OpenFOAM - three phase oil-water interceptor

foamF · May 14, 2019, 03:41

Hi, I am doing a simulation of a three phase oil-water interceptor with OpenFOAM, using multiphaseInterFoam as the solver and kOmegaSST as the turbulence model.

The simulation runs normally until few to ten seconds (and the results look physically reasonable), then the model crashes. After many trials, I still could not figure out the problems. The model setup is simple with an inlet, 3 outlets, solid walls and symmetry plane (for cutting the object into a half).

For inlet, I used fixedValue for U and fixedFluxPressure for p_rgh. BCs for alpha.air, alpha.oil and alpha.water are 0, 0.5 and 0.5 respectively.

For the outlet at the top (for gas release), I used pressureInletOutletVelocity for U and totalPressure. The BCs for alpha.gas, alpha.oil and alpha.water were set to zeroGradient.

For the outlets at the bottom (for oil and water discharge), I used zeroGradient for all BCs.

I guess the BC setup should be fine. Any expert can give some advice on the possible issues and suggest some solutions.

Thanks in advance.

BlnPhoenix · May 15, 2019, 05:12

Did you try running it laminar first?
What exactly blows up during the run?
How's Co looking?

foamF · May 15, 2019, 06:03

Thanks for your reply.

I am trying another run with the BC of the outlet at the top (for gas release) for passage of pure gas only. alpha.oil and alpha.water was set to fixedValue = 0 and alpha.air was set to inletOutlet. It appears to work now.

May 14, 2019, 03:41	OpenFOAM - three phase oil-water interceptor	#1
foamF Member Join Date: Aug 2018 Posts: 47 Rep Power: 8	Hi, I am doing a simulation of a three phase oil-water interceptor with OpenFOAM, using multiphaseInterFoam as the solver and kOmegaSST as the turbulence model. The simulation runs normally until few to ten seconds (and the results look physically reasonable), then the model crashes. After many trials, I still could not figure out the problems. The model setup is simple with an inlet, 3 outlets, solid walls and symmetry plane (for cutting the object into a half). For inlet, I used fixedValue for U and fixedFluxPressure for p_rgh. BCs for alpha.air, alpha.oil and alpha.water are 0, 0.5 and 0.5 respectively. For the outlet at the top (for gas release), I used pressureInletOutletVelocity for U and totalPressure. The BCs for alpha.gas, alpha.oil and alpha.water were set to zeroGradient. For the outlets at the bottom (for oil and water discharge), I used zeroGradient for all BCs. I guess the BC setup should be fine. Any expert can give some advice on the possible issues and suggest some solutions. Thanks in advance.

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May 15, 2019, 05:12		#2
BlnPhoenix Senior Member Join Date: Aug 2014 Location: Germany Posts: 292 Rep Power: 14	Did you try running it laminar first? What exactly blows up during the run? How's Co looking?

May 15, 2019, 06:03		#3
foamF Member Join Date: Aug 2018 Posts: 47 Rep Power: 8	Thanks for your reply. I am trying another run with the BC of the outlet at the top (for gas release) for passage of pure gas only. alpha.oil and alpha.water was set to fixedValue = 0 and alpha.air was set to inletOutlet. It appears to work now.