Experimental Study on Combustion of Monodispersed and Mono-sized Sprays by Using the Fifth TR-IA Rocket

Abstract

A fundamental study on spray combustion was carried out by using microgravity conditions produced by the fifth TR-IA rocket. Very lean methanol-air premixtures were ignited by a hot wire to investigate the behavior of the ignition process of fuel vapor-air mixture which exists in an ethanol spray. Shadowgraphy and shearing interferometry were employed to observe the ignition process. Experiments were performed three times in six minutes of microgravity conditions. Since the amount of fuel charged into a combustion chamber became unknown, quantitative analysis of the experimental data could not be made. However, it was observed that a flame kernel grew spherically up to about 14 mm in diameter in very lean premixtures. These detailed data on the ignition of lean premixtures have never been obtained under normal gravity conditions. From the results of simple numerical calculations, it was suggested that a flame kernel which does not transit to a self-supporting flame is sustained steadily by the mass diffusion and the heat from the heat source.