Soret效应对环形浅池内溶液热毛细对流的影响

Influence of Soret Effect on Thermocapillary Convection of a Binary Mixture in a Shallow Annular Pool

采用三维数值模拟方法研究了Soret效应对深宽比为0.1的环形浅液池内双组分溶液热毛细对流的影响。结果表明,当热毛细Reynolds数较小时,溶液流动为二维轴对称稳态流动,相同热毛细Reynolds数下双组分溶液热毛细对流强于纯工质。由于双组分溶液中Soret效应的作用,冷壁面附近溶质浓度大于热壁面附近溶质浓度,且溶质毛细力方向与热毛细力方向一致,因此,溶液流动加强,相比纯工质更易失稳。流动失稳后,双组分溶液中呈现出热流体波与三维振荡流动并存的流动结构,且Soret效应对热流体波波数和主频有明显影响。

A series of three-dimensional numerical simulations were conducted to understand the influence of Soret effect on thermocapillary convection of a binary mixture in a shallow annular pool.When the thermocapillary Reynolds number is small,the flow is stable and axisymmetric.The flow strength in the binary mixture is bigger than that in the pure fluid.Due to the Soret effect of the binary mixture,the concentration of the solute near the inner wall is higher than that near the outer wall.The coupled action of thermocapillary and solutecapillary forces enhances the thermocapillary convection.The flow of binary mixture becomes more instable,and the critical Reynolds number decreases.When the thermocapillary Reynolds number exceeds a critical value,the flow pattern behaves as a coupling of the hydrothermal waves and three-dimensional oscillatory flow.Soret effect has a significant effect on the characteristics of the hydrothermal waves,including the wave number and oscillation frequency.