毫秒激光打孔过程中熔融喷溅物的温度分析
时间:2018-03-05 15:45 来源:毕业论文 作者:毕业论文 点击:次
| 摘要本文对毫秒激光在金属铝上打孔过程中产生的熔融喷溅物的平均温度进行分析研究。首先简单介绍了激光打孔的相关实验及仿真研究现状，喷溅物产生的机理与条件。从实验出发，测量了光束半径为250 ，脉宽为1ms的不同能量激光的打孔深度和直径等值。建立了一文模型，假设质量迁移完全由液态喷溅所引起，并基于稳态热传导理论，推导了打孔速度的解析表达式，得到了打孔深度与液态喷溅物平均温度的关系。数值计算确定了熔融喷溅物的平均温度，激光能量气化损失率。并研究了喷溅物平均温度、气化损失率与激光能量的关系，不同能量激光作用下的温升所需时间。计算结果表明，当激光功率密度越大时，液态喷溅物的平均温度就越高，气化损失的激光能量也越多。随着作用激光能量的增加，激光能量气化损失率逐渐增加，打孔的效率越低。19237 关键词：激光打孔；喷溅物；气化损失 毕业设计说明书（论文）外文摘要 Title the Analysis of Temperature of Melting Spills in the Process of Millisecond Laser Drilling Abstract The average temperature of the molten spitting produced in the millisecond laser drilling process were analyzed in this article. First, we introduce the status of the laser drilling experiments and simulation and the mechanism of the generation of splashes briefly. Starting from experiment, we measured the depth and diameter of the hole when drilling with the laser with radius of 250um, the pulse width of 1ms and different energy. A one-dimensional model was established, and we assumed the mass transfer completely caused by liquid splashing. Based on the steady-state heat conduction theory, we deduced the analytical expressions of drilling speed, and we got the relationships of the average temperature of the liquid splashing and drilling depth. The average temperature of the molten splashes and the loss rate of laser energy by vaporization was determined by numerical calculations. We analyzed the relationship between the average temperature of splashes, the loss rate by vaporization and the energy of laser, and the time required when temperature rises under the effect of laser with different energy. The results showed that when the laser power density becomes larger, the average temperature of the liquid splashing rises, more energy loss by vaporization, and the efficiency of drilling becomes lower. Keywords: laser drilling; splashes; vaporization loss 目次 1 引言 1 1.1 激光 1 1.2 激光打孔 1 1.3 激光打孔的实验研究 2 1.4 激光打孔模拟研究 2 1.5 熔融喷溅 3 2 毫秒激光金属打孔相关理论 4 2.1 固态阶段 4 2.2 熔融阶段 5 2.3 打孔速度 6 2.4 激光加热的时间 9 2.5 打孔深度 9 2.6 计算参数 10 2.7 重力对物质迁移的影响 11 3 计算及讨论 12 3.1 温度与孔深度的关系 12 3.1.1 抛物线形孔 12 3.1.2 实验打出的孔 14 3.2 不同能量激光打孔实验 16 3.3 计算结果与讨论 17 结论 21 (责任编辑：qin) |