Experimental Study on the Classification and Evolution of the Tip Cavitation Morphology in Axial Waterjet Pumps with Two Different Blade Numbers

Tip leakage flow and induced unstable cavitation can significantly damage the performance of axial waterjet pumps. This study investigated the impact of blade numbers on cavitating conditions in an axial waterjet pump by conducting tests of performance characteristics and high-speed photography expe...

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Main Authors: Xi Shen, Haoran Wu, Gang Yang, Rui Tang, Chenxin Chang, Bin Xu, Suben Lin, Desheng Zhang
Format: Article
Language:English
Published: MDPI AG 2024-10-01
Series:Journal of Marine Science and Engineering
Subjects:
Online Access:https://www.mdpi.com/2077-1312/12/11/1898
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author Xi Shen
Haoran Wu
Gang Yang
Rui Tang
Chenxin Chang
Bin Xu
Suben Lin
Desheng Zhang
author_facet Xi Shen
Haoran Wu
Gang Yang
Rui Tang
Chenxin Chang
Bin Xu
Suben Lin
Desheng Zhang
author_sort Xi Shen
collection DOAJ
description Tip leakage flow and induced unstable cavitation can significantly damage the performance of axial waterjet pumps. This study investigated the impact of blade numbers on cavitating conditions in an axial waterjet pump by conducting tests of performance characteristics and high-speed photography experiments on three-blade and four-blade impellers. The results showed that the critical cavitation number <i>σ</i><sub>c</sub> of the three-blade impeller was larger, while the four-blade impeller flow pattern deteriorated more rapidly after <i>σ</i><sub>c</sub>. Various cavitation structures in the tip region were observed under different conditions, including clearance cavitation, shear layer cavitation, tip leakage vortex cavitation, and suction-side-perpendicular cavitating vortices (SSPCVs). Tip cavitation maps of the test impellers were drawn based on the flow rate coefficient and cavitation number variation. The three-blade impeller exhibited a wider range of severe cavitation, particularly with an increased occurrence of SSPCVs. With the cavitation number and flow rate coefficient decreased, the SSPCV generated from triangular cavitation cloud shedding presented an increased trend in scale and quantity. Conversely, in the case of the four-blade impeller, SSPCVs were often disrupted by the adjacent blade during migration and interfered with the tip cavitation in the neighboring flow passage.
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id doaj-art-df23696ba3ba49a987bbaeadbecabb19
institution DOAJ
issn 2077-1312
language English
publishDate 2024-10-01
publisher MDPI AG
record_format Article
series Journal of Marine Science and Engineering
spelling doaj-art-df23696ba3ba49a987bbaeadbecabb192025-08-20T02:48:02ZengMDPI AGJournal of Marine Science and Engineering2077-13122024-10-011211189810.3390/jmse12111898Experimental Study on the Classification and Evolution of the Tip Cavitation Morphology in Axial Waterjet Pumps with Two Different Blade NumbersXi Shen0Haoran Wu1Gang Yang2Rui Tang3Chenxin Chang4Bin Xu5Suben Lin6Desheng Zhang7Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013, ChinaResearch Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013, ChinaResearch Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013, ChinaResearch Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013, ChinaResearch Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013, ChinaResearch Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013, ChinaHengfengtai Precision Machinery Co., Ltd., Wenzhou 325000, ChinaResearch Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013, ChinaTip leakage flow and induced unstable cavitation can significantly damage the performance of axial waterjet pumps. This study investigated the impact of blade numbers on cavitating conditions in an axial waterjet pump by conducting tests of performance characteristics and high-speed photography experiments on three-blade and four-blade impellers. The results showed that the critical cavitation number <i>σ</i><sub>c</sub> of the three-blade impeller was larger, while the four-blade impeller flow pattern deteriorated more rapidly after <i>σ</i><sub>c</sub>. Various cavitation structures in the tip region were observed under different conditions, including clearance cavitation, shear layer cavitation, tip leakage vortex cavitation, and suction-side-perpendicular cavitating vortices (SSPCVs). Tip cavitation maps of the test impellers were drawn based on the flow rate coefficient and cavitation number variation. The three-blade impeller exhibited a wider range of severe cavitation, particularly with an increased occurrence of SSPCVs. With the cavitation number and flow rate coefficient decreased, the SSPCV generated from triangular cavitation cloud shedding presented an increased trend in scale and quantity. Conversely, in the case of the four-blade impeller, SSPCVs were often disrupted by the adjacent blade during migration and interfered with the tip cavitation in the neighboring flow passage.https://www.mdpi.com/2077-1312/12/11/1898axial waterjet pumptip leakage flowunsteady cavitationtip cavitation mapsuction-side-perpendicular cavitating vortices
spellingShingle Xi Shen
Haoran Wu
Gang Yang
Rui Tang
Chenxin Chang
Bin Xu
Suben Lin
Desheng Zhang
Experimental Study on the Classification and Evolution of the Tip Cavitation Morphology in Axial Waterjet Pumps with Two Different Blade Numbers
Journal of Marine Science and Engineering
axial waterjet pump
tip leakage flow
unsteady cavitation
tip cavitation map
suction-side-perpendicular cavitating vortices
title Experimental Study on the Classification and Evolution of the Tip Cavitation Morphology in Axial Waterjet Pumps with Two Different Blade Numbers
title_full Experimental Study on the Classification and Evolution of the Tip Cavitation Morphology in Axial Waterjet Pumps with Two Different Blade Numbers
title_fullStr Experimental Study on the Classification and Evolution of the Tip Cavitation Morphology in Axial Waterjet Pumps with Two Different Blade Numbers
title_full_unstemmed Experimental Study on the Classification and Evolution of the Tip Cavitation Morphology in Axial Waterjet Pumps with Two Different Blade Numbers
title_short Experimental Study on the Classification and Evolution of the Tip Cavitation Morphology in Axial Waterjet Pumps with Two Different Blade Numbers
title_sort experimental study on the classification and evolution of the tip cavitation morphology in axial waterjet pumps with two different blade numbers
topic axial waterjet pump
tip leakage flow
unsteady cavitation
tip cavitation map
suction-side-perpendicular cavitating vortices
url https://www.mdpi.com/2077-1312/12/11/1898
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