The criterion on the Propulsive Balance of Oblique Detonation Engine

TL;DR

This paper derives a criterion for the propulsive balance of oblique detonation engines, highlighting the importance of inlet exit temperature and providing calculations for specific impulse across different fuel mixtures and Mach numbers.

Contribution

It introduces a physical model and explicit criterion for propulsive performance of ODEs, emphasizing the role of inlet exit temperature in thrust efficiency.

Findings

Positive net thrust achievable from Mach 8 to 15

Lower inlet exit temperature increases specific impulse

Calculations for H2/air and hydrocarbon/air mixtures

Abstract

The oblique detonation engine (ODE) has established a clear superiority for hypersonic flight because of its high thermal efficiency and compact structure. It has become the research hot spot all over the world in recent years. The aim of this study is to derive a criterion on the propulsive balance of ODE, from which we can find the key parameters governing the propulsive performance explicitly. A physical model of ODE is put forth, which consists of the inlet, the constant cross-section combustor and the divergent nozzle. The mathematical equations to calculate the thrust generated by the divergent nozzle and the pressure drag produced by the inlet are deduced. The net thrust of ODE is then obtained. The criterion shows clearly that the static temperature at the engine inlet exit is a very important parameter. The lower the inlet exit temperature is, the higher the specific impulse will be. The specific impulse of ODE with stoichiometric H2/air mixture and hydrocarbon/air mixture are calculated by using these equations. The results show that ODE can obtain positive net thrust from Ma8 to Ma15.