Unsteady design-point performance modeling of a pulse detonation turbine engine

An unsteady overall performance model for design-point analysis is developed for a pulse detonation turbojet engine to address the strongly unsteady outlet parameters of the pulse detonation combustor (PDC) in pulse detonation turbine engines (PDTEs). The unsteady combustor outlet parameters are obtained from an analytical PDC working-process model, and a finite time-step method is used to quasi-steadily model the unsteady flow in the turbine and nozzle. On this basis, a PDTE design-point performance calculation method is established by incorporating characteristic-map scaling. The model is validated using experimental data from a PDC–turbine test rig, and the predicted turbine power agrees well with the measurements, with a maximum relative error below 9%. The results show that, under the same total pressure ratio, pressure-gain combustion improves the thermodynamic availability of the working gas, enabling the PDTE to retain higher available energy at the turbine exit and greater expansion capability in the nozzle. After integration over the detonation cycle, the average thrust of the PDTE reaches 665.7 N, about 10.5% higher than that of a conventional turbojet engine. Parametric analysis shows that decreases in compressor efficiency, isolator total pressure recovery coefficient, and turbine efficiency reduce thrust and increase specific fuel consumption, whereas increasing turbine inlet temperature and reducing PDC fill fraction improve overall engine performance.