other? Thanks for your help

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September 10, 2010, 21:49		#2
MuxaB Senior Member michael barkhudarov Join Date: Mar 2009 Location: Sante Fe, New Mexico, USA Posts: 336 Rep Power: 18	I am afraid there is no way to do it. I suggest turning turbulence off all together to maintain a stable interface

September 11, 2010, 07:28		#3
Bcan New Member Join Date: Sep 2010 Posts: 3 Rep Power: 15	Hello MuxaB, Thank you for your reply.. I have tried that.. it gives me a stable interface however the velocity profiles, pressure distribution and shear rate between fluids are completely off compared to experimental results.. And the problem is we are intrested for both of these profiles... I can get more reasonable profile modifying the turbulence mixing length.. Do you think it would be possible to define turbulence for only one fluid writing a user input file? It is quite disappointing that we have to define turbulence model for both fluids.. Thanks..

September 11, 2010, 12:28		#4
MuxaB Senior Member michael barkhudarov Join Date: Mar 2009 Location: Sante Fe, New Mexico, USA Posts: 336 Rep Power: 18	You'd have to modify the code for it, which is possible if you have Intel 9.1 FORTRAN compiler. For example, you can go into the function MUCAL where fluid viscosity is computed and reset it to the molecular value in the liquid. Alternatively, you could change the subroutine QSADD to reset turbulent energy and dissipation, TKE and DTKE to the default levels.

September 11, 2010, 14:25		#5
Bcan New Member Join Date: Sep 2010 Posts: 3 Rep Power: 15	I have Intel 9.1 FORTRAN but I haven't really used FORTRAN except writing very simple user input file to ABAQUS couple of years ago, but I will look into those options. Thank you..