Interface advection due to pure phase change

Hi, I am simulating vaporisation of the liquid column present in a glass tube. In this case, there is a temperature gradient above the liquid (gas region), and due to heat diffusion, the interface temperature reaches T > Tsat, hence vaporization. This setup is similar to the Stefan problem, except that the liquid is not moving, but vapor must move out of the domain. When I ran the above case, I observed that the interface could not transit from the first cell to the next cell due to vaporization.

Furthermore, I checked the advector function; there is a way to distribute the excess fluid (boundFlux function) to down-wind-cells by adjusting the fluxes at the faces. This comes into action if the alpha > 1. However, if the alpha < 0, which occurs in the above example, the alpha is set to zero. So, is there a different algorithm to handle alpha < 0? or it has to be added by the user.

Thank you

DLR-RY / TwoPhaseFlow

Interface advection due to pure phase change #50