切应力协同下受热过冷层流液膜的破断特性

摘要

针对界面切应力协同下受热过冷层流液膜流动的破断过程,建立了不同气液流向下的临界液膜厚度和最小润湿量的理论模型,分析了不同驱动力作用下,接触角、流体温度、界面切应力和壁面热流密度对液膜破断特性的影响.研究表明:临界液膜厚度和最小润湿量均随壁面热流密度的增加而增大;重力驱动下的接触角影响在不同热流密度下有所不同,流体温度在不同驱动力下对最小润湿鼍的影响截然相反;同向切应力驱动下临界液膜厚度和最小润湿量随切应力增加而减小;在重力和切应力协同驱动下,同向切应力对最小润湿量的影响与重力和切应力所起作用的相对大小有关,反向切应力使得临界液膜厚度和最小润湿量有所增大.%The theoretical models of critical film thickness and minimum wetting rate were established for locally heated and subcooled laminar films under different flow directions of gas and liquid, and the effects of the contact angle, film temperature, interracial shear and heat flux were discussed driving by gravity or/and interracial shear. The investigation shows that the critical film thickness and minimum wetting rate increase with increasing heat flux. The effect of contact angle is clearly different in different range of heat flux under gravity driving, and the film temperature has a contrary influence on minimum wetting rate driving by gravity and interracial shear. The critical film thickness and minimum wetting rate decrease with cocurrent shear.Under the combination of gravity and interracial shear, the effect of cocurrent shear on minimum wetting rate is closely related with the ratio of gravity to shear, and the increasing countercurrent shear leads the critical film thickness and minimum wetting rate to decrease.