低频压力振荡环境下静止液滴蒸发过程的准稳态模型

A quasi-steady model of immobile droplet evaporation with pressure oscillation

关键词:  压力振荡  液滴蒸发  准稳态  动态响应

Key words:  Pressure oscillation  Droplet evaporation  Quasi-steady  Dynamic response

摘要:

为了获得燃料液滴对压力变化得到响应特性,从微观上对压力振荡环境下的液滴蒸发过程进行了分析。结果表明压力振荡会导致流场内部力的不平衡,从而会使液滴周围边界层内气体产生周期性流动,以及液滴周围边界层内蒸气质量分数的振荡,最终会使液滴蒸发速率的产生与压力振荡周期相同的振荡。在此基础上,根据流动边界层理论,提出了饱和蒸气边界层的概念,建立了压力振荡环境下静止液滴蒸发的准稳态模型并进行了数值求解,获得了静止液滴蒸发速率对压力振荡的响应特性。

Abstract:

To obtain dynamic response characteristics of droplet evaporation to pressure oscillation,analysis is implemented for droplet evaporation under condition with pressure oscillation in a view of the microcosmic level.The results show that the pressure oscillation within the flow field can lead to imbalance in force,thus the boundary layer around droplet has a cyclical gas flow,as well as the oscillation of vapor mass fraction,which ultimately brings the oscillation of droplet evaporation rate as the oscillation period of pressure.On the basis of the analysis,a concept of saturated vapor boundary layer is proposed according to the flow boundary layer theory.A quasi-steady model of resting droplet evaporation with pressure oscillation is constructed,and then solved numerically.The dynamic response characteristics of resting droplet evaporation to pressure oscillation are obtained.