Numerical Study of Shock Wave Entry and Propagation in a Contracting Microchannel

Abstract

Entry and propagation of a shock wave with the Mach number Mis = 2.03 in a microchannel is numerically studied with the use of kinetic and continuum approaches for Knudsen numbers Kn � 8 · 10 −3 and Kn � 8 · 10 −2 . The intensity of the shock wave is found to increase after its entry into the microchannel at the Knudsen number Kn � 8 · 10 −3 . Further downstream, the shock wave attenuates, which agrees with experimental data. It is demonstrated that this shock wave enhancement is caused by the high pressure ahead of the microchannel entrance. At the Knudsen number Kn � 8 · 10 −2 , the influence of the microchannel entrance geometry on shock wave propagation along the microchannel is studied. Intense attenuation of the shock wave inside the microchannel is observed for three different geometries of the microchannel entrance: junction of two channels of different sizes, junction of a channel and a microchannel with a splitter plate at the microchannel entrance, and junction of a channel and a microchannel via a rounded sector with an angle of 90 � . It is demonstrated that the shock wave propagates over the microchannel with the greatest velocity in the case of the rounded entrance geometry.