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In the process of crystal growth , the thermocapillary convection caused by the surface tension gradient become important factors that affect the quality of the crystal material . The the liquid seal Czochralski growth technology can effectively suppress thermocapillary convection in the melt , but the growth of technology in very lack of understanding of the basic characteristics of heat convection process annular double - layer liquid system , therefore , to study the role of horizontal temperature gradient ring double- liquid heat convection process stability , to change the physical mechanism of its basic characteristics , has important theoretical significance and practical value for improving the production process , improve product quality . The double annular liquid memory in the horizontal temperature gradient thermal convection process of physical and mathematical models , using the finite volume method , a two-dimensional numerical simulation , based on double the fluid flow and temperature fields distribution analysis of the Marangoni (Ma) number , buoyancy and geometric parameters of the thermal convection , critical Ma number obtained under various conditions , to investigate the flow instability physical mechanism . The results show that : (1) When the Ma number of small , weak flow , the steady-state two-dimensional flow . Ma number and the aspect ratio increases , the intensity of flow enhancement , isotherms strong nonlinear deformation occurred ; the buoyancy introduced to strengthen the flow within the melt layer . Small flow cell (2) the Ma number exceeds a critical value , the flow will lose stability , additional appear near the cold wall , the flow will be converted into non- stable polytope current . The small streams Cellular formed near the cold wall to the hot wall movement, and finally disappeared in the vicinity of the hot wall . Ma number is smaller , the multi - cell structure is mainly concentrated in the vicinity of the cold wall , speed, temperature oscillations only the narrow region near the cold wall , the With Ma and aspect ratio increases , the velocity, temperature oscillation enhancement and extended toward the hot wall , multi- cell area in a greater range . (3) the critical Ma number decreases as the aspect ratio increases , and increases as the radius ratio increases . In the the annular liquid pool free surface , the buoyancy of the introduction will make the critical Ma number increases, postpone flow instability , liquid pool is more shallow , buoyancy effects are more obvious . Under the same conditions , the upper part of the solid wall critical Ma number smaller , flow easier instability . Annular cavity in the upper part of the solid wall , the buoyancy of the introduction will make the critical Ma number decreases, the flow easier instability .
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