Effect of Surface Evaporation on Steady Thermocapillary Convection in an Annular Pool
Effect of Surface Evaporation on Steady Thermocapillary Convection in an Annular Pool
复制标题
DOI：
10.1007/s12217-016-9510-0
复制
发表时间：
2016-07
影响因子：
1.8
通讯作者：
Li Zhang;Yourong Li;Chun-Mei Wu
中科院分区：
文献类型：
--
作者：
Li Zhang;Yourong Li;Chun-Mei Wu
为了了解环形池内表面蒸发对热毛细对流的影响，对普朗特数为0.01 ~ 50的流体在纯蒸汽环境中的热毛细对流进行了一系列数值模拟。结果表明，热毛细对流总是与自由表面的蒸发过程耦合。随着蒸发毕奥数的增加，表面温度降低，热壁附近的蒸发质量通量明显增加。而在冷壁附近，蒸发质量通量先增大后减小。当Marangoni数较小时，自由表面总蒸发质量速率随蒸发毕奥数的增大而增大;当Marangoni数较大时，总蒸发质量速率先增大后趋于恒定值。环形池的长宽比对热毛细对流强度和总蒸发质量速率有积极的影响。随着普朗特数的增加，表面温度逐渐升高，蒸发质量通量增大，热毛细对流单体逐渐向外壁和自由表面移动。这种影响随着蒸发毕奥数的增加而减小。当蒸发毕奥数较小时，总蒸发质量速率随普朗特数的增加而增加;当毕奥数较大时，普朗特数对总蒸发质量速率的影响很小。
In order to understand the effect of surface evaporation on thermocapillary convection in an annular pool, a series of numerical simulation on thermocapillary convection of the fluids with Prandtl number from 0.01 to 50 in the pure vapor environment were carried out. The results show that thermocapillary convection is always coupled with the evaporation process on the free surface. With the increase of evaporation Biot number, the surface temperature decreases, and the evaporation mass flux near the hot wall increases obviously. However, near the cold wall, the evaporation mass flux increases first, and then decreases. When Marangoni number is small, the total evaporation mass rate at free surface increases with the increase of evaporation Biot number; when Marangoni number is larger, it increases first and then approaches a constant value. The aspect ratio of the annular pool has a positive influence on the thermocapillary convection strength and the total evaporation mass rate. With the increase of Prandtl number, the surface temperature rises gradually and the evaporative mass flux increases, and the thermocapillary convection cell moves gradually toward the outer wall and the free surface. This effect decreases with the increase of evaporation Biot number When evaporation Biot number is smaller, the total evaporation mass rate increases with the Prandtl number; when Biot number is larger, Prandtl number has little impact on the total evaporation mass rate.