期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2019
卷号：240
期号：3
页码：1-10
DOI：10.1088/1755-1315/240/3/032042
出版社：IOP Publishing
摘要：When predicting the performances of a centrifugal pump by eddy-resolving computational fluid dynamics (CFD) methods such as Large-Eddy Simulation (LES), it is important that the phenomenon of interest and associated flow eddies are accurately computed. Despite recent performance improvement of high-end computers, it is still a challenge to compute a whole multi-stage pump with leakage parts by applying fully-resolved LES and to directly compute active eddies in the turbulent boundary layers, due to grid size requirements. As a part of the analysis of the flows in a multi-stage centrifugal pump by LES, present research focuses on the flow in the pump inter-stage bush. It aims at determining the flow regime, the associated eddies in the bush, and a better understanding of the flow in a grooved inter-stage bush to allow future design optimisations. To assess the existence of the turbulent boundary layer for different Reynolds numbers, focus was placed on the appearance of streamwise vortices which are the smallest active eddies in the turbulent boundary layer. It was observed that these vortices start to develop from Reω=1800 although the velocity profile looks of a laminar boundary layer. Finally, based on CFD results, the effectiveness of the stage bush in terms of minimizing the leakage flow is investigated for the different Reynolds numbers. It is found that the current design shows the maximum effectiveness for Reω=900, and its effectiveness decreases at a higher Reynolds number.
