Investigations of cycle processes in a pulsed detonation engine operating on fuel-air mixtures

摘要

Experimental and computational investigations of a pulsed detonation engine (PDE) under cyclic operation, using hydrogen-air and hydrocarbon-air mixtures, are reported. Experimental measurements from a single-tube PDE in cyclic operation include visualizations of deflagration-to-detonation transition (DDT) and blowdown processes, and dynamic pressure measurements. Simulations were performed for two geometry configurations: an ideal tube PDE with a smooth-wall, initially filled with premixed fuel-air mixtures; and a benchmark tube PDE with internal geometry, a valveless air supply, and in situ fuel injection. Comparisons of experimental and computational visualizations in the benchmark tube PDE show good agreement in cycle process time scales. Realistic simulations of all processes of the PDE cycle (fill, DDT, detonation propagation, blowdown, and purge) of a benchmark tube PDE yield important insights into factors influencing performance. Performance metrics of thrust and impulse were estimated by application of a two-step reduced mechanism for fuel-air mixtures (H_2, C_2H_2, C_2H_4, and C_3H_8) and were validated using data from an ideal tube PDE in the literature.