Evaluation of a diffuse interface treatment for pressure in phase change simulations using adaptive mesh refinement

Phase change computational simulations using a diffuse interface treatment for pressure were investigated in order to quantify the spurious currents and its consequences on the interface transport in the present paper. In addition, benchmarks were conducted with a sharp interface treatment for pressure. Namely, a Delta function method (Delta) was employed for the diffuse interface treatment and a ghost fluid method (GFM) for the sharp approach. An additional force term in the non-divergent form of the momentum equation is proposed for the first time in the literature, and its impact on interface motion during simulations of bubble growth by intense phase change has been quantified. In addition, the influence of recoil force on interface position was evaluated in simulations of water bubble condensation at near critical pressure. Finally, simulations of a complex industrial application were performed using the diffuse interface treatment, namely a case of film boiling with the development of Rayleigh–Taylor instability. Both interface treatments presented excellent results for the interface evolution in time. Even with the presence of some relevant spurious currents in the Delta method, the bubble evolution in time was accurately predicted. The sharp interface treatment potential was especially evident using a mass density flux of 1.0 kg/(m2 s) or higher. Therefore, a diffuse interface treatment for pressure has been presented as an appropriate strategy for most phase change simulations since the presence of the spurious currents did not disturb the interface position, and its magnitude was low for even moderate phase change intensities. The inclusion of the source term due to the additional force in the non-divergent form of the momentum equation and the recoil force term was irrelevant in the cases tested. Lastly, the film boiling simulation using the diffuse interface treatment revealed the possibility of treating complex 3D cases for industrial applications with this method.