Investigation on subsurface vortices within a closed pump intake under different pressure conditions  

作　　者：Miao Guo Xue-lin Tang Xiao-qin Li Fu-jun Wang Xiao-yan Shi 

机构地区：[1]College of Water Resources and Civil Engineering,China Agricultural University,Beijing 100083,China [2]Beijing Engineering Research Centre of Safety and Energy Saving Technology for Water Supply Network System,China Agricultural University,Beijing 100083,China

出　　处：《Journal of Hydrodynamics》2020年第5期914-928,共15页水动力学研究与进展B辑（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.51479196,51779257);the National Natural Science Foundation for the Youth of China(Grant No.51909132).

摘　　要：An experimental study to investigate various features of subsurface vortices and their evolutions inside a closed pump intake under different pressure conditions at free surface,and to analyze the influence of a pipe bell with different mean axial velocities at the same water level on flow patterns is presented.For all cases,three different flow regimes are closely observed:various side-wall attached,back-wall attached and submerged vortices structures,and their evolutions are subject to the free-surface pressure for a critical flow rate,the number and strength of all these vortex rise as the absolute value of the pressure increases for a higher flow rate,for a lower flow rate,whether the side-wall vortices occur or not is related closely to the pressure magnitude,and there are no vortices for lower absolute pressure values,the number and the strength of the side-wall vortices increase as the absolute pressure values increase.Besides,based on statistical analyses,the side-wall vortex probability on the right side along the stream-wise direction is much higher than that on the opposite side for all operation cases,particularly single vortex probability,and the back-wall vortex probabilities are quite higher with values of more than 90%,meanwhile,the multi-vortices probability is much higher than that of the single-vortex.The captured vortices have been qualitatively classified into different“vortex zones”:no vortex zones and vortex zones including transition,single-and multi-vortex.The Reynolds number and the absolute value pressure are the most important parameters which influence the existence and the number of these vortices,and the increase of the two parameters reduces the no vortex transition zone and causes bigger difference in the back-wall and side-wall vortex zones.

关 键 词：Evolution of subsurface vortices particle-image velocimetry(PIV) vortex probability closed pump intake 

分 类 号：O35[理学—流体力学]