摘要
分别采用表面吸收与内部均匀吸收两种辐射模型结合液滴内部有限导热系数模型,数值研究了辐射-对流热环境中正十二烷液滴的蒸发特性.考虑了液滴与周围气流热物性以及液滴/气流相对速度的瞬态变化,获得了不同对流换热条件与辐射源温度下,液滴半径、温度及蒸发率的变化规律.比较了两种辐射吸收模型的预测结果差别,分析了热辐射对液滴蒸发的影响.结果表明,两种辐射吸收模型对液滴寿命预测结果的差别较小,但内部吸收模型能反映液滴表面的能量供给特点.当辐射源温度与对流气流温度相同时,热辐射对液滴蒸发的影响较小;当辐射源温度比对流气流温度高得多时,热辐射的影响很大.
For a single dodecane droplet in the thermal environment of combined convec tion and radiation, the evaporation characteristics were investigated numerically. The internal absorption model of thermal radiation and the surface absorption one was separately combined with the limited conductivity model of droplet. The transient dependence of thermal properties on temperature and components was taken into account along with the transient relative velocity of gas flow to the droplet. The evolvements of droplet radius, temperature and evaporating rate under various convective conditions and various temperatures of thermal radiation were presented. The differences between the predicted results by the two thermal radiation models were compared, and the effect of thermal radiation on droplet evaporation was analyzed. The results show that, the predicted values of droplet lifetime by the two thermal radiation models are relatively less different. But the internal absorption model can reveal the characteristics of energy supply to droplet surface. The effect of thermal radiation on the droplet evaporation is small when the temperature of thermal radiation equals to that of the gas flow, but it becomes very significant at a temperature higher than that of gas flow.
出处
《航空动力学报》
EI
CAS
CSCD
北大核心
2008年第11期2043-2048,共6页
Journal of Aerospace Power
基金
国家自然科学基金(50776026)
关键词
液滴蒸发
正十二烷
热辐射
对流换热
有限导热
droplet evaporation
dodecane
thermal radiation
convective heat transfer
limited conduction
