侧吹气体喷嘴位置对光致等离子体尺寸特征的影响
The Influence of Side-blown Assist Gas Nozzle Position on Plasma Characteristic Dimensions
张菁, 蔡艳
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作者单位：上海交通大学 材料科学与工程学院
中文关键字：喷嘴位置；数值模拟；光致等离子体；快速定位装置
英文关键字：nozzle position; numerical simulation; laser induced plasma; fast positioning device
中文摘要：高功率CO2激光焊接过程中侧吹气体喷嘴位置及角度变化会对光致等离子体的尺寸特征产生影响。本文基于计算流体动力学，建立了二维非稳态模型，计算不同喷嘴位置、喷嘴角度下气体在工件表面产生的压力、水平气体流速和保护气体在整个环境氛围中所占的比率，指出利于抑制等离子体的气体喷嘴位置最佳区间。设计了基于十字型激光的喷嘴位置快速定位装置。实验结果表明侧吹气体喷嘴的位置及角度在工业生产中具有很重要的作用，适当的喷嘴位置配合较小的保护气体流量同样可以达到抑制等离子体保证焊接质量的效果，同时可以降低成本，节约资源。
英文摘要： During high power CO2 laser welding process, the position and angle of side-blown assist gas can influence plasma characteristic dimensions. Based on computational fluid dynamics, a two-dimensional unsteady state model was established to calculate the gas static pressure, gas flow horizontal velocity and helium volume ration under different nozzle positions and nozzle angles. Then the best range of nozzle position for controlling plasma dimensions was pointed out. A side-blown assist gas nozzle fast positioning device based on cross laser was designed to help improve welding process. Experimental results show that the position and angle of side-blown gas nozzle have played an important role in industrial production. Proper gas nozzle position with less gas flow rate can also inhibit plasma and ensure welding quality while reducing costs and saving resources.