基于扰动波的HVAS液滴耦合振动特性分析

高速电弧喷涂过程中熔融金属液滴的振动特性对喷涂涂层性能具有决定性作用，但限于实验技术很难检测液滴的动力学行为，因而利用扰动波理论建立了气流和液滴的耦合振动方程组，并数值求解获得了喷涂气流最不稳定波数，与Bradley的数据曲线进行了比较，二者呈现出较好的吻合性，误差在士2％之间，验证了所建立的HVAS小扰动液滴模型是有效的；根据HVAS液滴耦合振动模型分析了不同喷涂气流及其速度对不同熔融金属的相应HVAS液滴振动特性。结果表明，HVAS过程中用N2具有一定的优势，且增加气流速度有利于提高喷涂涂层的结合强度，从而为HVAS过程中的材料选择与工艺控制提供了基本的理论依据。

Analysis wave-like disturbance of coupling vibration characteristic of HVAS droplets

Vibration characteristics of molten metal droplets are the decisive effects to performances of high velocity arc sprayed coating,but it is hardly to test the dynamic action of liquid droplets owing to the limitation of experimental technique.Though it established the sprayed gas and liquid droplet coupling vibration system of equations based on wave-like disturbance,numerical solutions for the governing equation,a fastest-growing wave number is derived.Comparing of predicted fastest-growing wave number and data of Bradley,the deviation within the±2% limits,its efficiency is validated to the gas liquid droplet coupling vibration system of equations.Using the coupling vibration system of equations,analyzed the effects of different gas type,different gas velocity and different molten metal type to vibration characteristics of HVAS droplets.The results show that N₂ gas is better selected as sprayed gas,adhesive strength of the spraying coating increase with an increase in the gas velocity,thereby provides theoretical evidence for choice of spraying materials and control processing parameters of HVAS.