微管道内湍流转捩的实验研究  

EXPERIMENTAL STUDY OF TRANSITIONAL AND TURBULENT FLOW IN A MICROTUBE

作　　者：郝鹏飞[1] 何枫[1] 朱克勤[1] 

机构地区：[1]清华大学航天航空学院,北京100084

出　　处：《工程力学》2006年第A01期30-34,共5页Engineering Mechanics

基　　金：国家自然科学基金资助项目(10272066)

摘　　要：研究旨在确定微管道内流动从层流到湍流转捩的临界雷诺数。利用微观粒子图像测速技术（Micro-PIV）研究了去离子水在内径为230gm的圆形截面玻璃微管道内的流场结构，得到了从层流到充分发展湍流各流动状态下的轴向平均速度分布和湍流度分布，实验雷诺数为1020～3145，同时研究了微管道内的流动阻力特性。平均速度场和脉动速度场的实验结果表明微管道内从层流到湍流的转捩发生在Re=1800～1900左右，与流动阻力的测量结果一致，与宏观流动比较，并未发现微管道内的流动转捩有明显提前。实验结果还显示，当Re〉2700时，微管道内的平均流速分布和相对湍流度分布呈现典型的充分发展湍流状态特征。This research is aimed at determining the critical Reynolds number of the transition from laminar flow to turbulent in the microtube. The global pressure drop and velocity field were experimentally investigated for water flow in a glass microtube with a hydraulic diameter of 230μm and Reynolds numbers between 1020 and 3140. The axial mean velocity profiles and turbulent intensities obtained from Microscopic particle image velocimetry （micro-PIV） show that the transition from laminar flow to turbulent flow occurred for Reynolds number ranging between 1800 and 1900. This result is consistent with the global measurements of the pressure drop, and no obvious early transition to turbulence in the microtube is observed compared with the experimental data in the macro scale pipe flow. The experimental data of flow fields also suggest the flow was fully developed turbulent for Re〉2660.

关 键 词：流体力学 湍流 微观粒子图像测速系统(Micro-PIV) 微管道 转捩 

分 类 号：O354.1[理学—流体力学]