A sharp-interface phase change model for a mass-conservative interface tracking method

A new phase-change model has been developed for a mass-conservative interface tracking method. The mass transfer rate is directly calculated from the heat flux at the liquid-vapor interface, and the phase change takes place only in the cells which include this interface. As a consequence of the sharpness of the mass transfer rate distribution, the velocity jump across the interface can be captured, and high accuracy can be maintained. The method has been implemented in an incompressible Navier-Stokes equations solver employing a projection method based on a staggered finite-volume algorithm on Cartesian grids. The model has been verified for one-dimensional phase-change problems and a three-dimensional simulation of a growing vapor bubble in a superheated liquid under zero gravity condition. The computed results agree with theoretical solutions, and the accuracy of the model is confirmed to be of second-order in space using a grid refinement study. A three-dimensional simulation of a rising vapor bubble in a superheated liquid under gravity has been performed as a validation case, and good agreement with experimental data is obtained for the bubble growth rate. As a demonstration of the applicability of the method to engineering problems, a nucleate boiling simulation is presented with a comparison to experimental data. Good agreement is obtained for the bubble shapes and the bubble departure period. In all the simulation cases, strict mass conservation is satisfied.