两元混合物反重力流蒸发传热传质数值研究

The Numerical Research on Heat and Mass Transfer of Anti-Gravity Flow Evaporation of Binary Mixtures

近年来微槽内的液体流动和传热受到了广泛关注,成为新的研究热点。本文在对热润湿作用下水平螺旋管表面反重力流形成及其流动特性进行探索的基础上,建立了适用于水平螺旋槽管壁面二元混合物反重力流蒸发传热传质耦合的物理模型。模拟结果表明,由于液膜内部存在着传质,径向有明显的浓度梯度,从而降低了蒸发传热的温度推动力。酒精溶液的浓度越高,换热系数越小,表明溶液中传质对传热有抑制作用,且其影响不可忽略。

This paper focuses on the heat and mass transfer of anti-gravity flow evaporation of binary mixtures on the surface of microscale fluted horizontal tubes.A physical model based on certain hypothesis is presented to describe the heat and mass transfer performance for rising film evaporation. The simulation results indicate that the temperature driving force to evaporation becomes smaller due to the existence of concentration gradient at the radial direction.The higher the concentration of alcohol is,the smaller the heat transfer coefficient is,indicating that the mass transfer counteracts the heat transfer,which cannot be ignored in the model.