摘要
为深入了解液滴蒸发过程中热环境与压力耦合效应的影响,建立考虑液滴与环境气流物性瞬态变化的物理数学模型描述球形燃料液滴的对流蒸发过程.以正庚烷液滴在氮气流中的蒸发为例,数值模拟研究了液滴膨胀与环境压力的影响.结果表明：不考虑液滴膨胀所预测的液滴寿命明显偏长;而环境压力的影响与环境温度、气流相对速度相关;在一定的热环境参数下,压力效应发生逆转;对正庚烷液滴蒸发,在较大的气流相对速度范围内,提高压力可促进液滴蒸发的环境温度下限为680-800K.本研究为燃料液滴蒸发的预测分析奠定了理论基础.
For an in-depth understanding of the coupled effects of thermal environment and pressure on droplet evaporation, the physical and mathematical models describing the convective evaporation of a single spherical fuel droplet are developed, in which the variable physical properties of droplet and ambient gas are taken into account. The evaporating process of a single n-heptane droplet in the nitrogen gas flow was numerically modeled to reveal the effects of droplet expansion and ambient pressure on the evaporation. The results show that ignoring the thermal expansion leads to an over prediction of the evaporation time, and the effect of ambient pressure depends on the temperature and relative velocity of the ambient gas flow. The pressure effect changes backward at certain parameters of thermal environment. For the evaporation of a n-heptane droplet and within a relatively large range of the relative velocity of gas flow, the transition temperature limit is between 680 - 800 K, above which the increase of ambient pressure can accelerate the droplet evaporation. Thus the developed models provide a theoretical basis for analyzing the evaporation of fuel droplets.
出处
《哈尔滨工业大学学报》
EI
CAS
CSCD
北大核心
2008年第1期131-135,共5页
Journal of Harbin Institute of Technology
基金
国家自然科学基金资助项目(50476029
50776026)
关键词
液滴
对流蒸发
环境压力
液滴膨胀
正庚烷
droplet
convective evaporation
ambient pressure
droplet expansion
n - heptane
