Thermodynamics of Airbreathing Pulse-Detonation Engines

Abstract

An analytical investigation was conducted of the idealized performance potential, from a thermodynamic cycle viewpoint, of airbreathing pulse-detonation engines (PDEs) primarily intended for air-vehicle propulsion. The investigation was restricted to the static operation of PDEs. The detonation-wave model used was of the classical Zel'dovich-von Neumann-Doering type, in which an initiating shock wave is followed by a Rayleigh-type combustion process in a duct, the detonation tube, of uniform cross-sectional area. The results of the analysis indicated that the idealized PDE performance was only slightly better than that of a simple, easily analyzed, constant-volume combustion, Lenoir-type surrogate cycle. The PDE also had the potential of being slightly more efficient, under idealized flight conditions, with induction ramming occurring, than the corresponding surrogate cycle. The corresponding surrogate cycle will advance thermodynamically, due to intake ramming, from a relatively inefficient Lenoir cycle to a more efficient Humphrey, or Atkinson, cycle.