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Simultaneous Measurements of Flow and Temperature Fields by Laser Induced Fluorescence and Correlation Techniques

通过激光诱导荧光和相关技术同时测量流场和温度场

基本信息

批准号：
04555050
负责人：
MAEDA Masanobu
金额：
$ 3.39万
依托单位：
KEIO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

An image processing velocimeter and thermometer using the Digital Particle Image Velocimetry (DPIV) and the Laser Induced Fluorescence (LIF) technique has been applied to measurements of a thermally stratified pipe flow and an impinging jet. The velocity and temperature data measured by the system were transferred to an EWS and analyzed by a visualization software. The results reveal the mechansm of the turbulent mixing and the turbulent heat transfer.Two-dimensional time-dependent velocity and temperature fields of a stable thermally stratified pipe flow was measured by using a DPIV and LIF to capture the instantaneous structure of turbulent mixing accompanied by the heat and momentum transfer. One thousand instantaneous velocity and temperature distributions were obtained successively. The vorticity, Reynolds stress and heat flux vectors were estimated. The instantaneous distribution of the heat vectors and temporal variations of the Reynolds stress showed the strong exchange of heat and momentum occur through the coherent structure.Velocity and temperature in the stagnation region of a plane impinging jet were simultaneously measured by DPIV and LIF.Instantaneous thermal flow field and spatial correlation of the vorticity and turbulent heat flux showed that a streamwise vortex pair in the stagnation region swept cold fluid toward the wall and ejected high-temperature fluid toward the outer region. The weighted PDF of the turbulent heat flux indicated that the free-jet region and the vorticity was amplified by the mean strain in the vicinity the wall.

采用数字粒子图像测速仪（DPIV）和激光诱导荧光（LIF）技术的图像处理测速仪和温度计已被应用于热分层管流和撞击射流的测量。系统测量的速度和温度数据被传送到EWS，并通过可视化软件进行分析。研究结果揭示了紊流混合和紊流换热的机理。利用DPIV和LIF测量了稳定热分层管道流动的二维随时间变化的速度场和温度场，以捕捉伴随热动量传递的湍流混合的瞬时结构。先后得到了1000个瞬时速度和温度分布。估算了涡量、雷诺应力和热流通量矢量。热矢量的瞬时分布和雷诺应力的时间变化表明，在相干结构中发生了强烈的热动量交换。用DPIV和LIF同时测量了飞机撞击射流滞止区速度和温度。瞬时热流场及涡度和湍流热通量的空间相关性表明，滞止区存在向流涡对，将冷流体向壁面扫去，将高温流体向外喷射。湍流热通量的加权PDF表明，壁面附近的平均应变放大了自由射流区域和涡度。