摘要
流场速度酒测量和混合过程可视化是流场诊断中的重要内容。然而目前尚无一种合适的技术能够实现这两项参数的同时测量。本文提出了飞秒激光诱导等离子体光谱技术(FLIPS),能够填补这方面诊断的空白。飞秒激光在光学介质中传播时,会形成一条具有一维长度且强度均匀分布的等离子体。这段等离子体可将待测流场中的原子/分子激发到上能级。通过收集上能级原子/分子释放的荧光,并结合光谱分析,能够实现混合分数的测量;通过对不同时刻的长寿命的CN荧光信号进行成像,可实现流场速度的同步测量。FLIPS技术的提出为探究可燃混合气的流动及混合过程,以及二者之间的内在联系提供了有力的技术支持。
Velocity and mixture fraction measurements in combustion flow fields are critical important.However,there is no suitable technique that can achieve simultaneous measurements of these two parameters.In this paper,we developed a novel technique,named femtosecond laser-induced plasma spectroscopy(FLIPS),which can fill in this blank.When femtosecond laser propagates in optical medium,a plasma with a uniform-distributed length will be formed.The clamped intensity of this plasma is enough to excite atoms/molecules to its excited state by means of photolysis or laser-induced photochemical reactions,and then these excited atoms/molecules release fluorescence.The mixture fraction can be measured by collecting and analyzing the plasma emission spectra,and meanwhile,the velocity can be measured by imaging the long-lived CN fluorescence signal at different delay times.FLIPS technique has the advantage of simultaneous measurements of velocity and mixture fraction,and it can provide a powerful technical support for exploring the interrelation of these two parameters.
作者
张大源
高强
李博
李中山
ZHANG Da-Yuan;GAO Qiang;LI Bo;LI Zhong-Shan(State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2020年第6期1544-1549,共6页
Journal of Engineering Thermophysics
基金
国家自然科学基金资助项目(No.91741205,No.51806149)。
关键词
飞秒激光
光谱技术
速度
混合分数
等离子体
femtosecond laser
spectroscopy
velocity
mixture fraction
plasma
