Flow Visualization & Measurement of Two-dimensional Temperature Field in the Rarefied Gas Flow Using LIF (Laser Induced Fluoresence)

流动可视化

• 批准号: 02650131
• 负责人: NIIMI Tomohide
• 金额: $ 1.28万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650131/
• 关键词: LIF; Iodine Molecule; Temperature Measurement; Two-dimensional Measurement; Visualized Image; High Sensitive Vidicon Camera; Laser Sheet; Picture Processing; 高感度ビジコンカメラ

A method for quantitative imaging for temperature in the rarefied gas flow has been developed. The flow field is visualized by planar laser-induced fluorescence (PLIF) of iodine molecules seeded in carrier gas. Iodine molecules have many absorption lines in visible region and radiate intense fluorescence. The fluorescence intensity is proportional to the number of molecules in the energy level excited by the laser beam. From the dependence of this number on the temperature, the local temperature can be decided from the ratio of the fluorescence intensities of two visualized images which are obtained by irradiations of laser beams with different wave length. This method allows to image the two-dimensional temperature distribution of the flow field by means of a laser sheet and a high sensitive vidicon camera. This method is applied to the temperature measurement of the flow field of a su personic free jet in which temperature varies drastically. It is found that the temperature distribution of the jet measured by P(16)/R(18) [514.720 nm] and P(26)/R(28) [514.942 nm] absorption lines in the transition of B(v'=43) X(v"=0) agrees well the theoretical one.

开发了一种稀薄气流温度定量成像方法。通过载气中接种的碘分子的平面激光诱导荧光 (PLIF) 使流场可视化。碘分子在可见光区有许多吸收线并辐射出强烈的荧光。荧光强度与激光束激发的能级中的分子数量成正比。根据该数字对温度的依赖性，可以根据通过不同波长的激光束照射获得的两个可视化图像的荧光强度的比率来确定局部温度。该方法允许通过激光片和高灵敏度摄像机对流场的二维温度分布进行成像。该方法适用于温度变化剧烈的超音速自由射流流场的温度测量。发现在 B(v'= 43) X(v"=0) 与理论值非常吻合。