摘要
利用微通道粒子图像测速技术在Re=150时,对断面尺寸为800μm×800μm的两种锯齿型微通道流动进行了研究.采用3μm荧光示踪粒子、10倍显微物镜和14位灰阶CCD相机获得了清晰的粒子图像,通过多幅图像平均的方法消除示踪粒子布朗运动的影响,使用滤光装置提高图像信噪比.对两种锯齿形微通道流动的整场测量发现:微通道内流体在各齿之间流动结构基本一致,尖角和圆角齿形微通道在转弯内侧都存在一个低速旋涡区,圆角齿形微通道旋涡区占据范围相对尖角通道更大;在尖角齿形流道的尖角处,除存在一个完整的大涡外,还发现在大涡上部存在一个与大涡方向相反的叠加涡,叠加涡流动结构不稳定,流速更低,流体中所挟带杂质更容易在该区域沉积形成堵塞,从而导致微流道结构的改变.
With the micro-fluidic particle image velocimetry technique, the flow was measured in both of cusp and fillet jagged micro-channels with a cross section of 800 μm × 800μm at Re= 150. Deionized water with 3 gin-diameter fluorescent particles inside was adopted in the micro-channels. The distinct images were obtained with a 10-fold microscope and 14-bit CCD camera system. The influence of Brownian motion was eliminated by averaging obtained images of the particles. Filter lens were used to improve the signal-to-noise ratio of the images. The experimental results indicate that the flow patterns in both jagged micro-channels are similar to each other. There is a low velocity vortex cavity at the swerving inside for both the fillet jagged micro-channel and the cusp jagged micro-channel, and the former vortex cavity is greater than the latter one. Moreover, at the jag peak of the cusp jagged micro-channel, there exist a big intact vortex and a superposition vortex in the opposite direction with lower velocity and unsteady structure. The impure substance in the low-velocity region is easier to deposit and form block, leading to the structure change of the micro-channels.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2009年第9期109-113,共5页
Journal of Xi'an Jiaotong University
基金
国家科技攻关"十五"计划专项经费资助项目(2004BA901A21)
