The stall in a centrifugal pump impeller under a quarter-load condition is investigated by using a third-order SGS model named the DCNM, for a better understanding of the rotation effect on the stall phenomenon. The s...The stall in a centrifugal pump impeller under a quarter-load condition is investigated by using a third-order SGS model named the DCNM, for a better understanding of the rotation effect on the stall phenomenon. The study of the distributions of the Reynolds stresses, the production tei*m and the rotation term reveals that the production and the rotation jointly result in the non-uniform Reynolds stress distribution. Further study of the two components of the production and the rotation shows that they jointly transport a certain energy from the Reynolds component R、to Ruu.展开更多
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 differ...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.展开更多
基金Project supported by the Key program of the Ministry of Education (Grant No. 113010A)the National Natural Science Foundation of China (Grant No. 51209206).
文摘The stall in a centrifugal pump impeller under a quarter-load condition is investigated by using a third-order SGS model named the DCNM, for a better understanding of the rotation effect on the stall phenomenon. The study of the distributions of the Reynolds stresses, the production tei*m and the rotation term reveals that the production and the rotation jointly result in the non-uniform Reynolds stress distribution. Further study of the two components of the production and the rotation shows that they jointly transport a certain energy from the Reynolds component R、to Ruu.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51679240,5217090424 and 51809268).
文摘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.
