喷雾沉积ZA27合金微滴热过程物理模型与数值分析

基金项目:

航空科学基金和国家教委博士点基金资助

详细信息

PHYSICAL MODEL AND MATHEMATICAL ANALYSES ON THERMAL PROCESS OF SPRAY-DEPOSITED ZA27 ALLOY DROPLETS

摘要: 采用牛顿冷却、均质形核和连续生长模型,建立雾化工艺参数与飞行中微滴热过程的数学模型,并用ZA27合金进行数值计算和分析。结果表明,在较低雾化压力(~0.7MPa)下,直径20~80μm微滴的冷却速率在10⁶~10⁴K/s之间。过冷度与微滴直径的对数呈线性关系。直径越大所能达到的最大过冷度越小,20μm直径的微滴过冷度约为0.2Tm。一旦形核,凝固将在较短的飞行距离内(0.04m)完成。
- 锌基合金 /
- 快速凝固 /
- 喷雾沉积
Abstract: The technological parameters and methematical model of in-flighting droplet thermal process have been established by adopting Newton cooling, homogeneous nucleation and contineous growth model,and the mathematical calculation and analyses for ZA27 alloy have been conducted. Results show that under lower atomization pressure(~0. 7MPa), the cooling speed of droplets with a diameter of 20~80μm is in a range of 10⁶~10⁴K/s. The logarithm of undercooling degree to droplet diameter exhibits a linear relation. The bigger the size is, the smaller the maximum undercooling degree can be reached. The undercooling degree of droplets with a diameter of 20μm is about 0.2Tm. Once nucleus is formed in flight,the solidification will be completed within a shorter flying distance(0. 04m).
- zinc based alloy /
- rapid solidification /
- spray deposition