横向剪切气流中气液两相环状流射流液膜的破碎与雾化

The jet mixing has been extensively applied in military and civil fields. The aerodynamic forces can intensify the instability of the liquid jet and promote the breakup and atomization. Based on this, a novel mixing technique is proposed by injecting the gas-liquid annular flow jet into the crossflow. In the mutual influence of both inside gas flow and outside crossflow, the instability of the liquid sheet of the annular flow jet is intensified and the breakup and atomization are promoted effectively, and hence an efficient mixing between the gas-liquid annular flow jet and the crossflow can be achieved. The breakup and atomization of the liquid film of the annular flow jet are significantly different from that of other forms of liquid jet in the mutual influence of both inside gas flow and outside crossflow. In the crossflow, the breakup and atomization of the liquid sheet of the gas-liquid annular flow jet is a complex nonlinear and dynamic process and has complex phase interface structures. Through analytical and experimental methods, the project is to obtain the breakup and atomization characteristics of the liquid sheet of annular flow jet in crossflow, and to illustrate the breakup mechanisms and the critical breakup dynamic conditions of the liquid sheet. Studies on the formation and development of the vortices induced by the interaction of the gas-liquid annular flow and the crossflow, as well as the influence mechanism of the vortices on the breakup and atomization of the liquid sheet will also be included. A better knowledge of the dynamic interaction between the gas-liquid annular flow jet and the crossflow will be obtained. This project achievements will expand the research field of jet mixing, and will benefit in relevant applications of the mixing enhancement between the gas-liquid annular flow jet and the crossflow. Research results show great academic significance and applicable potential.

射流掺混在民用及国防等领域具有重大应用需求。气动剪切作用可增强射流液体的不稳定，促进液体的破碎与雾化。基于这一原理，本项目提出了采用气液两相环状流射流与横向气流掺混这一创新思路。环状流射流不同于传统的射流方式，横向气流环境中，受内侧剪切气流与外侧横向气流共同作用，液膜更容易发生破碎与雾化，从而实现与横向气流的高效掺混。横向剪切气流中环状流射流液膜的破碎与雾化呈现高度非定常特性与复杂的相界面结构。通过机理实验和理论分析相结合，获得横向剪切气流中环状流射流液膜的变形、破碎与雾化基本规律，查清液膜破碎机制和临界破碎动力学条件、流场中涡结构及其对液膜破碎与雾化的影响机制，揭示横向剪切气流中环状流射流液膜的破碎与雾化机理，掌握环状流射流与横向剪切气流相互作用的系统规律。本项目拓宽了射流掺混研究领域，为相关行业应用环状流射流与横向气流高效掺混组织提供了理论支撑，具有重要的学术价值和应用前景。

环状流射流与横流掺混在民用及国防等领域具有重要应用前景。本项目采用机理实验、理论分析与数值模拟相结合的方法对横向剪切气流中气液两相环状流射流液膜的破苏与雾化过程开展了系统研究。首先针对环形管及复杂通道内气液两相环状流区影响液膜流动的液滴沉积与夹带过程建立了数理模型。其次对无横流条件下自由环状流射流液膜的破碎雾化特性开展了研究，发现了在中心气流作用下环状流射流液膜的破碎具有周期性和不稳定性；获得了射流液膜周期性破碎系统规律；查清了射流液膜存在爆式破碎、分段花瓣式破碎与环膜袋式破碎三种破碎形态并阐明了其破碎机制；给出了三种破碎形态无量纲判定准则和射流液膜的临界破碎高度计算关联式；采用数值模拟揭示了自由环状流射流液膜分段式破碎机理。在此基础上，对横向剪切气流作用下环状流射流液膜的破碎与雾化过程开展了研究，查清了横流作用下环状流射流液膜的宏观破碎特性和微观破碎机制并获得了参数影响系统规律；给出了横流影响下环状流射流贯穿轨迹关联式；提出了横流影响下环状流射流液膜破碎形态判定准则及破碎高度计算关联式；采用光学信息提取的方法对环状流射流雾化液滴粒径进行了分析，获得了不同工况下雾化液滴粒径分布及其影响规律。本项目拓宽了液体射流掺混研究领域，为相关行业实现气液两相环状流射流与横流的高效掺混组织提供了理论基础，具有重要的理论意义和应用价值。