Numerical simulation of the evaporation characteristics of a dimethyl ether droplet in supercritical environment
Numerical simulation of the evaporation characteristics of a dimethyl ether droplet in supercritical environment
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DOI：
10.1016/j.fuel.2020.117120
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发表时间：
2020-05
期刊：
影响因子：
7.4
通讯作者：
Xu He;Haitao Feng;Zechang Liu;Hongnan Wang;Xiongwei Li;Fanming Zeng;Fengshan Liu;Fushui Liu
中科院分区：
文献类型：
--
作者：
Xu He;Haitao Feng;Zechang Liu;Hongnan Wang;Xiongwei Li;Fanming Zeng;Fengshan Liu;Fushui Liu
在考虑真实的气体效应、Soret和Dufour效应、变物性效应和高压汽液相平衡的基础上，建立了二甲醚液滴在超临界条件下的非稳态球对称蒸发模型。当达到二甲醚-氮气体系的临界温度时，液滴与环境的界面消失。随后，蒸发变成纯扩散问题。计算结果表明，在超临界条件下，环境气体在液相中的溶解度是显著的，界面温度、比化液滴直径和二甲醚摩尔分数在超临界条件下也随时间变化。系统地研究了临界点以上环境压力和温度对液滴蒸发特性的影响。超临界环境导致液滴的初始膨胀较大，当环境压力为2.0，温度为1.5时，液滴的最大膨胀比初始值大7.7%。当环境温度为1.5 ℃，压力在1.0 ~ 1.5之间变化时，二甲醚液滴的蒸发寿命缩短了11.1%.环境温度以与环境压力类似的方式影响液滴蒸发特性。
The unsteady spherically symmetrical evaporation of a dimethyl ether droplet in supercritical environment is modelled, considering real gas effects, Soret and Dufour effect, variable thermodynamic properties effects and high- pressure vapor-liquid phase equilibrium. The interface between droplet and environment disappears when it reaches the critical temperature of dimethyl ether-nitrogen system. Subsequently, the evaporation becomes a pure diffusion issue. The calculated results indicate the solubility of the ambient gas in the liquid phase is significant under supercritical conditions, and the temporal evolution of the interface temperature, reduced droplet diameter and dimethyl ether mole fraction are obtained under supercritical conditions as well. The influence of ambient pressure and temperature above critical point on the droplet evaporation characteristics was systematically investigated. Supercritical environment leads to a larger initial swelling of the droplet, when the reduced ambient pressure is 2.0 and temperature is 1.5, the maximum swelling of droplet is 7.7% larger than the initial value. Higher ambient pressure also leads a shorter fuel droplet lifetime in supercritical environment, When the reduced ambient temperature is 1.5, and the reduced pressure is varying from 1.0 to 1.5, the droplet evaporation lifetime of the dimethyl ether is reduced by 11.1%. The ambient temperature affects the droplet evaporation characteristics in a similar manner as the ambient pressure.