Effect of Marangoni number on thermocapillary convection in a liquid bridge under microgravity

Three dimensional numerical simulations are carried out to investigate the effect of Marangoni number (Ma) on the thermo-solutal capillary convection in a liquid bridge under microgravity. Upper and lower disks of the liquid bridge maintain a constant temperature and solute concentration. The computational results show that two rows of interlaced vertical waves form at the center of the r = 0.5 cm ring surface. The number of the interlaced vertical bar waves increases from 10 to 12 with Ma increase from 3.58 × 103 to 5.37 × 103, which inferred the enhancement in strength and instability of thermocapillary convection with Ma. On the θ = 0° plane of the liquid bridge, the low concentration of oxygen displays a 'dumbbell shape' at the center. On the z/L = 0.5 plane of the liquid bridge, the oxygen concentration appears an inhomogeneous 'star shape' distribution. Moreover, the concentration and radial segregation effect of oxygen increase with the increment of Ma in floating zone.