homogeneous turbulence model for inhomogeneous multiphase flow simulations？

TerryNiu · March 4, 2018, 20:51

Hi friends!

Why cfx will recommend me to select homogeneous turbulence model for inhomogeneous multiphase flow simulations？

It said"It is recommended that a homogeneouos turbulence model is used for inhomogeneous multiphase simulations with more than one continuous phase"

ghorrocks · March 5, 2018, 04:33

Where does it say that?

TerryNiu · March 6, 2018, 00:32

Quote:

Originally Posted by ghorrocks

Where does it say that?

In CFX help-Modeling Guide-Multiphase Flow Modeling-Modeling Advice for Multiphase Flow

It said: For flows in which the phases tend to separate (for example, inhomogeneous free surface flows and oil-water separators), the homogeneous turbulence model is recommended.

Obviously, oil and water are not two mutually soluble liquids, why homogeneous turbulence model is recommened?

Thanks

Gert-Jan · March 6, 2018, 04:24

Homogeneous means that CFX will apply the same turbulence model in each phase. So laminar, k-e, SST, RSM, whatsoever: in both phases the same turbulence model. For a case where oil and water are separated (inhomogeneous), it is safe to use this.

You can overrule this if you want. If you have good reasons to do so,

TerryNiu · March 6, 2018, 23:22

Quote:

Originally Posted by Gert-Jan

Homogeneous means that CFX will apply the same turbulence model in each phase. So laminar, k-e, SST, RSM, whatsoever: in both phases the same turbulence model. For a case where oil and water are separated (inhomogeneous), it is safe to use this.

You can overrule this if you want. If you have good reasons to do so,

Oh I see now. That means each phase will obey the same turbulence model, isn't it?
Thanks for your detailed explaination!

ghorrocks · March 6, 2018, 23:52

It means more than sharing the same turbulence model. It means all phases will share the same turbulence field as well. So if one phase has k=10 at some location then all phases have k=10 at that location.

TerryNiu · March 7, 2018, 01:00

Quote:

Originally Posted by ghorrocks

It means more than sharing the same turbulence model. It means all phases will share the same turbulence field as well. So if one phase has k=10 at some location then all phases have k=10 at that location.

Thank you very much!

March 4, 2018, 20:51	homogeneous turbulence model for inhomogeneous multiphase flow simulations？	#1
TerryNiu New Member Terry Join Date: Jan 2018 Posts: 16 Rep Power: 8	Hi friends! Why cfx will recommend me to select homogeneous turbulence model for inhomogeneous multiphase flow simulations？ It said"It is recommended that a homogeneouos turbulence model is used for inhomogeneous multiphase simulations with more than one continuous phase"

March 5, 2018, 04:33		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Where does it say that? __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

March 6, 2018, 23:52		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	It means more than sharing the same turbulence model. It means all phases will share the same turbulence field as well. So if one phase has k=10 at some location then all phases have k=10 at that location. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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March 6, 2018, 04:24		#4
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,827 Rep Power: 27	Homogeneous means that CFX will apply the same turbulence model in each phase. So laminar, k-e, SST, RSM, whatsoever: in both phases the same turbulence model. For a case where oil and water are separated (inhomogeneous), it is safe to use this. You can overrule this if you want. If you have good reasons to do so,