Computational modelling of hypersonic propulsion intakes at off-design conditions

Abstract

Hypersonic airbreathing propulsion is soon to become a viable means of transportation and hence determination of engine efficiency at varying flow conditions is important. This report contains the summary of literature surveyed on hypersonic airbreathing propulsion and intake design. An overview of ramjet/scramjets and flow factors that affect their efficiency were studied. A 2D planar intake was studied to generate Mach reflections via a shock-expansion interaction. The Mach reflection geometry was predicted with a slipstream profiler and an algebraic model, which was compared to finite volume based CFD code. An axisymmetric intake with a similar configuration to the planar intake was used to generate shock-expansion interactions. A Method of Characteristics code was written to predict the Von Neumann and Detachment Criteria for the transition between regular and Mach reflections. CFD was used to confirm the existence of a shock reflection transition hysteresis in a traverse of this dual solution domain. An increase in the freestream Mach number and initial flow angle for the planar intakes led to a complex subsonic/supersonic flowfield involving multiple shock reflections and interactions, known as a Type 3 Mach reflection. A temporal analysis was carried out to provide insight into the development of the Type 3 case using CFD. The initial flow angle was increased sequentially to assess the affect on the flowfield topology.