Journal of Crystal Growth, Vol.514, 21-28, 2019
Effect of surface heat dissipation on thermocapillary convection of moderate Prandtl number fluid in a shallow annular pool
This paper presents a series of three-dimensional numerical simulations on the effect of surface heat dissipation on thermocapillary convection of moderate Prandtl number fluid in a shallow annular pool. The annular pool with a fixed aspect ratio of 0.05 and radius ratio of 0.5 is filled with 0.65 cSt silicone oil. Its Prandtl number is 6.7. Biot number of surface heat dissipation ranges from 0 to 50. The results show that when Marangoni number is small, thermocapillary convection is the axisymmetric steady flow. When Marangoni number exceeds the critical value, the basic flow will destabilize and transit to the hydrothermal waves that propagate along the clockwise or anticlockwise direction. The critical Marangoni number of the flow destabilization increases with the increase of Biot number. Furthermore, when Biot number increases, the radial temperature gradient on the free surface decreases near the inner cylindrical wall, but increases near the outer cylindrical wall, which results in the thermocapillary convective cell moving gradually from the inner to the outer cylindrical walls. After the flow destabilizes, the temperature fluctuation on the free surface mainly appears near the outer cylinder at a large Biot number.