纳秒激光烧蚀铝靶羽流流场能量转化过程分析

来源 :推进技术 | 被引量 : 0次 | 上传用户:houjinlei11
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
为研究高能脉冲激光烧蚀铝靶材瞬态流动过程和形成的羽流流场能量转化过程,采用阴影法对纳秒激光烧蚀铝靶羽流膨胀及演化过程进行研究,得到烧蚀流场演化时序图;利用动量守恒方程,建立烧蚀羽流在环境气体中膨胀模型。由实验测量结果,通过对流场参数的无量纲化处理,分析得到烧蚀流场无量纲羽流动能、环境气体动能以及热能之间的能量转化过程。研究表明,初始时刻,由于烧蚀压要远大于环境气压,羽流膨胀与真空中的自由膨胀行为类似,此后,羽流动能逐渐转化为环境气体动能和热能;当无量纲激波半径为1时,羽流的无量纲动能等于被羽流推起的气体的动能,而热能约等于总能量的1/2,最终全部转化为羽流和环境气体热能。 In order to study the transient flow process and the energy conversion process of the plume formed by high energy pulsed laser ablation aluminum target, the shadowing method was used to study the plume expansion and evolution process of aluminum target ablated by nanosecond laser. The ablation flow field Evolution timing diagram; use of momentum conservation equation, the establishment of ablation plume expansion in the ambient gas model. From the experimental results, through the non-dimensional treatment of the flow field parameters, the energy conversion between the non-dimensional plume kinetic energy, ambient gas kinetic energy and thermal energy in the ablation flow field is analyzed. The results show that, at the initial time, the plume flow is gradually transformed into the kinetic and thermal energy of the ambient gas since the ablation pressure is much larger than the atmospheric pressure. The plume expansion is similar to the free expansion in the vacuum. When the dimensionless shock radius is 1 , The non-dimensional kinetic energy of the plume is equal to the kinetic energy of the gas pumped up by the plume, while the heat energy equals about 1/2 of the total energy and eventually all is converted into the plume and the thermal energy of the ambient gas.
其他文献
请下载后查看,本文暂不支持在线获取查看简介。 Please download to view, this article does not support online access to view profile.
当前,我国经济社会发展中需要的高等实用型人才比较缺乏,而我国的高职教育起步较晚,传统的应试教育模式造成职业学校教育毕业生与社会产业、行业和岗位需求不相应,一方面导致
GaN-based blue light emitting diodes(LEDs) have undergone great development in recent years,but the improvement of green LEDs is still in progress.Currently,the
对多股淹没射流作用下的水垫塘二元流动进行了三维全椭圆型紊流数值模拟,并根据实测结果对部分常用紊流模型系数进行了修正。文中分析讨论了多股射流入塘后的水流结构及消能
目的 探讨胃食管斜行套叠吻合法预防吻合口瘘、狭窄和抗返流的效果.方法采用胃食管斜行套叠吻合法,治疗食管贲门癌315例,结合患者术后临床症状、X线钡剂造影及ECT检查评价手术效果.结果全组无吻合口瘘.随机抽样100例行食管胃吻合口X线钡剂造影,1例负角度钡剂返流,余未出现返流征;40例行ECT检查,2例出现自发性返流阳性.随访0.5~1年,均无吞咽困难,无胸骨后烧灼痛.结论本方法吻合安全可靠,预防吻
本文研究了化灌浆液与被灌介质间的相互作用,包括润湿性、亲和力及吸渗性等。提出了多孔介质中的亲和力测试方法,吸渗性及其存在条件。阐述了吸渗性在化灌中的意义和应用。 In
Objective To transfect antisense vector of human cyclooxygenase-2 (COX-2) gene into COX-2 highly expressing chol-angiocarcinoma cell line QBC939 and explore its
职业学校招生困难,说明中职教育还没有得到社会的普遍认可,本文从目前职业教育校企合作的必要性和重要性出发,剖析中职教育校企合作的动因、现状和发展趋势, Vocational sch
去冬以来,衡南县全面推进健康森林、绿色通道、美丽湿地和秀美村庄建设,尤其是在县乡道绿化、珍稀树种造林及秀美村庄建设上取得了一定成效。主要做法是:一、变部门工作为中
本文介绍了大孔隙无砂混凝土透水性的测试方法,给出了不同厚度、不同孔隙率试块在不同水头作用下渗流量测试结果及其经验公式,并对大孔隙无砂混凝土用于集水拦污工作作了可行性