Learning Forum

[abhnv_01]

I am working with 2-D transient simulation with compressible flow, gravity assisted.

I am using VOF- multiphase model and evaporation condensation model as the phase change model, with saturation temperature as a function of saturation pressure.

liquid is primary phase and Vapor is secondary phase.

liquid properties - piece-wise polynomial function of temperature

vapor density - Ideal gas

vapor viscosity and thermal conductivity - piece-wise poly function of temperature.

Operating pressure - 0, gauge pressure - 76043 Pa

Operating density - 0 kg/m3

Pressure in my domain is constantly increasing, what can be the possible reasons for it?

[Rob]

If the liquid is evaporating where does it go? There should be an equilibrium at some point, but the solver may take a while to get there. Google "BLEVE" for what happens if the tank isn't strong enough.

[abhnv_01]

Liquid is evaporating and vapor bubbles are being generated. But the pressure keeps on rising.
My experience on compressible flow is less, so I am not able to rectify the issue as of now.
Few parameters that I am focusing on ;
Vapor Density (Ideal gas law), Operating pressure, Operating density
Does "reference values" effect the temperature field and pressure field inside the system?

[Rob]

Reference values are for some of the coefficients. Pressure will rise until the system reaches equilibrium, if your pressure is still rising either the model is going wrong, or if the temperature is still rising it's not reached equilibrium.

[abhnv_01]

Thank you for the reply.
I ran the simulation for even longer time. After 15seconds, the system has reached a pressure of 6 bar, which I feel is too high for a miniature closed domain system.
What can be the possible reasons for this pressure increase?