Multiphase - Define pressure for 1 phase

melona · March 15, 2020, 12:42

I would like to set the pressure of one of my phases in multiphase simulation for the whole fluid region during the whole transient simulation. Can someone tell me how I can define this in ANSYS Fluent, please?

I got 2 phases. The pressure of one of these (air) causes divergence problems but is not of interest. I want to assume that this pressure is constantly ambient pressure to stabilize the calculation. I can't find an option for this. Does anyone have an idea?

vinerm · March 15, 2020, 13:15

In a multiphase simulation, pressure is shared across the phases, i.e., pressure is defined for the mixture and not for the phases. So, you cannot set pressure for one phase. If you're observing divergence due to pressure, then there is some issue with the setup or initialization. As far as air is concerned, gauge pressure within this phase would anyway be more or less close to 0 Pa.

March 15, 2020, 12:42	Multiphase - Define pressure for 1 phase	#1
melona New Member Join Date: Mar 2020 Posts: 7 Rep Power: 6	I would like to set the pressure of one of my phases in multiphase simulation for the whole fluid region during the whole transient simulation. Can someone tell me how I can define this in ANSYS Fluent, please? I got 2 phases. The pressure of one of these (air) causes divergence problems but is not of interest. I want to assume that this pressure is constantly ambient pressure to stabilize the calculation. I can't find an option for this. Does anyone have an idea?

March 15, 2020, 13:15	Pressure in Multiphase Flow	#2
vinerm Senior Member Vinerm Join Date: Jun 2009 Location: Nederland Posts: 2,946 Blog Entries: 1 Rep Power: 36	In a multiphase simulation, pressure is shared across the phases, i.e., pressure is defined for the mixture and not for the phases. So, you cannot set pressure for one phase. If you're observing divergence due to pressure, then there is some issue with the setup or initialization. As far as air is concerned, gauge pressure within this phase would anyway be more or less close to 0 Pa. __________________ Regards, Vinerm PM to be used if and only if you do not want something to be shared publicly. PM is considered to be of the least priority.

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