毫秒与纳秒脉冲激光联合打孔过程中物质迁移机理的研究

项目名称： 毫秒与纳秒脉冲激光联合打孔过程中物质迁移机理的研究

项目编号： No.51205210

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 机械工程学科

项目作者： 秦渊

作者单位： 南京理工大学

项目金额： 25万元

中文摘要： 针对毫秒激光打孔中出现的小孔形状不规则及堵塞现象，本项目提出毫秒和纳秒激光联合打孔方法，利用等离子体爆轰波对材料表面产生的压力来增加物质迁移。进而拟开展双脉冲联合打孔的数值和实验研究。在毫秒激光打孔阶段，采用有限元方法数值模拟材料内的温度分布，判断喷溅的产生，追踪液-气间的界面，计算喷溅速率、迁移质量及小孔轮廓。继而依据小孔瞬时轮廓建立模型，利用光线追迹法分析小孔对入射光的吸收情况。再将结果作为热载荷，计算下一时刻的小孔轮廓。在双脉冲联合打孔阶段，研究等离子体热辐射和表面压力作用对物质迁移的影响。通过实验对上述结果进行检验。最后，将基于数值模型分析纳秒激光功率密度及两个脉冲间的延迟时间对打孔效率的影响，以获得最佳打孔参数。该项目对于增进理解毫秒激光打孔这个复杂的物理过程，提高打孔效率，改善打孔工艺，推动激光在工业中的应用具有重要的学术意义。

中文关键词： 双脉冲；激光打孔；有限元法；物质迁移；

英文摘要： To avoid the occurrence of irregular hole profile and closure in ms laser drilling, we propose to drill hole with double-pulsed (ms and ns) laser. In this way, the mass removal will be accelrated with the help of surface pressure due to the laser-supported detonation wave (LSDW) plasma. Hereby, the study of material removal in double-pulsed laser drilling is planned. For the stage of ms laser drilling, the raise of temperature will be simulated numerically by the finite element method. The starting of ejection will be predicted. The interface between liquid and gas will be traced. Meanwhile, the ejection velocity, the removed mass and the hole profile will be obtained. After that, a hole model will be built according to the transient hole profile. With the ray-tracing method, the laser absorption inside the hole will be studied. The result of which will be taken as a heat source for the calculation of the hole profile in the next time step. For the stage of double-pulsed laser drilling, the effect of the plasma emission and the surface pressure on the material removal will be investigated. Besides, some experiments will be carried out to verify the calculated results. Finally, to obtain the optimum drilling parameters, the influence of ns laser power intensity and the delay time to the drilling efficiency will b

英文关键词： Combined pulse；Laser drilling；Finite element method；Migration of material；