Investigation of Pulse Detonation Engines: the Effect of Variable Blockage Ratio on the Deflagration to Detonation Transition

Detonation and constant volume combustion is well known to be thermodynamically more efficient than the typically utilized constant pressure. There have been numerous approaches of achieving detonation through deflagration-to-detonation transition most of which use evenly spaced obstacles with a specified constant blockage ratio to generate turbulence and pressure fluctuations. There have been few efforts to study effects of varying blockage ratio as a function of axial distance. This research analyzes the effect of variable blockage ratio on deflagration-to-detonation transition in ethylene-air mixtures. The experiments show that with certain blockage ratio functions detonation is more repeatable and produces a smaller variation in both peak pressure and wave velocity representative of consistently stable detonations