Starting Characteristics of Prandtl–Meyer Scramjet Intakes with Overboard Spillage

Abstract

The method for obtaining the limiting contraction for supersonic intake-starting via overboard spillage demonstrated earlier by Veillard et al. (“Limiting Contractions for Starting Simple Ramp-Type Scramjet Intakes with Overboard Spillage,” Journal of Propulsion and Power, Vol. 24, No. 5, 2008, pp. 1042–1049) is applied in the present paper to Prandtl–Meyer scramjet intakes. Starting characteristics for Prandtl–Meyer intakes of various particular designs are also obtained. It is shown that the strong shock design principle proposed by Veillard et al. for simple ramp-type intakes holds for Prandtl–Meyer intakes as well, that is, the intake design based on the assumption of a strong shock terminating at the trailing edge of the intake’s ramp would lead to the Kantrowitz (self-starting) line, which is very close to the theoretically established limiting values for this intake family. The theoretical findings on startability of Prandtl–Meyer intakes are confirmed by the numerical intake-starting experiments based on the same flow model as the one used in the theory (inviscid non-heat-conducting ideal gas with constant specific heats).