Numerical modeling of axisymmetric and three-dimensional flows in MEMS nozzles

Abstract

A numerical study of three-dimensional effects on the performance of a micronozzle fabricated from flat silicon wafer is performed by both continuum and kinetic approaches. The nozzle operates in a low Reynolds numbers regime and viscous effects dominate the gas expansion. Thrust losses occur because the shear on the wall is greater in the nozzle of a flat configuration compared to an axisymmetric conical nozzle. Therefore, the prediction of the micronozzle performance based on axisymmetric or two-dimension al modeling can lead to significant design errors.