Numerical investigation on the performance of a pulse detonation engine with injected flows

In order to explore an effective way for appropriate design of the pulse detonation engine (PDE) nozzle, oxygen enriched flows have been introduced into the detonation tube near the tube exit to minimize the pressure fluctuations caused by repetitive detonations. A series of numerical studies on the performance with injected flows were carried out. A two-dimentional numerical model including chemical elementary mechanism for hydrogen/oxygen combustion was employed for a single pulse blowdown process in the PDE. The impact of the nonuniform fuel distribution on the thrust and flow features at the tube exit were evaluated at first. Then effects of injector locations and mixture concentrations in injected flows on exit flow conditions and thrusts of PDEs were discussed. It was indicated that not only pressure spikes at the tube exit and the nozzle exit but also thrust spikes decreased when oxygen enriched flows were injected into the tube, and a maximum decrease of 50% was achieved while the injector was 5d away from the tube exit. As to average thrusts of PDEs, less decreases were attained with a least decrease of 3.8%. Mixture concentrations of the injected flows had little impact on neither the pressure at the tube exit, the pressure at the nozzle exit nor the thrust. But the average thrust varied with the fractions of oxygen in injected flows, and it is indicated that mixtures with greater oxygen fractions than 0.7 would increase the propulsive performance.