高温气流中单个雾滴运动与蒸发的耦合特性

Coupling characteristics of droplet's motion and evaporation in high-temperature gas stream and their influencing factors

针对单个雾滴在高温气流内的运动与蒸发,建立了耦合数学模型,验证了数学模型与计算程序的有效性,对雾滴在高温气流内的运动与蒸发及其影响因素进行了数值分析.结果表明,雾滴在高温气流内的运动与蒸发过程可分为3个阶段,即瞬态升温阶段、饱和蒸发阶段和稳定蒸发阶段;雾滴直径、雾滴初始速度、气流温度及气流速度对雾滴的运动与蒸发都有不同程度的影响,提高雾滴初始速度不能明显提高雾滴蒸发速度,减小雾滴直径是提高雾滴蒸发速度的有效措施;雾滴在不同温度气流中的换热方式有所不同.

For the motion and evaporation of droplet in high-temperature gas stream, the coupling mathematical model was developed. The mathematical model and the computation program were verified. The coupling characteristics of the motion and evaporation of droplet in high-temperature gas flow and their influencing factors were studied numerically. Results indicate that the droplet＇s motion and evaporation in gas flow can be divided into three processes： transient heating process, saturated evaporating process and steady evaporating process. The droplet size, droplet initial velocity, gas temperature and gas velocity affect the droplet＇s motion and evaporation in different way. The droplet＇s evaporation rate can not be increased by increasing its initial velocity, but can be increased by decreasing its size. The heat transfer mode between the droplet and the gas flow is different when the temperature of gas flow is different.