Chapter 15.4 - Shock Wave Propagation in Multi-Phase Media: 15.4 Shock Wave Interaction with Liquid Gas Suspensions

Abstract

This chapter deals with the explanation of shock wave interaction with liquid gas suspensions. A typical property of the description of shock waves in gas liquid suspensions is that the thermodynamics of phase transition and of phase equilibrium comes into play. As a consequence the equilibrium sound speed even in a dilute mixture of water and carrier gas jumps at the point where the droplets fully vaporize and disappear. This jump is even more pronounced for wet steam. Since the ratio of frozen and equilibrium sound speeds for water-gas mixtures and for wet steam is of the order of 1.1, it means that weak compressional waves become fully dispersed shock waves. For wet steam, an analytical description of these fully dispersed waves is possible. Partly dispersed shock waves in a dilute mixture of water droplets in a humid carrier gas, such as air or nitrogen, even have a larger thickness, since the evaporation process is delayed by diffusion. In that case, a discontinuous shock front is followed by a relaxation zone. Furthermore, a theoretical model based on the so-called wet-bulb approximation appears to give an accurate description of shock structure.