存在垂直加热时的矩形池内热毛细对流的数值模拟

Numerical simulation of thermocapillary convection in a rectangular cavity with vertical heat transfer

为了了解垂直加热对矩形浅液池内稳态热毛细对流的影响,利用有限容积法进行了二维直接数值模拟,液池左、右壁分别维持恒定温度Th和Tc,且Th〉Tc,底部被加热,自由表面存在散热,液池宽深比为（20-30）,流体为1cSt硅油。结果表明,随着底部加热热流密度的增大,矩形液池内的流动会由单胞或多胞流动转化为旋转方向相反的非对称双胞流动,流动转化过程的临界热流密度随Marangoni数和Biot数的增加而增大,随液池宽深比的增加而减小,液池内的最高温度会随Marangoni数和宽深比的增大而减小。

In order to understand the influence of vertical heat transfer on the thermocapillary flow of 1cSt silicon oil in a rectangular cavity with an adjustable aspect ratio Γ=20~30,a series of numerical simulations were carried out using the finite volume method.The left and right walls of the cavity were maintained constant temperatures Th and Tc（ThTc）,respectively.The bottom of the cavity was heated while the heat loss was considered on the free surface.It is found that the flow pattern transition occurs from the single-roll or multi-roll flow to an asymmetrical double-roll flow with opposition rotation direction with increasing vertical heat transfer rate.The critical heat flux value of flow pattern transition increases with the increase of Marangoni number and Biot number,but it decreases with the increase of the aspect ratio.Moreover,the highest temperature in the cavity decreases when the Marangoni number and the aspect ratio increase.