热辐射与对流耦合作用下雾滴的运动与蒸发特性

在假设雾滴为单液滴球形的基础上,通过建立雾滴的运动与蒸发模型,对热辐射与对流耦合作用下的雾滴运动与蒸发特性进行了研究。研究发现,室外环境条件对雾滴寿命的主要影响因素是环境湿度和雾滴的初始粒径,而辐射和强迫对流的影响基本可以忽略。热辐射会造成雾滴的温度升高,甚至使雾滴的温度高于环境温度。雾滴的温度会呈现先增后降的变化规律。强迫对流对雾滴温度的影响可以忽略。较大的雾滴初始粒径有利于形成弥散雾,但粒径过大会因为自由沉降而缩短寿命,因此存在最佳的初始粒径。

Motion and Evaporation Characteristics of Spray Droplets Under Coupled Effect of Thermal Radiation and Convection

On the assumption of single spherical frog droplets, the motion and evaporation characteristics of frog droplets under the coupled effect of thermal radiation and forced convection are studied by establishing a model for the motion and evaporation of frog droplets. It is found that the main factors which have influences on the frog droplet lifetime in outdoor environment are ambient humidity and the initial diameter of frog droplets. The influences of thermal radiation and forced convection are negligible. The thermal radiation can cause the temperature of frog droplets to increase, even above the ambient temperature. The temperature of frog droplets may firstly increase and then decrease. The influence of forced convection on the temperature of frog droplets is negligible. The larger initial frog droplet diameter is helpful to the formation of dense frog. However, the oversize diameter may cause the lifetime of frog droplets to decrease due to their sedimentation. So there exists an optimum initial diameter for frog droplets.