Why isn't the Kunz model in OpenFOAM 3-phase following the 20O0 reference paper?

spacecat · August 14, 2023, 06:32

Hi,

I was reading the OpenFOAM cavitation Kunz model reference paper and if I did not misunderstand, the paper talks about 3-phase flow (liquid, vapor, and non-condensable gas). Yet, when I looked at the modelled equations in the solver code in OpenFOAM v10 for the Kunz model it seems to be 2-phase flow. Is there a reason why OpenFOAM does not employ the 3-phase flow Kunz model?

Thank you very much in advance!

humber11 · August 20, 2023, 08:02

I don't know that article, but in the whole HEM formulation, it assumes a non-condensable gas. However, when a non-condensable gas is present, it slows down cavitation. Additionally, for stability, it's often assumed that the pressure of the non-condensable gas is equal to the gas pressure. Maybe OpenFoam assumes that within a certain pressure range, all the gas can cavitate without the influence of another phase.

August 14, 2023, 06:32	Why isn't the Kunz model in OpenFOAM 3-phase following the 20O0 reference paper?	#1
spacecat New Member spacecat Join Date: Jul 2023 Posts: 1 Rep Power: 0	Hi, I was reading the OpenFOAM cavitation Kunz model reference paper and if I did not misunderstand, the paper talks about 3-phase flow (liquid, vapor, and non-condensable gas). Yet, when I looked at the modelled equations in the solver code in OpenFOAM v10 for the Kunz model it seems to be 2-phase flow. Is there a reason why OpenFOAM does not employ the 3-phase flow Kunz model? Thank you very much in advance!

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August 20, 2023, 08:02		#2
humber11 New Member Humberto Join Date: Mar 2021 Location: Brasil Posts: 24 Rep Power: 5	I don't know that article, but in the whole HEM formulation, it assumes a non-condensable gas. However, when a non-condensable gas is present, it slows down cavitation. Additionally, for stability, it's often assumed that the pressure of the non-condensable gas is equal to the gas pressure. Maybe OpenFoam assumes that within a certain pressure range, all the gas can cavitate without the influence of another phase.