Computational study of shock wave propagation and reflection in a micro shock tube

Abstract

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.

Micro shock tubes are miniature devices used for a variety of application in small scale devices likes MEMS equipments. The inherent low flow dimensions combined with low operating pressure makes these devices to behave differently compared to macro shock tubes. In the present study a CFD method was employed to study the shock propagation and reflection inside a micro shock tube. The shock propagation under rarefied conditions due to the low pressure prevailing in the system was studied, in detail. Navier-Stokes equation together with Maxwell’s slip equations were used to simulate the rarefied flow. In these devices, boundary layer effects become a significant parameter in controlling the shock movement and strength owing to its small flow diameter. This paper focuses on giving detail explanation for the disparities in flow physics and its effect on shock movement for micro shock tube under different low pressure and diameter conditions. The results show a greater loss in the shock strength as the diameter or pressure decreases and hence shock waves get attenuated.