圆形截面管路内PIV流场测量的直接校正方法

为修正圆形截面管路内PIV（粒子图像测速）流场测量中的图像畸变，建立了一种基于光学原理的直接数值校正方法.该方法不受流体饱和温度限制，可对坐标和速度矢量进行同步校正，壁面附近的光学畸变也能够进行较好还原，同时不需要额外的辅助设备.采用Fortran语言编制了通用的计算机代码，只需改变程序相关输入参数，即可应用于其他条件下的图像校正.使用方形规则化网格对其进行了验证，误差不超过3%.对于双层圆形管壁内低温气液两相流动的PIV流场测量实验，该方法能够给出满意的校正结果.

Direct Image Correction Algorithm for PIV Measurement of Flowfield within Circular Tube

A direct image correction algorithm based on the optical principle was developed to solve flowfield distortion of particle image velocimetry(PIV) measurement within circular tube. Without the restriction of liquid saturation temperature, this method can be applied for the synchronous correction of coordinate and velocity vector, and can correctly recover the image distortion in the vicinity of tube wall. In addition, this method requires no accessorial device. A computer code was developed based on Fortran language, which can be easily applied to other cases as long as changing the relevant input parameters. The method was validated by using a uniform square grid with the max deviation of 3%. And this method can provide a satisfactory correction result for the PIV experiment of cryogenic gas liquid two phase flow.