A numerical study on high-temperature effects of exploding shock waves

Abstract

A planar shock of initial strength MS = 3.0 was focused to a tiny region in space using a spherically converging test section. The shock accelerates inside the test section, collides with the focusing end wall, and gets reflected. Numerical studies show that the flow behind reflected shock behaves like an expanding jet moving through a confined area. It was observed that this expansion caused the formation of a mushroom-shaped structure. Thermodynamic characterization of the mushroom structure was made, and it was found that the gas temperature inside the mushroom structure is higher than that across the reflected shock itself. High-temperature effects, such as temperature-dependent Cp variations and dissociation–recombination reactions of the test gas, were added to the simulations to better understand the effect of temperature on the expanding hot gas. A reduction of 39% in the peak temperature value was obtained at the focusing end wall. Also, the flow inside the mushroom structure was observed to be a reactive mixture of a hot gas slug. It is observed that prominent molecular dissociation and recombination take place inside the mushroom structure, which is absent across the reflected shock.