Analysis of Hypersonic Rarefied Reactive Flow Over RAM-C II Forebody Using hy2Foam Solver

Abstract

The re-entry of space vehicle to the rarefied atmosphere at hypervelocity results in formation of a strong bow shock in front of the vehicle. This causes a sudden rise in gas temperatures, excitation in the different energy modes of the gas molecules, and the onset of various chemical reactions. In this paper, numerical simulations on the hypersonic rarefied reactive flow over the nose cap region of the RAM-C II forebody have been proposed. For the simulations, hy2Foam - an open-source hybrid CFD-DSMC code has been used. We considered dissociation, exchange, and recombination types of chemical reactions with five species, N2, O2, NO, N, and O. The hy2Foam results have been validated with the literature. Further, the solver has been used to study the effects of variation of Mach number and Knudsen number on non-equilibrium hypersonic flows. The maximum fluid temperature increased with an increase in Mach number and decrease in Knudsen number. Also, the maximum wall temperature and wall heat flux increase with an increase in Mach number; however, the maximum wall temperature increases, and the wall heat flux decreases with an increase in Knudsen number.