Okay, so you think that parallel run for this particular boiling case is acceptable and it's not the cause of the diverged result, right?
Alright Sir, please check on the images here, I attached some picture to make you more understand about the case.
For outer one, it is the solid (stainless-steel), and for inner one, it is the fluid (water-liquid). Also, that's also my BC for the inlet condition (re:inner one). For the square in the middle, it is basically fluid too but I made that one to ease me on creating the mesh in the domain. this is the mesh elements and nodes
this is the heated wall at the outer one with the amount of heat flux
this is the inlet for mixture phase
this is the outlet for mixture phase
this is the inlet for liquid phase
this is the outlet for liquid phase
this is the inlet for vapor phase
this is the outlet for vapor phase