同轴送粉喷嘴保护气体流场研究

为解决飞机结构损伤激光在线修复过程中同轴送粉喷嘴气体保护效果不佳的问题,利用粒子图像测速(Particle image velocimetry,PIV)和Fluent软件对喷嘴保护气体流场进行了研究。将喷嘴气流的同轴射流和同轴冲击射流的数值计算结果和实验测量结果进行了比较,分析了喷嘴气流速度变化对流场稳定性的影响。结果表明:喷嘴中心、内环和外环气流流速由内向外递减时可获得稳定的流场;喷嘴中心、内环、外环喷出的气流速度接近一致时,流场比较稳定;喷嘴中心气流速度小于内环和外环的气流速度时,工件表面出现漩涡,破坏了流场的稳定性。

Shielding Gas Flow Field on Coaxial Powder Feeder Nozzle

To improve the shielding effect of gas flow in laser on-line repair of aircraft structure damage,the shielding gas flow field on coaxial powder feeder nozzles is studied by particle image velocimetry(PIV) and Fluent software.Experimental and numerical simulation results of coaxial jets and coaxial impinging jets of nozzle gas flow are compared.The influence of change of nozzle gas velocity on stability of flow field is analyzed systemically.The results show that gas flow field tends to be more stable when the velocity of three-section gas flow decreases gradually from center to outer.When the three-section gas flow velocity is consistent,the flow state is the best.When gas velocity from center nozzle is smaller than that from outer ring,vortex is caused on the flat,and the stability of gas flow field is disturbed.