等离子弧焊接熔池演变过程的格子Boltzmann模拟与验证

发布时间：2018-07-07 10:12

本文选题：等离子弧焊接 + 熔池　；参考：《工程热物理学报》2017年05期

【摘要】：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。
[Abstract]:In this paper, the lattice Boltzmann method based on molecular dynamics theory is used to establish a two-dimensional mathematical model to describe the dynamic evolution of the molten pool in fixed-point plasma arc welding. The heat transfer and flow phenomena in the process of phase transformation are simulated. The combined heat source model of plasma arc is improved according to the characteristics of welding energy distribution, and the temperature, velocity distribution and tracing phase interface are solved by total-enthalpy model. The results show that the shape of the simulated fusion line is consistent with the experimental weld, and the computational accuracy and efficiency of the lattice Boltzmann simulation are better than that of the finite volume method based on the hypothesis of continuous fluid. The feasibility and superiority of the lattice Boltzmann method in plasma arc welding simulation are verified. The effect of flow on weld shape can not be ignored, and the flow mode of molten pool affects the temperature field. The velocity field and the degree of cooperation between the two directly affect the heat transfer on the solid line and promote the formation of the middle part of the weld.
【作者单位】：北京科技大学能源与环境工程学院;北京科技大学冶金工业节能减排北京市重点实验室;山东大学材料科学与工程学院;
【基金】：国家自然科学基金资助项目(No.50936003)
【分类号】：TG456.2

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