流体绕流微柱群的Micro-PIV实验研究

微柱群通道内的流动特性是设计与优化其散热结构的基础。采用显微粒子测速技术（Micro-PIV）对绕流微柱群流动进行研究，测定了不同Re下的绕流流场，分析了绕流微柱群的速度场以及Re对涡结构及回流长度的影响。结果表明，随着Re的增大，微圆柱尾流区出现涡结构，回流长度逐渐增大，微尺度下柱体绕流过程中边界层分离现象相对于宏观尺度具有一定的滞后性。

Experimental study on flow past micro-cylinder-groups by Micro-PIV method

The micro-cylinder-group is an efficient heat dissipation structure, which has great application prospects for solving the cooling problems in micro space. The flow characteristics in the channel with micro-cylinder-group are the foundation for the design and optimization of the heat dissipation structure. Micro particle image velocimetry (Micro-PIV) was used to study the flow past the micro-cylinder-group and the flow field around micro-cylinders with different Reynolds numbers was measured. The velocity field of the micro-cylinder-group and the effects of Reynolds number on the vortex structure and the backflow length were analyzed. The results show that vortex structure appears in the wake region of micro-cylinder and the backflow length increases gradually with the increase of Reynolds number. The boundary layer separation phenomenon in flow past the micro-cylinder has a certain lag compared with the macro-scale.