高温气流中液滴蒸发影响因素的数值研究

Numerical Research on Influencing Factors of Droplet Evaporation in High Temperature Airflow

建立了液滴蒸发的数学模型,利用数值求解方法,模拟计算高温气流中液滴的蒸发过程,得出液滴的蒸发规律。液滴蒸发速率经历一个先增大后减小的过程,气流温度和气流速度都可加速液滴的蒸发,气流温度可使蒸发速率提高100%以上,而气流速度对蒸发速率的提高幅度不足50%;液滴蒸发的平衡温度只受气流温度的影响,而气流速度、液滴初始温度和液滴初始直径只影响液滴达到平衡温度的时间;气液交换热量随蒸发过程的进行逐渐减小,气流温度升高和气流速度增大,气液交换热量的极大值及其变化率增大,但只有液滴初始温度和液滴初始直径影响气液交换的总热量。

A mathematical model for droplet evaporation was esablished and the droplet evaporation process in high temperature airflow was investigated by numerical simulation method. The rule of the droplet evaporation was gained. The rate of the droplet evaporation first increases and then decreases. The airflow temperature and velocity can accelerate the droplet evaporation, by more than 100% and by less than 50% respectively. The equilibrium temperature of the droplet evaporation is only affected by the airflow temperature, while the initial droplet temperature, airflow velocity and initial droplet diameter have an impact on the time when the droplets get to the equilibrium temperature. The gas-liquid exchange heat decreases with the evaporation process. While the airflow temperature and velocity increase, the maximum of the gas-liquid exchange heat and its variation increase. But only the initial droplet temperature and the initial droplet diameter influence the total gas-fluid exchange heat quantity.