摘要
采用微流动粒子图像测速技术Micro-PIV对0.4-0.8 mm的方形截面微通道流场进行了研究.实验选取3μm的荧光染色微球作为示踪粒子,使用532 nm激光、12位灰阶电荷耦合器件（CCD）相机及10倍显微物镜得到粒子图像.通过背景噪声处理技术提高了图像信噪比,并采用系综相关及回归算法得到了微通道截面的速度分布,测量的空间分辨率达到23.68μm×23.68μm×15.64μm.为了消除壁面随机粗糙分布的影响,采用沿流向进行空间平均方法得到了充分发展的方形截面微通道速度分布.将测量结果与方形截面理论幂函数速度廓线进行比较发现：微通道近壁区流场受到扰动的强弱和流道尺寸直接相关,除近壁区外的大部分区域速度分布与矩形截面流道理论速度分布符合良好.
Micro-PIV measurements were implemented for laminar flows in 0.4 - 0.8 mm microchannels under different conditions. In the measurements, 3 μm fluorescent microspheres were chosen as the track particles, whose images were gained by using 532 nm laser, 12 bit CCD and 10X objective. The process techniques of background noise were employed to improve SNR of images. The velocity vectors at the middle section of microchannels were achieved by the ensemble correlation and recursive arithmetics, and spatial resolving power of measurements reached 23.68 μm × 23.68 μm × 15. 64 μm. The characteristics of velocity fields were analyzed by illustrating the space-averaged streamwise velocities in whole fields. The comparison of the averaged velocity with theoretical velocity profiles shows that velocity distributions are in accordance with their theoretical counterparts. In order to remove the stochastic distribution effects of wall surfaces, the fully-developed velocity distributions were determined by space-averaged method, along the streamwise direction for the whole velocity field. Compared with the theoretical power function profile of velocity distributions in the square channels, the flow for the Micro-PIV measurements has the characteristics that the disturbances of velocity at the region near the walls have direct correlations with the scales of the microchannels. Execpt the areas near the walls, the space-averaged velocities are in agreement with the theoretical velocity profile.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2007年第11期1355-1359,共5页
Journal of Xi'an Jiaotong University
基金
教育部高等学校博士学科点专项科研基金资助项目(20030698004)
国家西部开发重大科技行动资助项目(2004BA901A21)
新疆自治区"十五"攻关重大项目资助(200433121)
