铝合金颗粒低压冷喷涂喷嘴几何参数优化设计

Optimization Design of Geometry Parameters of Low-Pressure Cold Spray Nozzle for Aluminium Particles

摘要: 因低压冷喷涂沉积精度较低，无法实现微细化喷涂，为提高其精度，本研究目标是优化其中常用的收缩–发散–直筒型喷嘴的几何结构参数，改善气流场状态，以获得更高质量的沉积。结果表明，喉部直径是影响颗粒速度的关键参数，较大的喉部直径可以产生更高的颗粒速度。此外，发散段长度和直筒段长度也会影响颗粒速度，需要优化选择，粉末的注入角度越小，颗粒的冲击速度越小，但角度超过60度以后，对颗粒的冲击速度影响不大。实验结果验证了喉部直径不应小于1.8 mm，否则无法形成有效的涂层。本文通过仿真和实验对低压冷喷涂喷嘴进行了几何参数优化，为进一步提高低压冷喷涂精度提供了参数设计指导。

Abstract: Due to the low deposition resolution of low-pressure cold spray, it is unable to achieve fine coating. To improve its accuracy, the aim of this study is to optimize the geometrical parameters of the commonly used convergent-divergent-straight nozzle to improve the gas flow field status for higher quality deposition. The results show that the throat diameter is the key parameter affecting particle velocity, and a larger throat diameter can generate higher particle velocity. In addition, the length of the divergent section and the straight section also affect particle velocity, and need to be opti-mized. The smaller the powder injection angle, the smaller the impact velocity of particles, but the impact on particle velocity is not significant when the angle exceeds 60 degrees. Experimental re-sults verify that the throat diameter should not be less than 1.8 mm, otherwise an effective coating cannot be formed. This paper optimizes the geometrical parameters of the low-pressure cold spray nozzle through simulation and experiments, providing parameter design guidance for further im-proving the accuracy of low-pressure cold spray.