论文部分内容阅读
本文应用基于分子动理论的格子Boltzmann方法,建立了描述定点等离子弧焊接熔池动态演变过程的二维数理模型,对相变过程的传热与流动现象开展模拟;根据焊接过程能量分布特点改进等离子弧的组合式热源模型,采用total-enthalpy模型求解温度、速度分布及追踪相界面。研究结果表明,模拟的熔合线形状与实验焊缝吻合,格子Boltzmann模拟得到的计算精度及计算效率均优于基于连续流体假设的有限容积法,验证了格子Boltzmann方法用于等离子弧焊接模拟的可行性和优越性;熔池中出现两个方向相反的环流,流动对焊缝形状的作用不容忽略;熔池的流动方式影响了温度场、速度场及二者协同度,直接影响固相线上的热量传递,促进了焊缝中部凸起的形成。
In this paper, a lattice Boltzmann method based on molecular dynamics theory was used to establish a two-dimensional mathematical model describing the dynamic evolution process of a fixed-arc plasma arc welding pool. The simulation of heat transfer and flow phenomena during the phase transition was performed. According to the energy distribution characteristics of the welding process, Arc combined heat source model using the total-enthalpy model for temperature, velocity distribution and tracking phase interface. The results show that the simulated weld line shape is in agreement with the experimental weld, and the computational accuracy and computational efficiency of the lattice Boltzmann simulation are better than the finite volume method based on the continuous fluid assumption. The feasibility of the lattice Boltzmann method for plasma arc welding simulation is verified Sexuality and superiority. There are two circulation flows in the pool with opposite directions. The effect of the flow on the shape of the weld can not be ignored. The flow pattern of the pool affects the temperature field, the velocity field and the degree of synergy, which directly affects the solidus line Of the heat transfer, promote the formation of the weld central bulge.