气体熔池耦合活性TIG焊电弧传热传质过程的数值分析

Numerical analysis of heat and mass transfer process of welding arc during gas pool coupled activating TIG welding

针对气体熔池耦合活性TIG焊电弧,建立焊接电弧传热传质过程的数学模型.采用简化阴极边界层模型对阴极与电弧耦合求解,计算得到气体熔池耦合活性TIG电弧等离子的温度、氧气分布、等离子体流速、电势和电流密度等特征参数,并与传统TIG电弧进行对比.结果表明:氧气主要分布在电弧外围,只有少量进入电弧内部;与TIG电弧相比,相同焊接参数下气体熔池耦合活性TIG焊电弧温度上升,等离子体流速增大,电弧略有收缩,阳极表面电流密度、热流密度与电弧压力峰值均增大.

A mathematical model is established to reveal heat and mass transfer process of gas pool coupled activating TIG welding arc. The coupling of welding arc with cathode is numerically simulated by using simplified cathode sheath model. By means of computation, the characteristic parameters of welding arc such as the plasma temperature, the distributions of oxygen, velocity of plasma, electric potential, and current density are obtained and compared with those of the arc of traditional TIG welding. The results show that oxygen is mainly distributed in the arc periphery, and only a small amount diffuses into the arc, compared with the arc of TIG welding, the arc temperature and velocity of plasma will increase, and the peak values of current density, heat flux, and arc pressure at anode surface increase under the same welding conditions.