Compressible, Turbulent Flow with Boundary-Layer Heat Addition

Abstract

One proposed method of achieving a reduction in viscous drag or skin friction in scramjet combustors is through hydrogen combustion in the boundary layer. Previous experimental work performed at the University of Queensland indicated that drag reductions of 80% were possible. This paper studies the effects of heat release on supersonic boundary layers at conditions typically found within the combustor duct of a scramjet using a three-dimensional turbulent compressible flow solver with a finite volume formulation for the solution of the compressible Navier-Stokes equations. Large-Eddy Simulation (LES) using the approximate deconvolution model includes the effects of turbulence. Three conditions of a supersonic, perfect gas, flat-plate boundary layers are studied. The first condition is a validation case at Mach 2.88 with a Reynolds number of 2 × 10 (based on incoming boundary layer thickness, Re). The next two cases are Mach 4.42 and 4.21 flows with Reynolds number (Re) of 8.4 × 10 and 6.3 × 10 respectively. The results obtained for all three cases compare very well with experimental and theoretical data and give insight into the changes in turbulent kinetic energy and stress profiles that occur in the processes of drag reduction via heat addition.