Droplet Evaporation on a Hot Surface in Pressurized and Heated Ambient Gas

Abstract

An experimental and a theoretical study of the evaporation of a single droplet on a hot surface under the elevated ambient temperature and pressure (0∼50kg/cm²) were made in order to elucidate the evaporation phenomena of spray droplets on the walls in the combustion chambers of diesel engines. In the experimental work, the effects of ambient gas pressure, temperature and initial droplet temperature on the life time of a fuel droplet were investigated. The results show that life time curve shifts to the direction of higher plate temperature and the life time in spheroidal evaporation decreases with an increasing ambient gas pressure. Only the spheroidal evaporation is affected by the ambient gas temperature. In the analysis, different models were postulated for the film evaporation and the spheroidal evaporation, and the differential equations about the temperature and the diameter of a droplet were derived. The theoretical results show reasonable agreement with the experimental results.