Hypersonic Engine Using MHD Energy Bypass with a Conventional Turbojet

Abstract

This paper reports current progress and results in studies of energy extraction and bypass along the gas path of jet propulsion engines, using magneto -hydro -dynamic (MHD) processes. Specifically, an MHD bypass engine cycl e incorporating conventional gas turbine technology is being explored. It may be a viable approach to both a first stage of a future two -stage -to -orbit vehicle, and to high -speed military/commercial long-range cruise vehicles. The overall research objectiv e is to establish the feasibility and demonstrability of kinetic energy bypass from a weakly ionized inlet air stream of a turbojet. The weak, non -equilibrium ionization is provided by an external electrical means such as an electron beam. MHD interaction with the ionized gas then leads to energy bypass of the turbojet. The resulting wide operating range engine consists of an existing commercial or military jet engine preceded by an MHD power generator. The resulting revolutionary engine would power a vehic le capable of flight from takeoff to Mach 7 during which the turbojet operates continuously over this entire flight regime. The specific MHD inlet design under study is an annular generator/accelerator concept (patent pending). Its embodiment has a superco nducting magnet in a configuration similar to that of a Hall Thruster for space applications. Our research efforts include defining the operating conditions for an MHD bypass turbojet cycle, developing a viscous compressible MHD flow code with real -gas eff ects for flow analysis, air ionization technique assessment, MHD interaction tests, component conceptual design, and a test plan for a generator -turbojet combination in an appropriate wind-tunnel facility.