不同粒径微米/亚微米颗粒布朗运动的实验研究  

Study on the Brownian motion of micro/sub-micro particles with different diameters

作　　者：翟美红 王昊利[1] 赵攀杰 

机构地区：[1]中国计量学院计量测试工程学院

出　　处：《中国计量学院学报》2014年第3期291-295,共5页Journal of China Jiliang University

基　　金：国家自然科学基金资助项目(No.11172287;11272302;10702066)

摘　　要：利用显微粒子追踪测速系统(Micro-PTV)对四种不同粒径(2μm、1μm、0.71μm、0.52μm)的颗粒在纯水中的布朗运动进行了实验研究.使用波长为532nm的连续激光器、电子倍增CCD(EMCCD)相机以及放大倍率为63倍的显微物镜得到颗粒图像.对原始图像进行处理,借助于Video Spot Tracker软件获得相邻两帧图像中示踪颗粒的单步位移,在此基础上计算颗粒在纯水中的实验扩散系数,分别为0.191μm2/s,0.391μm2/s,0.579μm2/s及0.746μm2/s.将计算结果与采用Stokes-Einstein公式计算的无限大空间单个颗粒理论扩散系数进行了比对,偏差在10%以内,实验值略小.实验结果能够正确反映微米(μm)/亚微米颗粒布朗运动的特征.The microscopic particle tracking velocimetry（Miero-PTV） system was used for studying the Brownian motion of micro/sub-micro particles at four different diameters （2 μm, 1 μm, 0.71μm, 0.52 μm） in water. A continuous laser （532 nm）, an electron multiplication CCD （EMCCD） camera and a microscope objective with amplification of 63 × were used to obtain a series of particle images in the experiment, The images were processed in order to gain more clear images. The Video Spot Tracker software was employed to get the single-step displacement of tracer particles in adjacent two images. The diffusion coefficient of four kinds of particles （0. 191 μm2/s, 0. 391 μm2/s,0. 579 μm2/s and 0. 746 μm2/s） were obtained. Compared with theoretical values based on the Stokes-Einstein equation, the deviations of the experiment results from the theoretical values were within 10%; and the experimental value was slightly lower than the theoreticals. The experimental results can reflect the Brownian motion characteristics of micro/sub-micro particles accurately.

关 键 词：布朗运动 微米/亚微米颗粒 显微粒子追踪测速 扩散系数 

分 类 号：O357[理学—流体力学]