Numerical simulation of annular flow hydrodynamics in microchannels

Annular flow is the dominant flow regime in microchannel flow boiling because it appears at very low vapor quality and persists until dryout at high quality. This flow regime is hydrodynamically unstable, as the phase interfaces are subject to instabilities triggered by flow perturbations. In this work, a computational fluid dynamics (CFD) model is proposed and verified for the studies of annular flow hydrodynamics in microchannels, using the commercial software ANSYS Fluent. Verification of the model is performed by comparing simulation results with existing analytical theories. The potential for the application of this model to microchannel annular flow boiling has been demonstrated.