Simulation of microchannel flows using a 3D height function formulation for surface tension modelling

Simulations of multiphase flow and phase change heat transfer in microchannels require accurate calculation of the surface tension force to provide accurate interface locations and to avoid spurious velocities that distort the flow at the interface. Building on previous work, where we implemented a 2D height function technique, the 3D height function method has been modified and implemented in ANSYS Fluent to enable such calculations to be performed on structured meshes. Firstly, simulations are presented for test cases that demonstrate the correct and accurate calculation of the surface tension force. Then the model is used to investigate both Taylor bubble formation in a square section channel and the development of an elongated vapour bubble from a small spherical nucleated bubble in a heated channel.