薄膜区传热传质蒸发对毛细蒸发弯月面稳定性的影响

摘要

The stability of heated and evaporating capillary meniscus is crucially important for the operation of capillary pumped heat transfer devices.Since more than 50％ of the mass transfer by evaporation occurs on a very small region,so-called thin film region,it is expected that the instability will arise from this region.To explain the stability mechanism of the meniscus effectively,a new method that can skillfully combine the linear stability analysis with the numerical analysis of the meniscus is proposed in this paper.Numerical analysis is executed to acquire the characteristic thickness and length of thin film region,and a linear stability criteria is calculated by using these two characteristic dimensions.By use of the combination of these two analysis methods,the stability mechanism of an evaporating meniscus can be clearly disclosed,especially about the effect of the temperature of the meniscus,thermophysical properties of the working fluid and the dimensions of the capillary tube on the stability.The effectiveness of this method can be approved by the experimental results of some published references.%蒸发毛细弯液面的稳定性对两相传热装置的运行有着重要意义.由于弯液面的蒸发50％以上发生在一个微小区域,即延展薄膜区,可以预期不稳定性将最先产生于这一区域.为对蒸发弯月面的稳定特性进行机理性研究,首次提出一种将线性稳定性分析与薄膜区传热传质数值分析巧妙结合的研究方法.该方法通过传热传质数值分析获得能够反映弯月面稳定特性的特征膜厚和长度,并将其应用于线性稳定性判据以获得弯月面的临界过热度.分析表明,两种方法的结合可以有效揭示蒸发弯月面的稳定机制,特别是毛细管半径、弯液面温度和工质的热物性对弯月面稳定性的影响.与相关文献报道的实验结果比较,证实了该方法的有效性.