Simultaneous Observation of Liquid Phase Distribution and Flame Front Evolution during the Ignition Transcient of a LOX/GH2-Combustor

Abstract

Phenomena on millisecond time scale during the transient ignition process in a cryogenic model rocket combustor, like flame propagation, flame/spray interaction, and flame stabilization have not been investigated in detail up to now. Diagnostic techniques developed for characterizing the stationary spray flame are applied to investigate the transient evolution of the LOX-spray and the flame front during the ignition process. Ignition was initiated by focusing a pulsed laser into the combustion chamber. Thus ignition time as well as the position of ignition was well defined. This and the exact control of the delay between ignition and detection time allowed to observe the evolution of the flame front.The distribution of the liquid phase of LOX-droplets have been determined by light-sheet techniques using a double pulsed laser system. Simultaneously the position of the flame front is measured by recordimg the spontaneous emission of the OH-radical. By varying the delay time Pi between ignition and detection in a series of the test runs the transient ignition phenomena have been investigated in the interval from 0 to 5 ms after ignition.