Numerical modeling of valveless airbreathing pulse detonation engine

This paper deals with the modeling and simulation of the internal flowfield in a valveless airbreathing pulse detonation engine (PDE) currently under experimental development at the U.S. Naval Postgraduate School. The system involves no valves in the air-flow path, and the isolation between the inlet and combustor is achieved through the gasdynamics in an isolator. The analysis accommodates the full conservation equations in axisymmetric coordinates, and employs a chemical reaction scheme with a single progress variable calibrated for ethylene/oxygen/air mixtures. The entire flow dynamics and multicycle operation of the engine are carefully investigated. Results indicate that the filling strategy must be carefully defined and optimized to ensure successful transmission of the detonation wave from the initiator to the main chamber and subsequent detonation initiation and propagation. Interactions between the inlet and the combustor should also be treated prudently to avoid engine unstart due to the inlet overpressurization caused by the combustion wave in the main chamber.