Performance analysis of a liquid air cycle engine.

Abstract

Cycle structure of a liquid air cycle engine(LACE) for hypersonic aircraft was established and the influence of temperature efficiency of the liquefier, combustion pressure and flight Mach number on fuel ratio thrust was analysed. LACE decelerates, compresses and liquefies air inflowing at high speed. The liquefied hydrogen is pressurized to the combustor pressure and prresurized hydrogen was injected and combusted with pressurized liquid air, and the thrust can be obtained by expansion of combustion gas. Better the temperature efficiency of liquefier, larger the thrust and smaller the equivalence ratio of hydrogen in LACE, independent of flight altitude and speed. When flight altitude and Mach number are given, the combustion pressure to maximize the fuel ratio thrust can be determined. Further, there is the Mach number to maximize the specific thrust. Higher the altitude, larger the specific thrust at the optimal combustion pressure. The Mach number maximizing the specific thrust increases with the increase of the altitude. (9 figs, 2 tabs, 10 refs)