中国激光, 2018, 45 (8): 0802001, 网络出版: 2018-08-11
定向洛伦兹力对激光熔覆熔池排气的影响 下载: 904次
Effect of Directional Lorentz Force on Molten Pool Exhaust in Laser Cladding
激光技术 激光熔覆 熔池 气孔 定向洛伦兹力 多物理场 laser technique laser cladding molten pool pores directional Lorentz force multi-physics field
摘要
采用稳态磁场和电场耦合形成定向洛伦兹力,基于多物理场耦合原理及网格变形法建立了定向洛伦兹力作用下的熔池模型,采用离散元法模拟了熔池内的气泡运动过程。与熔覆工艺条件相同但未施加外场时比较,结果显示,定向洛伦兹力具有优异的气孔调控能力。当洛伦兹力向上时,熔池的最高流速被抑制了62.5%,气泡运动方向向下偏转,熔覆层的气孔明显增多; 当洛伦兹力向下时,熔池的最高流速被抑制了25%,但气泡因所受浮力增大而逸出加速,熔覆层无气孔。仿真结果与实验结果吻合良好,验证了仿真模型的可靠性。
Abstract
The stationary magnetic and electric fields are coupled to form the directional Lorentz force. Based on the multi-physics field coupling theory and the mesh deformation method, the molten pool model under the effect of the directional Lorentz force is built, and the bubble movement process in molten pool is simulated by the discrete element method. The comparison of numerical results with and without directional Lorentz force but both under the same laser cladding process conditions indicates that the directional Lorentz force possesses an excellent ability to regulate pores. When the direction of the Lorentz force is upward, the maximum velocity of molten pool is suppressed by 62.5%, the gas bubble movement direction deflects downward, and the pores in cladding layers increase obviously. When the direction of the Lorentz force is downward, the maximum speed of molten pool is suppressed by 25%. Nevertheless, for the reason of the increase of the bubble buoyancy, the bubble is accelerated and escapes from the melting pool, and a dense cladding layer without any pores is obtained. The simulation results agree well with the experimental ones, which confirms the reliability of this simulation model.
胡勇, 王梁, 李珏辉, 张群莉, 姚建华, Volodymyr Kovalenko. 定向洛伦兹力对激光熔覆熔池排气的影响[J]. 中国激光, 2018, 45(8): 0802001. Hu Yong, Wang Liang, Li Juehui, Zhang Qunli, Yao Jianhua, Volodymyr Kovalenko. Effect of Directional Lorentz Force on Molten Pool Exhaust in Laser Cladding[J]. Chinese Journal of Lasers, 2018, 45(8): 0802001.