环形液池浮力-热毛细对流表面振荡现象的临界温差

对于上部开口的环形液池,加载径向温度梯度将使气液接触面上表面张力分布不均匀,耦合于地面的重力作用,将会驱动薄层流体形成浮力-热毛细对流。当径向温度差ΔT达到某一临界值ΔTC时,一定厚度的液层表面就会出现具有一定规律的振荡现象。实验采用高精度激光位移传感系统,测量了液池表面某点位移随液层厚度h和径向温差ΔT的变化曲线,讨论了浮力-热毛细对流表面振荡的临界温差及两种驱动力的耦合问题,进行了表面畸变参数的无量纲分析,考虑了起始环境温度对临界温差的影响,推导了振荡相对较强时液层的厚度范围。

Critical temperature difference of surface oscillation of buoyant-thermocapillary convection in an open cylindrical annuli

Thermocapillary convection occurs when a radial temperature difference is subjected to an open cylindrical annuli.It is driven by temperature-induced interfacial-tension variation.Combined with the gravity on the ground,the buoyant-thermocapillary convection becomes more complex.When temperature difference ΔT reaches a critical value ΔTc,regular oscillation appears on the open surface,which changes with the layer thickness h.In our experiments,high-precision sensor system is applied to measure the surface displacements.Critical temperature differences of the oscillations are discussed as well as the coupled driven forces in our study.Surface deformation is analyzed by none-dimensional method and the influence of environmental temperature is also concerned.Additionally,approximate layer thickness range is deduced when strong signals happened.