( 中南大學(xué) 粉末冶金國家重點(diǎn)實驗室，長沙 410083)
摘 要: 為了探明緊耦合氣霧化制粉過程中金屬熔液在氣流作用下的霧化機(jī)理， 采用降低金屬過熱度， 使部分金屬液流在霧化過程中提前凝固的方法， 研究了開渦狀況下(氣體壓力為2.1 MPa)金屬液流的成膜機(jī)制。 結(jié)果表明： 霧化過程中液膜不是連續(xù)生成的， 而是以離散方式形成的； 開渦狀況下的“實心錐”霧化存在將液滴擠壓成液膜的成膜過程。 這個成膜過程可表述為： 金屬液流進(jìn)入回流區(qū)， 經(jīng)“初次霧化”破碎成離散的液滴， 并在湍流層中進(jìn)一步破碎細(xì)化， 從滯留點(diǎn)前端穿過馬赫盤， 被擠壓成厚度約為10～30 μm、 面積大約為10～50 mm2的液膜。
關(guān)鍵字: 霧化機(jī)理； 粉末； 流場
gas atomization in state of ‘opened’ wake
YU Wen-tao, ZHANG Xin
（ 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
