空间蒸发热质传输与流体界面效应实验研究与理论分析

Evaporation process of liquid drops attached on substrates is widely used in thermal management engineering involved ground and aerospace industry. Research on the coupling of interfacial heat mass transfer and flow behaviors has become a hot research topic in this typical vapor-liquid-solid physical system. Systematic study need to be performed in the view of phase change heat transfer and interfacial flow dynamics, taking into the influence of evaporating effect and surface-tension-driven convection account, such as the convection flow in vapor and liquid drop, heat transfer between vapor, liquid drop and solid substrate. Based on the space experiments of evaporating drops attached on different substrates onboard Chinese SJ-10 Satellite, using in-depth analysis of space experimental results, comparison experiment on ground, numerical simulation methods and theoretical analysis, present project applies for a proposal to study the coupling mechanism of phase change heat transfer and interfacial effect: (1) comparison analysis between space and ground experimental results to study the influence mechanism of gravity effect on the vapor-liquid interfacial heat transfer; (2) thermal convection instability inside the liquid drop by means of theoretical analysis and experimental investigation; (3) transient process simulation of liquid drop evaporation in vapor-liquid-solid phase. Integration of space experiments and ground study in the present project will have important scientific significance to improve the understanding of coupling mechanisms involved thermodynamics and flow dynamics in evaporating drops. In the meantime, the results will also lay a solid foundation for optimal design of thermal mechanical engineering in ground and space industry.

附壁液滴蒸发涉及界面热质输运和流体动力学的耦合，其在地基高效热能机械和航天工程热管理体系有重要的应用。本课题依托实践十号科学卫星获得的空间微重力下液滴蒸发科学实验数据，采取空间实验、地基实验研究、数值模拟和理论分析相结合的研究方法，综合考虑气-液相对流流动和气-液-固相的热量输运，关注蒸发传热和界面动力学效应，揭示蒸发效应与表面张力驱动对流的耦合。拟分别开展以下三方面的研究：(1)天基和地基实验比对分析，研究重力效应对传热影响；(2)理论分析和实验研究协同研究蒸发液滴内热对流稳定性；(3)数值模拟在气-液-固多场耦合下蒸发瞬态过程。本项目是空基和地基研究的有机结合，将较为真实地再现附壁液滴蒸发过程中涉及的界面热力学和流动动力学耦合机制，具有重要的学术意义，同时将为改善地面和空间热能机械的传热效率提供坚实的理论基础。

液体蒸发涉及界面热质输运和流体动力学的耦合，其在地基高效热能机械和航天工程热管理体系有重要的应用。本课题以实践十号科学卫星空间微重力下液滴蒸发科学实验为基础并延申，开展了地基实验、空间实验结果比对、蒸发相变过程数值模拟和界面稳定性分析的科学研究，对相变和热对流耦合影响下的热、质、流输运过程进行系统的研究。主要研究要点包括（1）地基蒸发对流实验技术实现与天地对比实验和重力影响分析；（2）相变界面热质传输与热对流特性耦合规律研究；（3）复杂界面流动与不稳定性特性理论研究。本项目完成了一套精确化、批量化和可视化的空间和地基液滴形貌演化和瞬时蒸发速率处理软件。搭建了一套可变环境温度、可变环境压力的蒸发相变和热对流地基实验研究系统，通过天地对比试验并结合液滴蒸发过程数值模拟比较了重力效应对液滴形貌、蒸发速率、传热与对流流型的影响。发展了相变界面热质传输与热对流特性耦合数值模拟模型、界面稳定性分析方法，描述了热毛细对流、浮力对流、相变界面传热传质以及蒸气对流扩散之间的相互影响，研究了振荡相变热毛细对流的不稳定性特征和对流转捩途径，研究了无限大薄液层热毛细流运动过程中弹性效应、重力效应等物理因素对临界Renolds数、失稳模态及频率的影响机制。本项目是空基和地基研究的有机结合，较系统的研究了液体蒸发过程中涉及的界面热力学和流动动力学耦合机制，对改善地面和空间热能机械的传热效率具有理论指导意义。