The Thermodynamic Performance of Ideal Single-Tube Air-Breathing Pulse Detonation Engine

Abstract

A new single-tube air-breathing pulse detonation engine (APDE) with bypass air duct is introduced. It is composed of inlet, valve, detonation chamber, bypass air duct and nozzle. Based on the analysis of the operation cycle of the APDE, airstreams flowing into the engine can be separated into three parts: one is flowing out from the engine through the bypass; one is exhausted from the nozzle as purge gas; and the else is mixed with fuel and is combusted. And the concept of cycle factor α that represents the ratio of air quantity for detonation combustion to incoming air quantity is defined to analyze the influence of the mass distribution on the performance of APDE. Although α has no effect on the cycle thermal efficiency of APDE, it influences the engine propulsive performance. When the APDE is full fuel filled and with the equivalent incoming air-flow and fuel-flow rate, the APDE will be superior to ramjet for 0∼5 Mach if α is larger than 0.8. When the APDE and ramjet work with equal mass fuel-air ratio of combustion, the specific fuel consumption of APDE is lower than that of ramjet for 0∼5 Mach. Also, if a is higher than 0.9, the specific thrust of APDE is higher than ramjet for 0∼5 Mach. Further, the operation mode of partial fuel filling can be used to enhance the performance, but it simultaneously decreases the total thermal cycle efficiency.