Investigation on the stall types in impellers with different blade numbers  

作　　者：Xiao-dong Liu Yao-jun Li Zhu-qing Liu Wei Yang 

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

出　　处：《Journal of Hydrodynamics》2023年第2期299-313,共15页水动力学研究与进展B辑（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.51679240,5217090424 and 51809268).

摘　　要：Stall is a complex flow phenomenon and its existence usually shows significant differences in different impeller forms.In this paper,the flow field characteristics and mechanism of stall types in impellers with different blade numbers were studied through the combination of experiment and numerical simulation at stall inception stage.In the experiments,it was observed that the five-blade impeller entered the rotating stall stage from a relatively stable flow field within a small flow rate interval.For the six-blade impeller,the root cause that stall vortices appeared in channels alternately rather than each one evenly was also reasonably explained.The validated numerical simulation method was utilized to reveal the three-dimensional flow field in impeller channels.The results indicate the swirling vortex near the impeller shroud was periodically sucked in and escaped from region near the blade suction side,which was the fundamental driving force of rotating stall.The sudden change of flow field caused by the fusion of the separation vortex at the channel inlet and the vortex induced by the swirling vortex near shroud is the essential reason for the formation of alternating stall.What’s more,the stall inception flow field is clearly defined in impellers,which is of great significance for the further analysis of stall characteristics.Based on the distribution characteristics of vortex structure near impeller shroud with different blade numbers at different flow rate conditions,this paper deeply investigated the formation mechanism of different stall types in impellers.

关 键 词：Numerical simulation high-frequency particle image velocimetry(PIV) IMPELLERS swirling vortex stall type 

分 类 号：O35[理学—流体力学]