Optimizing the performance of a hypersonic airbreathing propulsion system.

摘要

Routine access to space is critically dependent on the vehicle system performance and safety. In view of the enormous magnitude of energy required to accelerate a vehicle to orbital velocity, there is an imperative need for utilizing all of the energy available in the system with the highest possible effectiveness. One of the highly advantageous possibilities in the evolution of hypersonic vehicles is to make use of atmospheric air over as much of the mission trajectory as possible. A unique airbreathing concept is presented that employs a steam/water generation system to improve propulsion efficiency, vehicle flight performance and safety. This concept, referred to as a "Propellant Utilization System," is an integral part of the main propulsion system for manned space mission applications. An important element of this research is the performance optimization of a fully reusable, earth-to-orbit vehicle with horizontal takeoff and landing capability. The approach consists of a multi-facet, aero-thermodynamic analysis that addresses (a) energy conversion, (b) mass, momentum and energy recovery, (c) gas separation and liquefaction and (d) cryogenic liquid/fluid storage devices.; The research objective is to develop an analytical representation of a cryogenic reactor system that utilizes onboard H{dollar}sb2{dollar} fuel and engine inlet air as reactants. The products of combustion (steam and water) are stored onboard during flight to provide several attractive advantages. Water is available as a coolant to relieve hypersonic aerodynamic heating loads around the vehicle stagnation point and along the wing leading edge surfaces. Steam is available to provide auxiliary thrust for vehicle orbit insertion, on-orbit maneuvering, de-orbiting and landing. A key task is to establish a procedure for selection of design options and the control variables of a set of candidate parameters that are optimized as part of the fully integrated vehicle.; A complete mission analysis is undertaken utilizing a reference vehicle for comparison purposes. The analysis includes the selection and optimization of system parameters to maximize engine performance in conjunction with flight trajectories that minimize propellant expenditure.