Abstract: Abstract: Single droplet evaporation is one of the important physical processes in liquid spray. Various models were formulated in the literature to compute the mass flow rate of droplet evaporation. It is found that all these models can be written in a single formulation, with various models represented by the different expressions in the driving force HM, which can be classified into three kinds, namely, classical model, mass analogy model and drift-flux model. In this paper, we perform an analysis of the assumptions involved in the derivation of the three kinds of models, and find that the drift-flux model which takes into account the effects of Stefan flow and corrective mass transfer, should be the correct expression, while the classical model ignores Stefan flow effect and the mass analogy model ignores transient effect. Then a study of the influence of the mass driving force HM on the droplet evaporation is carried out, we conclude that both the classical model and the mass analogy model underestimate the effect of evaporation especially at a high evaporate rate.

Key words: liquid spray, droplet evaporation, mass transfer driving force, mass flow rate

摘要： 液滴蒸发是液体喷雾的重要物理过程，文献中使用了不同的模型计算液滴蒸发中的质量流率。依据质量传递驱动力HM的处理，可将这些模型归类于三种不同形式，即经典模型、质量类比模型和漂移流动模型。本文对这些模型的来源和假设作了分析和总结，发现漂移流动模型考虑了Stefan效应和质量迁移，应为正确的表述，而经典模型忽略了瞬态效应，质量类比模型忽略了Stefan流效应。最后以两种不同蒸发率条件下的液滴蒸发为例进行计算，研究了不同质量传递驱动力对液滴蒸发的影响， 发现经典模型和质量类比模型都对液滴的蒸发估计过低，且高蒸发率下三种模型对液滴蒸发特性的影响更显著。

关键词: 液体喷雾, 液滴蒸发, 质量传递驱动力, 质量流率