射流凝结气液界面动态演化及诱发噪声机理研究

Vapor jet condensation in fluids is frequently encountered in nature, and has extensive applications in the fields of aerospace rocket engines and power production. The process of jet condensation results in severe transient characteristics including multiscale interfaces and highly turbulent flows. The transient characteristics make getting an accurate description of the micro-mechanisms of the interface evolution and noise generation difficult. Thus, we propose to explore the underlying mechanisms of the multiscale interface evolution and the noise generation involved in bubble breakup, coalescence, and annihilation during vapor jet condensation in a subcooled liquid. The complex interactions of multiphase flow, turbulent mass-energy transport from interface condensation and evolution, and noise generation, are the key and difficult problems to reveal the mechanisms of jet condensation. Experiments on the mechanisms of liquid-vapor interface evolution and noise generation will be conducted after development of measurement and analysis methods. A multi-flow-field model will be developed with special consideration of both the condensation and multiscale characteristics of the liquid-vapor interface based on fundamental multiphase and thermal physics. Initially, the turbulent multiscale interface of the vapor bubble breakup, coalescence, and annihilation will be investigated systematically. Afterwards, the mechanisms regulating vortex structures and their interaction with the multiscale liquid-vapor interface will be studied. Finally, the physical mechanisms of the heat and mass transfer and the resulting noise generation due to the evolution of the multiscale liquid-vapor interface will be investigated. The results would be helpful for further theoretical study on the mechanisms of condensation of a vapor jet in a subcooled liquid. This project will provide scientific basis for engineering applications to optimize the physical geometry of the vapor jet relative to the subcooled liquid to allow for rapid condensation and minimization of noise generation.

射流凝结现象广泛存在于自然界，在航天火箭发动机及能源电力等领域具有重大应用需求。射流凝结具有相变、强湍流和界面多尺度等剧烈的瞬态特性，致使气液界面能质输运与噪声机制难以准确描述。由此，本项目提出从射流凝结典型气液界面过程出发，探索耦合冷凝相变的多尺度气液界面破碎、聚并和湮灭动态演化及诱发噪声机理，其关键基础是认识流场、热场和声场等复杂多物理场耦合作用下，牵涉界面冷凝相变与多尺度演化、强湍流输运和噪声产生的多相相间作用及能质输运机理。本项目基于多相流热物理学基础理论，发展气液界面演变及噪声的测量分析方法并开展机理实验，构建考虑气液界面冷凝相变和多尺度等特殊性质的多流场模型，系统研究气液界面在湍射流场中破碎、聚并和湮灭过程的动态演化规律，阐明旋涡结构对气液界面输运和动态演化的影响机制，揭示气液界面动态演化诱发噪声的传热流动机理，为相关行业应用气液两相射流的高效凝结过程组织提供基础理论和方法。

射流凝结现象广泛存在于自然界，在航天火箭发动机及能源电力等领域具有重大应用需求。本项目针对气液两相射流凝结过程中的相界面时空动态演化及流场波动参数进行了系统深入的研究。发展了气液两相射流相界面特征参数识别方法和分析理论，获得了蒸汽射流连续相界面基本特征，构建了管内受限空间气液两相射流凝结流型图。揭示了蒸汽射流相界面不稳定性规律及其转变机制，获得了射流在横向剪切液流中的贯穿深度。揭示了蒸汽质量流速、液体过冷度等关键因素对传热流动及相场波动参数的影响规律，阐明了冷凝界面特征与多相流场波动特性的内在关联机制，实现了基于气液两相流场波动参数数理统计特征的射流凝结界面类型实时在线预报。为相关行业应用气液两相射流的高效凝结过程组织提供基础理论和方法。在Int. J. Heat Mass Transf.、Chem. Eng. Sci.、Appl. Therm. Eng.、Exp. Therm. Fluid Sci.等知名国际期刊已发表SCI论文12篇，其中第一作者9篇，发表EI论文5篇；国际国内学术会议论文报告共12篇；培养已经毕业硕士生4名；项目负责人徐强于2018年12月晋升副教授。