Three-dimensional measurement and visualization of internal flow of a moving droplet using confocal micro-PIV
Three-dimensional measurement and visualization of internal flow of a moving droplet using confocal micro-PIV
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DOI：
10.1039/b617391h
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发表时间：
2007-01-01
期刊：
影响因子：
6.1
通讯作者：
Oshima, Marie
中科院分区：
文献类型：
--
作者：
Kinoshita, Haruyuki;Kaneda, Shohei;Oshima, Marie
本文介绍了一种微流场诊断技术--高速共焦显微粒子图像测速技术（PIV测速）及其在微通道内液滴流动测量中的应用。将高速共焦扫描仪与常规显微PIV技术相结合，成功地构建了一套共焦显微PIV系统。共焦显微PIV系统使我们能够在2000帧/秒（-1）下获得一系列清晰和高对比度的横截面粒子图像。本文研究了共焦显微PIV中决定离面测量分辨率的重要参数--共焦深度。利用该共焦显微PIV系统，我们可以在228 mm × 6171 μ m的区域内测量微流场的速度分布，共焦深度为1.88 μ m。提出了一种基于共焦显微PIV和连续性方程的三维速度测量方法。这种方法使我们能够测量三个速度分量在三维域的微流。将共焦显微PIV系统应用于液滴内部流动的测量。我们测量了液滴在100 μ m（宽）× 58 μ m（深）通道中运动的三分量速度的三维分布。利用共焦显微PIV技术获得了液滴内部的体积速度分布，研究了液滴内部的三维流动结构。测量结果表明，液滴内部形成了三维复杂的循环流动。
This paper presents a micro-flow diagnostic technique, 'high-speed confocal micro-particle image velocimetry (PIV)', and its application to the internal flow measurement of a droplet passing through a microchannel. A confocal micro-PIV system has been successfully constructed wherein a high-speed confocal scanner is combined with the conventional micro-PIV technique. The confocal micro-PIV system enables us to obtain a sequence of sharp and high-contrast cross-sectional particle images at 2000 frames s(-1). This study investigates the confocal depth, which is a significant parameter to determine the out-of-plane measurement resolution in confocal micro-PIV. Using the present confocal micro-PIV system, we can measure velocity distributions of micro-flows in a 228 mm 6 171 mu m region with a confocal depth of 1.88 mu m. We also propose a three-dimensional velocity measurement method based on the confocal micro-PIV and the equation of continuity. This method enables us to measure three velocity components in a three-dimensional domain of micro flows. The confocal micro-PIV system is applied to the internal flow measurement of a droplet. We have measured three-dimensional distributions of three-component velocities of a droplet traveling in a 100 mu m ( width) x 58 mu m ( depth) channel. A volumetric velocity distribution inside a droplet is obtained by the confocal micro-PIV and the three-dimensional flow structure inside the droplet is investigated. The measurement results suggest that a three-dimensional and complex circulating flow is formed inside the droplet.