摘要
利用透镜聚焦CO2激光击穿空气,在有效解决实验系统时序问题的基础上,借助高速阴影系统研究了3种不同约束构形下激光推进的流场波系结构,获得了波系演化的时序照片,并初步分析了等离子体点火特性和激光支持吸收波(之后退化为激波)的传播速度。结果表明:无约束下流场约呈椭圆形扩散衰减,平面靶和15°扩张靶约束下发生明显的激波反射和边界绕射现象,3种约束中心均出现缓慢变化的低密度高压气团;3种约束下激光支持的爆轰波退化为激波时速度急剧下降,之后激波速度变化平缓,约70～80μs降至声速。
A lens was used to focalize CO2 laser and breakdown air. After the sequential problem of experimental system was solved effectively,wave strctures of laser propulsion flow field under three different constraint conditions were studied with a high-speed shadowing system. Sequential photos of wave evolvement were obtained. The ignition characteristics of laser plasma and the expanding velocity of laser-supported absorption wave （evolved into blast wave） were analyzed primarily. The results indicated that the flow field expanded with a shape of ellipse under no constraint condition,obvious reflection and diffraction of blast wave formed at the edges under constraint conditions of plat target and 15° expanding target,and slowly changed low-density and high-pressure air mass appeared at all three constraints. When laser-supported detonation wave was evolved into blast wave, the expanding velocity dropped sharply under three constraint conditions. After that, the blast wave velocity changed gently and reached sonic one about at 70-80 microsecond.
出处
《光电子．激光》
EI
CAS
CSCD
北大核心
2007年第9期1104-1107,共4页
Journal of Optoelectronics·Laser
基金
国家"973"计划资助项目
自然科学基金资助项目(10672184)
新世纪优秀人才支持计划资助项目
关键词
激光推进
约束
流场
波系结构
点火特性
激波速度
laser propulsion
constraint
flow field
wave structure
ignition characteristics
blast wave velocity
作者简介
文明（1978-），男，湖北武汉人，博士研究生，研究方向为激光推进技术．E-mail：wujiewm@163．com
