(1. 华东理工大学 无机材料系, 上海 200237;
2. School of Mechanical and Materials Engineering, University of Surrey, Guildford Surrey GU2 7XH, UK)
摘 要: 建立了旋转盘离心雾化熔滴飞行与凝固进程的一个数学模型, 并用Runge-Kutta方法进行数值求解, 模拟镍金属熔滴飞行与凝固的基本情况, 探讨过程和材料参数的影响。 结果表明: 在旋转盘离心雾化中熔滴经历了一个大的过冷, 其过冷度约为0.2Tm; 在整个飞行期间, 熔滴的冷却速率并不是常数, 在熔点附近冷却速率约为5×104 K/s; 角速度越大, 冷却速率越大, 熔滴开始和完成凝固所需时间越短, 雾化室可小些; 熔滴过热温度对熔滴过冷度和冷却速率影响不明显, 但完成凝固所飞行的距离增大, 从雾化室设计角度, 不宜采用大的过热温度。
关键字: 离心雾化; 旋转盘; 飞行与凝固; 数学模型
( 1. Department of Inorganic Materials, East China University of Science and Technology, Shanghai 200237, China;
2. School of Mechanical and Materials Engineering, University of Surrey, Guildford Surrey GU2 7XH, UK)
Abstract: A mathematical model of droplet dynamic and solidification progress during rotating disk centrifugal atomization was developed and numerically solved by Runge-Kutta's method. The flight and solidification of a nickel droplet was simulated. The effect of process and materials parameters was studied. The results show that the droplet experiences a large undercooling of about 0.2Tm and the cooling rate is not constant during the flight, about 5×104 K/s at the melting point. With increasing disk speed the cooling rate increases, and this leads an early start and completion of solidification. A small atomizing chamber can be used. The droplet superheat has a weak effect on nucleation temperature and cooling rate, but the flight distance at f=1 increases. Therefore, a high droplet superheat is not suitable for the design of atomizing chamber.
Key words: centrifugal atomization; rotating disk; flight and solidification; mathematical model