Liquid Hydrocarbon Detonation Branching in a Pulse Detonation Engine

Abstract

Pulse detonation engines operate on a fill-detonate-exhaust cycle with thrust directly proportional to the cycle frequency. That is, a decrease in cycle time results in increased thrust. This paper shows that the detonate portion of the cycle can be shortened by using a branched detonation as the ignition source as opposed to a spark plug type of ignition. The combustion energy from a branched detonation allows ignition and deflagration-todetonation transition to occur more quickly, shortening overall cycle time. Further, while detonation branching has been previously accomplished using gaseous hydrogen fuel, this paper reports the first application of detonation branching using liquid hydrocarbon fuel. For this application, a pressurized heating system was designed to vaporize the fuel and mix it with an airstream to stoichiometric conditions.

Characterization of Shock Wave Transfer in a Pulse Detonation Engine–Crossover System

“…[12][13][14][15] were presented for the L Tube 0.46 m, D Tube 12.7 mm crossover tube cases. The following is a collection of comparisons with the two other diameters (D Tube 18.8 and 26.6 mm) and three other frequencies (f 10, 15, and 20 Hz).…”

“…This transfer tube is referred to as a crossover tube. This detonation transfer concept has been studied thoroughly, and results indicate that it reduces the overall cycle time and increases overall cycle efficiency [10][11][12][13][14]. However, for the detonation transfer process to work properly, the crossover tube must be purged of hot products to prevent autoignition and be refilled with reactants to ensure complete detonation transfer.…”