雾化Fe-58％Sn合金微滴外围气流场的模拟与数值分析
Simulation and numerical analysis of the peripheral airflow field of atomized Fe-58％Sn alloy microdroplet
彭银利 1杨卫斌 2李梅 2刘刚 1赵亚忠 1解芳1
作者信息
- 1. 南阳理工学院河南省增材制造航空材料工程研究中心,河南南阳 473004;南阳理工学院南阳市增材制造技术与装备重点实验室,河南南阳 473004
- 2. 南阳理工学院河南省增材制造航空材料工程研究中心,河南南阳 473004
- 折叠
摘要
基于k-ε湍流模型,实验模拟了 Fe-58％Sn合金液滴在气流中强制冷却时的外围流场,分析了其流动和传热过程,确定了换热系数h,并讨论了流场对粉末内"核"结构位置的影响.结果表明:微滴迎风面气体平均流速低于通入气流速度,但高于背风面回流区内的气体流速.微滴表面气体流速v和换热系数h与旋转角θ关系密切,呈先增大后减小趋势.其中,在θ=2π/5时,v和h值最大;在θ=π位置,v和h最小,且峰值的位置与微滴直径无关.此外,计算还表明:微滴尺寸对外围气流场的影响不明显,在10m/s流场中,直径为400、600和800 μm的合金微滴最大换热系数差分别为727.8、779.7和836.7W·(m-2K-1).表面换热差异将导致微滴内部"核"结构由几何中心向背风面不断偏移,最终可能形成"核"偏离中心位置的核/壳结构形貌.本研究对揭示核/壳结构的形成机制及新型智能结构材料设计具有重要指导意义.
Abstract
Based on the k-ε turbulence model,the peripheral airflow field of Fe-58％Sn immiscible alloy droplets is numerically simulated during its cooling process in the gas flow. By analyzing the flow and heat transfer proce-dures,the heat transfer coefficients h at each surface are determined,and the position of the "core" inside a pow-der is predicted. The results show that the average airflow velocity on the windward side of micro-droplet is low-er than that of the inlet gas,but it is higher than the airflow on the leeward side. Both the airflow velocity v and the heat transfer coefficient h on the micro-droplet surface are strongly dependent on the rotation angle θ,which first increase and then decrease as the rise in θ( 0＜θ＜π). The values of v and h reach the peaks at θ=2π/5,and they become the smallest ones at θ=π,and moreover the peak positions are independent of the micro-droplet di-ameter. Furthermore,the calculation results demonstrate that there is a little effect of micro-droplet size on the pe-ripheral gas flow field,and the maximum differences of heat transfer coefficient in the 10 m/s flow field for alloy micro-droplets with diameters of 400,600 and 800 μm are 727.8,779.7 and 836.7 W·(m-2 K-1),respectively. In addition,the different heat transfer condition contributes to the fact that the inner "core" structure is continuously shifted from the geometric center of the micro-droplets to the leeward side,eventually forming a core-off-center core/shell structure morphology after solidification. This study is of great significance to reveal the formation mechanism of the core-shell structure and the materials design of new intelligent structure.
关键词
难混溶/微滴/流场/k-ε模型/换热Key words
immiscible/micro-droplet/flow field/k-ε model/heat transfer引用本文复制引用
基金项目
国家自然科学基金青年项目(52201044)
河南省自然科学基金青年基金项目(212300410213)
南阳理工学院校级交叉学科项目和博士科研启动项目()
出版年
2024
NETL
NSTL
万方数据