三角孔多孔板下游空化流场的PIV剖析  

PIV analysis of cavitating water flows behind triangular multiorifice plates

作　　者：张凯 董志勇 赵文倩 居文杰 李杨如 耿坤 秦兆雨 王磊 ZHANG Kai DONG Zhiyong ZHAO Wenqian JU Wenjie LI Yangru GENG Kun QIN Zhaoyu WANG Lei(Research Institute of Hydraulic and Municipal Engineering, Zhejiang University of Technology, Hangzhou 310014)

机构地区：[1]浙江工业大学水利与市政工程研究所,杭州310014

出　　处：《水力发电学报》2017年第10期56-64,共9页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金(51479177)

摘　　要：采用粒子图像测速仪(PIV)对不同类型的三角形孔口多孔板下游空化流场的流动特性进行了量测,分析了孔口大小(边长a=2.6 mm,4.0 mm,5.1 mm和6.7 mm)、孔口数量(n=9,16,25和64)和孔口排列(棋盘式和交错式)对多孔板下游时均流速、紊动强度及紊动切应力分布的影响。结果表明,多孔板下游的时均流速、紊动强度及紊动切应力呈现不同程度的锯齿状分布,适当地缩小孔口、增加孔口数量,并将孔口布置为交错式排列有利于多孔板下游水流的掺混、紊动和剪切作用;在试验设计的不同规格三角形孔口多孔板中,孔口边长a=4.0 mm、孔口数量n=25且孔口为交错式排列的多孔板下游空化流场的流速梯度最大、紊动剪切作用最为剧烈。A particle image velocimetry （PIV） was used to measure the water flows behind triangular multi-orifice plates of five different types, and an analysis was made on the effects of different orifice sizes （side length a = 2.6, 4.0, 5.1 and 6.7 mm）, orifice numbers （n = 9, 16, 25 and 64） and orifice arrangements （checkboard and staggered） on time-averaged velocity, turbulence intensity, and turbulent shear stress of the flows. Results showed that the cross-sectional profiles of these flow quantities took a zigzag shape, and that the turbulence mixing and shearing of the multiple-jet flows behind the plates could be intensified and even flow cavitation could be generated by appropriately decreasing the orifice size, increasing the number of orifices, or taking staggered arrangement. The strongest intensification in all the test cases occurred at the staggered arrangement of 25 triangular orifices with their side length of 4mm, achieving the greatest velocity gradient and most intense mixing and shearing effects.

关 键 词：水力空化 三角形孔口多孔板 PIV 时均流速 紊动强度 紊动切应力 

分 类 号：TV131.34[水利工程—水力学及河流动力学]