[zeoffle]

Hi

I'm currently trying to simulate phase change phenomena in the tiny cooling channel in a steady state.

In this channel, fluid(methane) enters the liquid and becomes gas in the outlet.

Between the inlet and outlet, the channel wall is heated with heat flux that depends on direction of pipe.

The objective of this simulation is to compare the outlet temperature and pressure drop value when with or without phase change phenomena.

I refer to relate paper and tutorials, and I understand that VOF model is appropriate to simulate the phase change phenomena. [Number of cell : about 4 million, Minimum Orthogonal quality : about 0.2(20%) ]

I set the liquid/vapor property and Evaporation-condensation temperature in the mass transfer menu.

In boundary conditions, I set proper liquid and vapor values in inlet and outlet conditions. (inlet : pressure inlet / outlet : mass flow outlet)

However, after calculating, unrealistic results were acquired. Below are summarized results state.

1. Outlet pressure(Static pressure, Operating pressure is set in 101325 Pa) is a negative value the absolute value is bigger than the operating pressure.
2. The vapor phase consisted only at outlet surface. (I think that it relates to outlet boundary condition. I set 1 at outlet vapor fraction)

About these results, I think that outlet boundary condition is the main cause of this problem.

What do you guys think about? Is there further consideration that I missed?

Plus, If anyone has a similar experience, I want to know the process how to solve this problem.

Thanks.