Unsteady shock interaction mechanisms of high enthalpy reacting flows over double wedges at Mach 7

Abstract

A recently developed and validated open-source nonequilibrium Navier–Stokes solver, hyperReactingFoam is used for analyses of Mach 7 flows of air with 8.0 megajoules per kilogram (MJ/kg) stagnation enthalpy over double wedges with four distinct aft angles of 45°, 50°, 55°, and 60°. The validation studies contain both qualitative and quantitative comparisons of the obtained results with experimental and two numerical results available in the literature for the 30°–55° double wedge model. Physics and characteristics of the flows are revealed by comparing the shock structures, chemical compositions, surface pressure, and wall heat flux distributions of each aft angle. It is seen that increased aft angle significantly enhances the magnitudes of wall heat flux and surface pressure. Fluctuations of wall heat flux and surface pressure distributions in time significantly increase along the second wedge surface in the case of higher aft angles. Faster chemical reaction rates take place also for larger aft angles, regardless of the assumption of the flow to be in thermal equilibrium or nonequilibrium. The flow is observed to be chemically frozen downstream of the expansion corner. Time-averaged wall heat flux magnitudes of the flow for the aft angle values of 55° and 60° are found to be three times larger than of the flow with 2.1 MJ/kg stagnation enthalpy.