中文摘要：

建立了激光熔覆同轴送粉喷嘴的载气一粉末两相流场计算模型，三维模型考虑了进粉管和粉末腔对粉末输送的影响。分析了三维状态的载气分布情况，揭示了粉末在不同粉末腔结构的同轴送粉喷嘴内碰撞与运动规律，以及粉末喷射汇聚情况；针对可调式同轴送粉喷嘴的调节性能进行了分析，依据分析设计了一种可调式同轴送粉喷嘴。计算结果表明，改变粉腔直径、高度及内壁倾角长度对粉末离开喷嘴后的发散程度略有影响，对粉末汇聚稳定后的浓度和粉末焦点半径影响较小；调节同轴送粉喷嘴的锥体相对位置，可以实现粉末焦点相对激光束的垂直位置调节。

英文摘要：

Established laser cladding coaxial send powder nozzles output carrier gas/powder two phases flow field calculation model. The 3D-model considers the powder tube and powder conveying influence cavity. Analysis of gas distribution reveals the powder in different powder cavity structure within the coaxial send powder nozzles, and collides with the motion law of powder injection gathering situation. According to the adjustable coaxial powder nozzle regulation performance, an adjustable coaxial powder nozzle is designed. The calculation results show that the diameter of cavity, change powder, height and wall length on the powder nozzle have slightly influence on the powder spread after together. And have less influence on radius of steady con centration and powder focus. Adjust the cone coaxial send powder nozzles, may realize the relative position of laser powder fo cus relatively vertical position adjustment.