高焓流场氧原子激光诱导荧光技术初步研究

发布时间：2018-07-30 08:29

【摘要】：基于双光子吸收激光诱导荧光(TALIF)技术,在纯净的高焓流场环境中,将脉冲激光从垂直于流场方向射入流场,并通过布置在风洞试验段外与流场和激光形成的平面向垂直方向上的ICCD测量获取到了二维氧原子的荧光信号,该信号可以反映氧原子相对浓度。为保证实验中使用到的激发激光波长为最佳激发波长,分别对氧原子基态处在不同角量子数的情况进行了测试,最终确定J=2时,波长为225.584nm为最终实验激发波长,为了保证所获取的氧原子荧光信号在非饱和线性区,在同种状态下,将激发激光能量从小到大调整并进行荧光信号的测试,获取了激光能量在3.4mJ以下的线性区域。为确保获取清晰对比度最优的ICCD荧光图像,选择了Nikon f=105mm F/2.8镜头为实验测试镜头,同时将50次曝光的累计结果作为图像输出。对所获取的荧光图像进行分析,实验结果可以清晰地看到超声速流场中压缩波形成的距中心线约±50mm位置处左右各一个的小峰,亚声速流场中中心处氧原子浓度有一个约60mm宽的均匀区域,区域以外氧原子浓度急剧下降,这些结果符合实验风洞特性,此测试方法可以很好地运用到流场测量中。
[Abstract]:Based on the two-photon absorption laser induced fluorescence (TALIF) technology, the pulsed laser is shot from the flow field perpendicular to the flow field in a pure high enthalpy flow field, and the fluorescence signal of the two-dimensional oxygen atom is obtained by the ICCD measurements arranged in the vertical direction of the flow field and the laser formed in the wind tunnel test section. The signal can be obtained. To reflect the relative concentration of oxygen atoms, in order to ensure that the wavelength of the excited laser used in the experiment is the best excitation wavelength, the oxygen atom ground state is at different angular quantum numbers respectively. When the J=2 is finally determined, the wavelength is 225.584nm as the final experimental excitation wavelength, in order to guarantee the obtained oxygen atom fluorescence signal in the unsaturated linearity. In the same state, the excitation laser energy is adjusted from small to large and the fluorescence signal is tested. The linear region of the laser energy below 3.4mJ is obtained. The Nikon f=105mm F/2.8 lens is selected as the experimental test lens to ensure the best clear contrast of the ICCD fluorescence image, and the cumulative results of the 50 exposure are taken as the results. Image output. The obtained fluorescence image is analyzed. The experimental results can clearly see the small peaks around the center line about the center line about 50mm in the supersonic flow field. The oxygen atom concentration at the center of the subsonic flow has a uniform region of about 60mm wide, and the oxygen concentration outside the region drops sharply. These results conform to the experimental wind tunnel characteristics. This test method can be well applied to the flow field measurement.
【作者单位】：四川大学原子与分子物理研究所;中国空气动力研究与发展中心超高速空气动力研究所;
【基金】：部级科研基金项目(9140A13020315KG29036)资助
【分类号】：O657.3

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