A heat transfer model for aluminum droplet/wall impact

Abstract

The erosive burning in solid rocket motor is partly caused by heat flux increment effect of dense high-temperature droplet jet impact process, of which the basic physical process is single molten droplet impact solid wall. However, due to the complex process in combustion chamber, until now, the erosion mechanism under such conditions has not been scientifically described. In this study, with the combustion chamber condition being simulated, the bouncing process of single molten aluminum droplet/wall impact was obtained experimentally. The theoretical model about droplet contact time as well as the maximum spreading factor were modified based on the experiment data. The theoretical heat transfer model accounting for single aluminum droplet/wall impact process was established, with the assumption of a composite structure consisting of solid material and air cavities on the solid wall surface. The theoretical predicted magnitude order of heat flux between droplet and solid wall surface is approximately 103∼104 W/cm2, and the heat transferred to the wall is approximately 10−6∼10−5 J for single droplet impact.