Design of a Pulse-Facility Nozzle Using the Rotational Method of Characteristics

摘要

A new nozzle has been designed for NASA's HYPULSE shock/expansion tube facility to be used for scramjet engine testing at a Mach-15 flight-enthalpy condition. The nozzle has an area ratio of 9.5:1 that expands the inflow from Mach 6 along the centerline to Mach 8.7 and achieves the goal of increasing the area of the core flow (by a factor of 9). The nozzle contour was generated by a new computer program that solves the Euler equations using the rotational method of characteristics. The rotational method was required to properly include the effects of the boundary layer-induced nonuniformities of the flow properties at the nozzle inflow. Although the density and Mach number vary radially at the nozzle exit due to the nonuniformities of the inflow, the new nozzle produces exit flow that is parallel and has uniform static pressure. The design has been verified with a computational fluid dynamics calculation that compares favorably with the method of characteristics solution.