Study on a horizontal axial flow pump during runaway process with bidirectional operating conditions

Abstract The ultra-low head pump stations often have bidirectional demand of water delivery, so there is a risk of runaway accident occurring in both conditions. To analyze the difference of the runaway process under forward runaway condition (FRC) and backward runaway condition (BRC), the whole flo...

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Autores principales:	Kan Kan, Qingying Zhang, Zhe Xu, Huixiang Chen, Yuan Zheng, Daqing Zhou, Maxima Binama
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/7ab45e30cadf43b192c6c2e29efed217
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spelling	oai:doaj.org-article:7ab45e30cadf43b192c6c2e29efed2172021-11-14T12:21:33ZStudy on a horizontal axial flow pump during runaway process with bidirectional operating conditions10.1038/s41598-021-01250-12045-2322https://doaj.org/article/7ab45e30cadf43b192c6c2e29efed2172021-11-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-01250-1https://doaj.org/toc/2045-2322Abstract The ultra-low head pump stations often have bidirectional demand of water delivery, so there is a risk of runaway accident occurring in both conditions. To analyze the difference of the runaway process under forward runaway condition (FRC) and backward runaway condition (BRC), the whole flow system of a horizontal axial flow pump is considered. The Shear-Stress Transport (SST) k–ω model is adopted and the volume of fluid (VOF) model is applied to simulate the water surface in the reservoirs. Meanwhile, the torque balance equation is introduced to obtain the real time rotational speed, then the bidirectional runaway process of the pump with the same head is simulated. In addition, the vortex transport equation and swirl number are proposed to reveal the flow characteristics during the runaway process. The results show that the runaway process can be divided into five stages: the drop, braking, rising, convergence and runaway stages, according to the changing law of torque curve. In the rising stage, the pressure difference on the blade surface continues to increase, which contributes to the abnormal torque increase. In this stage, the flow hits the pressure surface (PS) at a faster speed enlarging the pressure on PS, and the flow separation takes place on the suction surface (SS) weakening the pressure on SS. During the convergence and runaway stage, the pulsation amplitude of torque and axial force under FRC is obviously larger than those under BRC. This is because the rotation frequency of the vortex rope is the same as main pressure fluctuation frequency in impeller under FRC, which enhances the pulsation amplitude. Whereas the vortices are broken due to the inhibitive effect from guide vanes under BRC.Kan KanQingying ZhangZhe XuHuixiang ChenYuan ZhengDaqing ZhouMaxima BinamaNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-21 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Kan Kan Qingying Zhang Zhe Xu Huixiang Chen Yuan Zheng Daqing Zhou Maxima Binama Study on a horizontal axial flow pump during runaway process with bidirectional operating conditions
description	Abstract The ultra-low head pump stations often have bidirectional demand of water delivery, so there is a risk of runaway accident occurring in both conditions. To analyze the difference of the runaway process under forward runaway condition (FRC) and backward runaway condition (BRC), the whole flow system of a horizontal axial flow pump is considered. The Shear-Stress Transport (SST) k–ω model is adopted and the volume of fluid (VOF) model is applied to simulate the water surface in the reservoirs. Meanwhile, the torque balance equation is introduced to obtain the real time rotational speed, then the bidirectional runaway process of the pump with the same head is simulated. In addition, the vortex transport equation and swirl number are proposed to reveal the flow characteristics during the runaway process. The results show that the runaway process can be divided into five stages: the drop, braking, rising, convergence and runaway stages, according to the changing law of torque curve. In the rising stage, the pressure difference on the blade surface continues to increase, which contributes to the abnormal torque increase. In this stage, the flow hits the pressure surface (PS) at a faster speed enlarging the pressure on PS, and the flow separation takes place on the suction surface (SS) weakening the pressure on SS. During the convergence and runaway stage, the pulsation amplitude of torque and axial force under FRC is obviously larger than those under BRC. This is because the rotation frequency of the vortex rope is the same as main pressure fluctuation frequency in impeller under FRC, which enhances the pulsation amplitude. Whereas the vortices are broken due to the inhibitive effect from guide vanes under BRC.
format	article
author	Kan Kan Qingying Zhang Zhe Xu Huixiang Chen Yuan Zheng Daqing Zhou Maxima Binama
author_facet	Kan Kan Qingying Zhang Zhe Xu Huixiang Chen Yuan Zheng Daqing Zhou Maxima Binama
author_sort	Kan Kan
title	Study on a horizontal axial flow pump during runaway process with bidirectional operating conditions
title_short	Study on a horizontal axial flow pump during runaway process with bidirectional operating conditions
title_full	Study on a horizontal axial flow pump during runaway process with bidirectional operating conditions
title_fullStr	Study on a horizontal axial flow pump during runaway process with bidirectional operating conditions
title_full_unstemmed	Study on a horizontal axial flow pump during runaway process with bidirectional operating conditions
title_sort	study on a horizontal axial flow pump during runaway process with bidirectional operating conditions
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/7ab45e30cadf43b192c6c2e29efed217
work_keys_str_mv	AT kankan studyonahorizontalaxialflowpumpduringrunawayprocesswithbidirectionaloperatingconditions AT qingyingzhang studyonahorizontalaxialflowpumpduringrunawayprocesswithbidirectionaloperatingconditions AT zhexu studyonahorizontalaxialflowpumpduringrunawayprocesswithbidirectionaloperatingconditions AT huixiangchen studyonahorizontalaxialflowpumpduringrunawayprocesswithbidirectionaloperatingconditions AT yuanzheng studyonahorizontalaxialflowpumpduringrunawayprocesswithbidirectionaloperatingconditions AT daqingzhou studyonahorizontalaxialflowpumpduringrunawayprocesswithbidirectionaloperatingconditions AT maximabinama studyonahorizontalaxialflowpumpduringrunawayprocesswithbidirectionaloperatingconditions
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Study on a horizontal axial flow pump during runaway process with bidirectional operating conditions

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