Multiphase Detonations in Pulse Detonation Engines-A Status Report

Abstract

Motivated by the current interest in pulse detonation engines, a brief review of previous work on multiphase detonations is presented in this paper. The primary focus is on liquid-fuelled detonations in tubes. Theoretical, computational and experimental studies have shown that if the droplets are fine enough (less than about 10 microns), detonations propagating at about the equivalent gas-phase Chapman-Jouguet detonation velocity can be attained in a variety of fueloxygen systems. With larger droplet sizes, a deficit in the propagation velocity when compared to the gas-phase velocity is observed. Various explanations for this deficit are presented. The minimum droplet size required for fuel-air mixtures is not yet clear. Heating the initial mixture helps both by easing the detonation initiation process as well as aiding in the detonation propagation by introducing some prevaporization and reducing the droplet size. The need for additional research on multiphase detonations to aid in the further development of liquid-fuelled pulse detonation engines is also highlighted.