Evaporation of Sprays of Liquid Fuels and Liquid Oxidizers in a Shear Layer

Abstract

In rocket engines propelled by liquid fuels and liquid oxidizers, one may e nd regions where two adjacent spray streams,onethatcarriesfueldropletsandtheotherthatcarriesthedropletsoftheliquidoxidizer,travelatdifferent velocities and form a shear e ow. A theoretical study of such unidirectional multisize (polydisperse ) evaporating spray streams is presented. In each of the streams droplets of different sizes are assumed to travel at different longitudinal velocities, that is, drop-size correlated velocities are assumed for both the liquid fuel and the liquid oxidizer. The lateral evolution in drop-size distributions across the shear layer is analyzed, and its effect on the lateral spread of the fuel vapor and the vapors produced by the droplets of the liquid oxidizer is examined. It is shown that the polydisperse drop-size distributions of the liquid fuel as well as that of the liquid oxidizer control the vapor production rates and determine the shape of the vapor concentration proe les across the shear layer.