Evaporation and Movement Characteristics of Single Liquid Nitrogen Droplet in High-Speed Gas Flow

An evaporation model of single moving liquid nitrogen droplet in high-speed gas flow is developed based on the classical evaporation model to reveal the evaporation of whole liquid nitrogen spray. The droplet evaporation rate, diameter and velocity are obtained in the evaporation process by adjusting ambient temperature, ambient pressure and gas flow velocity. The results show that for those parameters, the ambient temperature has greater influence on the droplet evaporation rate, which grows with temperature. Within the falling distance of two meters, with the ambient temperature riseing by every 100 K in the range from 100 to 300 K, the relative evaporation increases about 18%. The higher the gas flow speed reaches, the higher the droplet evaporation rate gets at equal time due to the stronger convection heat transfer, but the evaporation capacity decreases because of limited evaporation distance. Under above conditions, the relative evaporation is 5%~6% within the flow speed range of 10~30 m/s. Bigger droplet has bigger absolute evaporation capacity but smaller relative evaporation capacity, and the droplet evaporation rate rises with the ambient pressure.