The Thermodynamic and Fluid Dynamic Functions of a Pulsed Detonation Engine Nozzle

The design and analysis of a Pulsed Detonation Engine, PDE, nozzle creates new and unique technical challenges. These challenges involve both the thermodynamic and the fluid dynamic functions that the PDE nozzle serves. Thermodynamically, the nozzle controls the detonation chamber pressure and converts the hot chamber flow into thrust. Fluid dynamically, the PDE nozzle controls the engine's operating frequency. The contraction ratio of the PDE nozzle is designed to maintain pre-detonation chamber pressure and to control engine operating frequency. In practice, the functions of chamber pressure control and frequency control are synergistic. The expansion ratio of the PDE nozzle is a compromise, which covers the broad nozzle pressure ratio ranges imposed by the dynamic operation of the PDE, as well as the typical Mach number influence. This paper explains these functions and suggests analysis techniques.