利用PIV测试系统对自行设计的管道流动实验装置进行实验研究,考察了矩形壁面微结构对管道流动阻力的影响及其内在的机理.测试实验了三种矩形壁面微结构,槽宽均为s＝1. 0mm,槽深分别为h＝0. 3mm、0. 5mm、0. 7mm.实验介质为蒸馏水,管内流体流速范围在0. 2m·s-1到1. 6m·s-1之间,实验管段处于水平.实验结果表明:矩形沟槽的管道压降与槽深h有一定关系,与无量纲槽宽s+有更直接的关系;在一定范围的雷诺数下矩形沟槽管道压降比同工况下光滑平板管道压降要小,此时矩形沟槽具有减阻效果;矩形沟槽结构在无量纲化槽宽10＜s+＜22情况下具有减阻效果,且槽深h越小,减阻范围越大,最大减阻率越小;比较光滑平板平均速度分布,矩形沟槽使边界层增厚,流向与法向速度均方根速度减小,流向与法向速度脉动减弱、雷诺应力减小,从而达到减小阻力的目的.%The experimental design of the pipeline flow experiment device designed by ourselves was carried out using the PIV test system. The influence of the rectangular wall microstructure on the flow resistance of the pipeline and its intrinsic mechanism were investigated. Three kinds of rectangular wall microstructures were tested and tested. The groove width was s＝1. 0 mm,and the groove depths were h＝0. 3 mm,0. 5 mm,and 0. 7 mm,respectively. The experimental medium is distilled water,the flow rate of the fluid in the tube is in the range of 0. 2m·s-1to 1. 6m·s-1,and the experimental tube section is at the level. The experimental re-sults show that the pressure drop of the pipe in the rectangular groove has a certain relationship with the groove depth h,and has a more direct relationship with the non-dimensional groove width s+;under a certain range of Reynolds number,the pressure drop rati-o of the rectangular groove pipe is smooth under the same conditions. Flat pipe pressure drop should be small,at this time the rec-tangular groove has a drag reduction effect;rectangular groove structure in the dimensionless groove width of 10＜s +＜22 under the drag reduction effect,and the smaller the groove depth h,the more drag reduction range Larger,the smaller the maximum drag re- duction rate;compared with the smooth plate average velocity distribution,the rectangular trench thickens the boundary layer,the root mean square velocity of the flow and normal velocity decreases,the flow direction and normal velocity pulsation weaken,and the Reynolds stress decreases,to achieve the purpose of reducing resistance.
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