Detonation studies of JP-10 with oxygen and air for pulse detonation engine development

Abstract

Detonation studies have been performed at the Naval Postgraduate School in order to investigate the detonation properties of JP-IO aerosol with oxygen and air. Early investigations involved the studies of ethylene and air detonations to evaluate and qualify the facility. These tests proved to be satisfactory and led to the modification of the facility to study the detonation properties for liquid JP- IO and air/oxygen. A clear acrylic model of the combustor was used to assist in quantifying the fuel injection characteristics. Atomization characteristics such as Sauter Mean Diameter and droplet diameter distributions were obtained for various atomization systems. A modular constant-diameter combustor geometry was evaluated in this study. Combilstor length, ignition location, and ignition delay was varied to investigate fully developed detonations as well as the transition characteristics. The effects of wall temperature and fuel injection properties were also investigated. The combustors were operated in a multi-cycle mode at frequencies up to 5 Hz . Detonation wave velocity, strength, and approximate transition lengths were obtain for various test conditions. It was observed that the ignition delay time was a critical parameter for obtaining a rapid transition to a detonation for a cold aerosol spray condition with JPIO/oxygen. The dependence on ignition delay time was seen to diminish as the combustor wall temperature increased. Fully developed detonations for JP 10 and air were not observed with the current system.