【摘要】 液封厚度对液封系统内的热毛细对流有着重要的影响,但已有的大多数研究集中于单向温差下流体在液封系统中的流动.文中采用数值模拟方法研究了液封厚度对双向温差下环形双液层内热毛细对流的影响.模拟过程中,液池底部施加线性温度梯度,自由表面考虑对流换热,厚度比H_r取0.1~0.9,热毛细雷诺数Re取0~1.5×10~6,液池深宽比Γ取0.1、0.2、0.3.结果表明:Re较小时流动为稳态,热毛细对流强度随H_r增大而减弱;当Re不断增大至超过一定值时,流体的流动转变为振荡的多胞流动,流体振荡振幅和流动强度随H_r增大而减小;流动转变的临界值不随H_r单调变化,H_r=0.5~0.7可以使得不同Γ下的临界Re最大,此时流动稳定性最好.更多还原

【Abstract】 The liquid layer thickness plays an important role in the thermocapillary convection of liquid layer system. However,most of previous researches focused on the convention caused by a mono-directional temperature gradient. In this paper,the effect of the liquid layer thickness on the thermocapillary convection in an annular twolayer system subjected to a bidirectional complex temperature gradient is investigated by a set of two-dimensional numerical simulations. In the simulations,the system bottom is heated by following a linear temperature profile,and the free surface convects with outer space. Moreover,the liquid layer thickness ratio H_r changes from 0. 1 to 0. 9,the range of the radial temperature difference Re is 0 ~ 1. 5 × 10~6,and the thickness radial ratio Γ is 0. 1,0. 2,0. 3. The results show that( 1) when Re is smaller,there exists an axisymmetric steady flow,and the thermocapillary convection decreases with the increase of H_r;( 2) an unsteady multi-cellular flow occurs as Re increases and then exceeds a critical value,and both the amplitude and the convection decrease with the increase of H_r;( 3) the critical value changes with H_r in a non-monotonic way; and( 4) when H_r locates between 0. 5 and 0. 7,the critical Re is always the biggest at different Γ,and the system is in the most stable state.更多还原