基于FLUENT的等离子弧与熔池一体化数值模拟

Numerical Simulation on Plasma Arc and Weld Pool Integration Based on FLUENT

以计算流体力学和麦克斯韦电磁场理论建立了等离子弧和熔池一体化的数学模型,综合考虑了电弧电子移动传热和工件表面的辐射传热、金属的熔化凝固和液态金属的蒸发以及熔池内金属的对流传热等对工件温度分布的影响,计算得出阳极表面与电弧之间能量、电流密度等参数的传递关系,并分析了工件温度场和熔池在整个焊接过程中的瞬态变化情况。结果表明:阳极表面的热流密度和电流密度分布近似符合高斯分布;上表面熔池形状由焊接初期的圆形逐渐变为椭圆形;准稳态时熔池横断面为典型的酒杯状。通过与文献计算值的对比,验证了所建立模型的合理性。

A mathematical model for plasma arc and molten pool integration was set up according to the theory of computational fluid dynamics and Maxwell＇s theory. The effects of all the heat transfer caused by electron flow and radiation loss from the workpiece surface, the melting and solidification of the metal and the vaporization and convection heat transfer of the melted metal on the temperature distribution of workpiece were taken into account. The relationship of the energy, the current density, etc. from the arc to the anode surface was calculated. Then, the transient conditions of the temperature distribution and the molten pool shape during the whole welding process were obtained. The results show that the heat flux and current density distribution on the anode surface both approximate to Gaussian distribution. The molten pool shape on upper surface gradually changes from circular to oval and the shape on the cross-section in the quasi-steady state is wine glass-shape. The soundness of the model was verified by the calculated values from the literature.