微重力环境下浮区耦合热-溶质毛细对流蕴含着丰富的流体动力学行为及复杂的热质传输过程。由于目前对流动的失稳机制、演化动力学规律、自由表面振荡特性等研究还不充分，本项目拟以数值模拟为主结合一定的实验，对微重力环境下浮区耦合热-溶质毛细对流问题进行研究。发展基于Level set方法的多相多组分自由表面流动数值模拟程序，研究微重力环境下浮区耦合热-溶质毛细对流不稳定性的产生条件、形成机制和三维时空演化特征，揭示热Marangoni数与溶质Marangoni数比值、几何比、体积比和Pr数等对耦合热-溶质毛细对流失稳的临界Marangoni数、失稳模态及自由表面振荡的影响规律；研究残余重力和重力跳动对浮区耦合热-溶质毛细对流失稳的临界Marangoni数、失稳模态及自由表面振荡的影响，分析几何比、体积比、Pr数等对浮区共振频率的影响。本项目的顺利实施将为空间微重力环境下晶体生长提供理论指导。

Thermo- and solutocapillary convection in floating zone under microgravity condition contains complex fluid dynamics and heat and mass transfer process. At present, study on flow instability mechanism, dynamic rules of evolution and free surface oscillation is still not sufficient. Therefore, the flow instability of coupled thermo- and solutocapillary convection will be investigated by numerical simulations and some experiments in the subject. A numerical simulation code of multiphase and multi-species of free surface flow based on Level set method will be developed. The generation condition, form mechanism and three-dimentional space-time evolution characteristics of the coupled thermo- and solutocapillary convection will be investigated, and the effects of ratio of thermal Marangoni number to solutal Marangoni number, aspect ratio, volume ratio and Pr number on critical Marangoni number，unstable flow mode and oscillation of free surface will be revealed. Furthermore, the effect of residual gravity and gravity jitter on critical Marangoni number, flow characteristics and free surface oscillation also will be studied, and the effect of aspect ratio, volume ratio and Pr number on resonance frequency of the floating zone will be analysed. All these investigations will provide theoretical guidance for crystal growth process under microgravity environment.