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Thermocapillary convection in melt crystal growth process , caused by the surface tension gradient prominent factors affect the quality of the material , therefore , thermocapillary convection in-depth study of the physical mechanisms not only important basic research on fluid physics , industrial production some practical value . Established physical and mathematical models of annular liquid pool thermocapillary convection to the outer wall of the liquid pool is heated , the inner wall is cooled , and the free surface and bottom are adiabatic . The linear stability of the method of analysis of the annular fluid tanks thermocapillary flows of low Pr number fluid into critical condition , namely the critical Marangoni number and the critical wave number , respectively, discussed the gravity and microgravity conditions liquid pool depth aspect ratio , radius ratio , the rotation speed of thermocapillary convection transition conditions , the main conclusions are as follows: (1) for thermocapillary flow annular liquid pool , when the Marangoni number is small , the flow is stationary axisymmetric flow , when the Marangoni number is gradually increasing , more than after a certain value , the flow instability into a three-dimensional oscillating flow , that is, there is a critical Marangoni number ; (2 ) under microgravity conditions , with increasing liquid pool depth aspect ratio , the critical Marangoni number and the critical wave number will gradually decrease when the aspect ratio is greater than 0.12 , the critical wave number substantially constant ; gradually decreases as the radius ratio increases , the critical Marangoni , but reduced the amplitude is not critical wave number there is a large increase ; speed increase the critical Marangoni number will have a slight increase , but the same critical wave number ; (3) under the conditions of gravity , from the critical Marangoni number than under microgravity conditions when the same conditions , is essentially the same critical wave number ; With liquid pool depth to width ratio and the radius ratio increases , the critical Marangoni number will gradually decrease; critical Marangoni number will increase as the speed becomes large .
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