Experimental investigations on breakup characteristic of single droplet in the core/bag breakup regime inthe continuous uniform heating airflow
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摘要: 为了获得热气流中单液滴液核/袋状破碎特性,采用高速摄像机对液滴变形、破碎过程进行了捕获.实验设计工况下所得结果表明:①液核/袋状破碎过程是液滴中液体流动与外界气动力共同作用下发生的,可以分为伞形破碎与勺形破碎;②液滴初始直径减小、气流温度增加,都可以降低液滴发生液核/袋状破碎所需最小气动力;③液滴破碎特征时间,随气动力增加呈负增长变化趋势,其值与变化梯度都随液滴初始直径增加而增大;④子液滴质量分数随气动力增加而增加,且随液滴初始直径增加而减小;⑤子液滴群质量分数的空间离散度都随气动力增加而增加.Abstract: In order to obtain characteristics of single droplet deformation and breakage in a continuous and uniform air jet flow, the highspeed cameras were applied to measure the single droplet deformation and breakage. In the experimental conditions, experimental results show that: (1) The process of droplet deformation and breakage in the core/bag breakup regime is caused by the combination effects of liquidflow and external aerodynamics. It can be divided into umbrella-type breakup regime and dipper-type breakup regime. (2) The reduction of original diameters of droplet and the increase of airflow temperature could decrease the minimum requirements of aerodynamic force on the core/bag breakup. (3) The characteristic time of droplet breakup has a negative relationship with the aerodynamics, while its value and change gradient are both positively associated with the original droplet diameter. (4) The percentage of sub droplet quality raises with the increase of aerodynamics, but decreases with the increase of droplet original diameter.(5) The spatial dispersion of quality percentage of sub droplet increases with the rise of aerodynamics.
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Key words:
- droplet breakup /
- atomization /
- heated air flow /
- sprays /
- highspeed cameras
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