考虑自由面动态变形的振荡热-溶质毛细对流研究

The research on Marangoni convection under microgravity environment has been included in the guideline of experimental projects for the Chinese Manned Space Station. While, the theoretical knowledge on this kind of thermo-solutal capillary convection for people is very superficial. By comprehensive considering the factors of free surface deformation in floating zone, flow and heat transfer in floating zone, and magnetic fields, this project will deeply study the oscillatory coupling thermo-solutal capillary convection in floating zone. The dynamic deformation of free surface induced by the solutal capillary convection in floating will be measured, and the effect mechanism of concentration gradient on the instability of free surface will be studied experimentally. By considering the dynamic deformation of free surface, the model and software platform for coupling thermo-solutal capillary convection in floating zone will be developed, and the instability, oscillatory mechanism, and transition process for the oscillatory coupling thermo-solutal capillary convection in floating zone will be studied numerically. The effect mechanism of magnetic field on the coupling thermo-solutal capillary convection in floating zone will be discussed as well. The project aims at establishing the numerical simulation method, simulation platform and experimental technology for the oscillatory coupling thermo-solutal capillary convection in floating zone. Through the study on the coupling thermo-solutal capillary convection in floating zone as well as the instability of free surface, the effect of flow of coupling thermo-solutal capillary convection and its oscillation on the impurities in crystal and doping distribution will be obtained, and the structure characteristics of fluid flow and the instability mechanism in floating zone can be understood. The theoretical basis for the microgravity fluid management and material preparation on the Manned Space Station can be provided.

微重力环境下Marangoni对流研究已经被列入我国载人空间站实验项目指南。但是，人们对这类振荡耦合热-溶质毛细对流的理论认识还很肤浅。本项目将全面考虑浮区自由面变形、浮区内外流动与传热、磁场因素，深入研究浮区振荡耦合热-溶质毛细对流。测量浮区溶质毛细对流引入自由面动态变形，实验研究浓度梯度对自由面不稳定性的影响机制。开发考虑动态自由面变形的浮区耦合热-溶质毛细对流模型及软件平台，数值研究浮区振荡耦合热-溶质毛细对流不稳定性、振荡机理和转涙过程，探讨磁场对浮区耦合热-溶质毛细对流的作用机理。项目旨在建立浮区振荡耦合热-溶质毛细对流数值模拟方法、模拟平台与实验技术。通过对浮区耦合热-溶质毛细对流及自由面不稳定性的研究，掌握耦合热-溶质毛细对流流动及其振荡对晶体中杂质及掺杂分布的影响，理解浮区流体流动结构特征及流动失稳机制，为载人空间站微重力流体管理及材料制备提供理论基础。

微重力环境下Marangoni对流研究已经被列入载人空间站实验项目指南，未来将在载人空间站开展热-溶质毛细对流相关科学实验。针对振荡耦合热-溶质毛细对流研究存在的突出问题，本项目全面考虑浮区自由面变形、浮区内外流动与传热、磁场因素，深入研究了浮区振荡耦合热-溶质毛细对流。研究主要包括几个方面：（1）浮区溶质毛细对流引入自由面动态变形及其不稳定性实验；（2）考虑自由面动态变形的溶质毛细对流数值模拟；（3）考虑动态自由面变形的浮区耦合热-溶质毛细对流数值模拟，研究了浮区振荡耦合热-溶质毛细对流不稳定性与振荡机理；（4）数值研究了磁场对浮区耦合热-溶质毛细对流的作用机制。项目发展了浮力对流-热毛细对流流动竞争模型，提出采用磁场实现振荡热-溶质毛细对流的主动抑制，开发了熔区界面光学影像和位形数据的自主识别程序，建立了浮区振荡耦合热-溶质毛细对流数值模拟方法、模拟平台与实验技术。基于上述研究，掌握了耦合热-溶质毛细对流流动及其振荡对晶体中杂质及掺杂分布的影响，理解了浮区流体流动结构特征及流动失稳机制，为载人空间站微重力流体管理及材料制备提供了理论基础。总部位于加拿大渥太华的国际工程学网站“Advances in Engineering”公开报道了本项目取得的研究成果。