( 中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 为了探明紧耦合气雾化制粉过程中金属熔液在气流作用下的雾化机理， 采用降低金属过热度， 使部分金属液流在雾化过程中提前凝固的方法， 研究了开涡状况下(气体压力为2.1 MPa)金属液流的成膜机制。 结果表明： 雾化过程中液膜不是连续生成的， 而是以离散方式形成的； 开涡状况下的“实心锥”雾化存在将液滴挤压成液膜的成膜过程。 这个成膜过程可表述为： 金属液流进入回流区， 经“初次雾化”破碎成离散的液滴， 并在湍流层中进一步破碎细化， 从滞留点前端穿过马赫盘， 被挤压成厚度约为10～30 μm、 面积大约为10～50 mm2的液膜。
关键字: 雾化机理； 粉末； 流场
gas atomization in state of ‘opened’ wake
（ State Key Laboratory of Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract: By decreasing the over-heating, a amount of metal sheets were solidified in the process of high-pressure gas atomization. The results indicate that the process of filming is not continuous, but in a discrete way. There is a filming process in the condition of ‘opened’ wake, as referred to solid-cone atomization. The filming process is described as: the melt is disrupted into droplets firstly by recirculation gas, and further smashed into smaller droplets in the turbulent layer by violent turbulent eddies; while crossing the Mach-disc, the droplets are squeezed into sheets with the thickness of 10-20 μm, and the area around 30-40 mm2.
Key words: atomization mechanism; powder; flow structure
