Hydraulic performance of helical-step dropshaft

Aiming to achieve energy dissipation and prevention of cavitation erosion, a kind of dropshaft in urban drainage systems called the helical-step dropshaft is introduced in this paper. It dissipates flow energy by means of step geometry and prevents cavitation erosion through air entrainment. To veri...

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Autores principales:	Weichen Ren, Jianhua Wu, Fei Ma, Shangtuo Qian
Formato:	article
Lenguaje:	EN
Publicado:	IWA Publishing 2021
Materias:	air entrainment drop structure energy dissipation helical-step dropshaft urban drainage system Environmental technology. Sanitary engineering TD1-1066
Acceso en línea:	https://doaj.org/article/74877a38b5394214aae5df7669c16709
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id	oai:doaj.org-article:74877a38b5394214aae5df7669c16709
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spelling	oai:doaj.org-article:74877a38b5394214aae5df7669c167092021-11-06T11:18:27ZHydraulic performance of helical-step dropshaft0273-12231996-973210.2166/wst.2021.295https://doaj.org/article/74877a38b5394214aae5df7669c167092021-08-01T00:00:00Zhttp://wst.iwaponline.com/content/84/4/954https://doaj.org/toc/0273-1223https://doaj.org/toc/1996-9732Aiming to achieve energy dissipation and prevention of cavitation erosion, a kind of dropshaft in urban drainage systems called the helical-step dropshaft is introduced in this paper. It dissipates flow energy by means of step geometry and prevents cavitation erosion through air entrainment. To verify its availability, the hydraulic characteristics of the helical-step dropshaft were experimentally investigated, including the flow regimes, the efficiency of energy dissipation, characteristics of air entrainment and pressure distribution. The results demonstrate that, even for a large discharge, flow can be discharged smoothly and steadily, and a high energy-dissipation rate of over 87% is achieved. There are three distinct flow regimes observed in the dropshaft, namely nappe flow, mixed flow and skimming flow. Moreover, there is no less than 1.6% air concentration and a reasonable pressure distribution on the step surface. This study provides an attractive alternative for the design of drop structures. HIGHLIGHTS A novel helical-step dropshaft prototype was modelled and verified by experimentally studying its hydraulic characteristics.; Flow regimes in the dropshaft were specially observed and a novel mixed flow regime for the helical stepped chute was defined and described.; Air concentration near the step surface was measured to help understand the cavitation prevention in the helical-step dropshaft for the first time.;Weichen RenJianhua WuFei MaShangtuo QianIWA Publishingarticleair entrainmentdrop structureenergy dissipationhelical-step dropshafturban drainage systemEnvironmental technology. Sanitary engineeringTD1-1066ENWater Science and Technology, Vol 84, Iss 4, Pp 954-965 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	air entrainment drop structure energy dissipation helical-step dropshaft urban drainage system Environmental technology. Sanitary engineering TD1-1066
spellingShingle	air entrainment drop structure energy dissipation helical-step dropshaft urban drainage system Environmental technology. Sanitary engineering TD1-1066 Weichen Ren Jianhua Wu Fei Ma Shangtuo Qian Hydraulic performance of helical-step dropshaft
description	Aiming to achieve energy dissipation and prevention of cavitation erosion, a kind of dropshaft in urban drainage systems called the helical-step dropshaft is introduced in this paper. It dissipates flow energy by means of step geometry and prevents cavitation erosion through air entrainment. To verify its availability, the hydraulic characteristics of the helical-step dropshaft were experimentally investigated, including the flow regimes, the efficiency of energy dissipation, characteristics of air entrainment and pressure distribution. The results demonstrate that, even for a large discharge, flow can be discharged smoothly and steadily, and a high energy-dissipation rate of over 87% is achieved. There are three distinct flow regimes observed in the dropshaft, namely nappe flow, mixed flow and skimming flow. Moreover, there is no less than 1.6% air concentration and a reasonable pressure distribution on the step surface. This study provides an attractive alternative for the design of drop structures. HIGHLIGHTS A novel helical-step dropshaft prototype was modelled and verified by experimentally studying its hydraulic characteristics.; Flow regimes in the dropshaft were specially observed and a novel mixed flow regime for the helical stepped chute was defined and described.; Air concentration near the step surface was measured to help understand the cavitation prevention in the helical-step dropshaft for the first time.;
format	article
author	Weichen Ren Jianhua Wu Fei Ma Shangtuo Qian
author_facet	Weichen Ren Jianhua Wu Fei Ma Shangtuo Qian
author_sort	Weichen Ren
title	Hydraulic performance of helical-step dropshaft
title_short	Hydraulic performance of helical-step dropshaft
title_full	Hydraulic performance of helical-step dropshaft
title_fullStr	Hydraulic performance of helical-step dropshaft
title_full_unstemmed	Hydraulic performance of helical-step dropshaft
title_sort	hydraulic performance of helical-step dropshaft
publisher	IWA Publishing
publishDate	2021
url	https://doaj.org/article/74877a38b5394214aae5df7669c16709
work_keys_str_mv	AT weichenren hydraulicperformanceofhelicalstepdropshaft AT jianhuawu hydraulicperformanceofhelicalstepdropshaft AT feima hydraulicperformanceofhelicalstepdropshaft AT shangtuoqian hydraulicperformanceofhelicalstepdropshaft
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Hydraulic performance of helical-step dropshaft

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