陈海俊,朱刚贤,贺继宏,王丽芳.激光内送粉变姿态熔覆非水平熔池流场的数值模拟[J].表面技术,2024,53(9):190-199, 208.
CHEN Haijun,ZHU Gangxian,HE Jihong,WANG Lifang.Numerical Simulation on Flow Field of Non-horizontal Molten Pool by Laser Cladding Based on Inside-beam Powder Feeding with Variable Posture[J].Surface Technology,2024,53(9):190-199, 208 |
| 激光内送粉变姿态熔覆非水平熔池流场的数值模拟 |
| Numerical Simulation on Flow Field of Non-horizontal Molten Pool by Laser Cladding Based on Inside-beam Powder Feeding with Variable Posture |
| 投稿时间：2023-01-30 修订日期：2023-08-02 |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.09.018 |
| 中文关键词: 激光熔覆 光内送粉 变姿态 熔池流场 数值模拟 |
| 英文关键词:laser cladding inside-beam powder feeding variable attitude molten pool flow field numerical simulation |
| 基金项目:国家级大学生创新创业训练计划项目(202110285032);江苏省大学生创新创业训练计划项目(202110285032Z);苏州市科技计划项目(SYC2022143);国家重点研发计划项目(2016YFB1100300) |
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| 中文摘要: |
| 目的 提高激光内送粉变姿态熔覆层成形质量，对变姿态熔覆时非水平熔池流场随基板倾斜角的演变规律进行研究。方法 首先，利用FLUENT软件中离散相模型对喷嘴流场进行模拟，获取粉末频次的分布规律。其次，采用流体体积法耦合熔化/凝固模型对熔池流场进行计算。通过施加质量源项引入同步送粉，施加能量源项模拟激光热输入，选取姿态角为30°、60°、90°进行计算，对熔池流场及熔覆层界面进行追踪分析。最后，基于激光内送粉熔覆工艺进行实验测定。结果 粉斑内粉末量呈“中间均匀，两端密集”的分布规律。熔池流动为“双环流”分布特征，但流动方向受重力影响，产生偏转。取3种姿态角计算时间同为0.3 s时，熔池中心处流体的偏转角分别为2°、4°、6°，并且随着倾斜角的增大，熔覆层高度分别增加了0.28%、0.83%、1.45%，熔覆层宽度减小了1.19%、1.28%、1.73%，熔覆层顶点偏移量增大到48.08、86.54、105.76 μm。最后结合实验测定，数值计算与实验结果一致。结论 Marangoni应力使得激光内送粉熔覆熔池流体产生由中心向边界流动的“双环流”分布特征，非水平熔池流动方向受重力影响产生偏转。随着基板倾斜角增大，熔覆层截面高度增加、宽度降低、顶点偏移量增加。为提高不便摆平非水平基面的激光内送粉变姿态熔覆再制造成形质量提供了指导。 |
| 英文摘要: |
| Laser cladding and laser remanufacturing technology is based on horizontal reference planes at present, however, this way greatly limits its extensive application. The molten pool flow behavior of the laser cladding has a direct impact on the morphology and forming quality of the cladding layer. However, it is difficult to observe and study the flow behavior in the molten pool by experimental method due to the limitation of high temperature and instantaneous evolution of the molten pool. Consequently, the simulation analysis of the heat transfer, flow behavior and morphology evolution in the molten pool by numerical simulation technology is a research hotspot in laser cladding technology. In addition, the flow field distribution of the non-horizontal molten pool is still lack of systematic research with variable attitudes based on inside-beam powder feeding way by laser cladding. In order to improve the forming quality of cladding layers under variable attitudes based on inside-beam powder feeding, the flow field evolution rules of a non-horizontal molten pool with a substrate inclination angle were studied. In this paper, the discrete phase model based on FLUENT Software was adopted to compute the flow field of the nozzle and obtain the powder distribution rules. And then, the flow field of the molten pool was calculated based on the Volume of Fluid and Melting/Solidification Model. Attitude angles of 30°, 60° and 90° were chosen to compute the flow field of the non-horizontal molten pool, respectively. The flow field of the molten pool was tracked and the interfaces of the cladding layer were analyzed by applying the mass source item and the energy source item to simulate the process of synchronous powder feeding and laser thermal input. Finally, experimental measurements were carried out based on the inside-beam powder feeding cladding process. The results showed that the powder distribution in the powder spot was "even in the middle and dense at both ends". The flow field of the non-horizontal molten pool was characterized by "double annular flow" distribution, but the flow direction was deflected due to the influence of gravity. When the computation time of three attitude angles was 0.3 s, the deflection angles of the fluid at the center of the molten pool were 2°, 4°, and 6°, respectively. With the inclination angle increased, the height of the cladding layer increased by 0.28%, 0.83% and 1.45%, the width of the cladding layer decreased by 1.19%, 1.28% and 1.73%, and the vertex offsets of the cladding layer increased to 48.08 μm, 86.54 μm and 105.76 μm. Finally, the numerical calculations were consistent with the experimental results through the experimental determination. The Marangoni stress makes the fluid flow in the molten pool from the center to the boundary with a double-circle distribution characteristic. The flow direction of the non-horizontal molten pool is deflected by the influence of gravity. While the inclination angle increases, the height of the cladding layer increases, the width of the cladding layer decreases and the vertex offset of the cladding layer gradually increases. It provides guidance for improving the laser cladding and laser remanufacturing quality in the light of parts that are inconvenient to flatten the non-horizontal base surface by the inside-beam powder feeding way. |
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