Influence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes

The inter-blade passage vortex, the vortex rope of the draft tube, and the vortex in the guide apparatus are the characteristics of flow instability of the Francis turbine, which may lead to fatigue failure in serious cases. In the current study, in order to accurately capture the transient turbulen...

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Autores principales:	Tao Guo, Lihui Xu, Wenquan Wang
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	Francis turbine small guide vane opening large-eddy simulation (LES) Liutex Q criterion vortex identification Technology T
Acceso en línea:	https://doaj.org/article/c68536f834d04e38980780aa89cf14bf
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spelling	oai:doaj.org-article:c68536f834d04e38980780aa89cf14bf2021-11-25T17:27:21ZInfluence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes10.3390/en142276261996-1073https://doaj.org/article/c68536f834d04e38980780aa89cf14bf2021-11-01T00:00:00Zhttps://www.mdpi.com/1996-1073/14/22/7626https://doaj.org/toc/1996-1073The inter-blade passage vortex, the vortex rope of the draft tube, and the vortex in the guide apparatus are the characteristics of flow instability of the Francis turbine, which may lead to fatigue failure in serious cases. In the current study, in order to accurately capture the transient turbulent characteristics of flow under different conditions and fully understand the flow field and vortex structure, we conduct a simulation that adopts sliding grid technology and the large-eddy simulation (LES) method based on the wall-adapting local eddy viscosity (WALE) model. Using the pressure iso-surface method, the Q criterion, and the latest third-generation Liutex vortex identification method, this study analyzes and compares the inter-blade passage vortex, the vortex rope of the draft tube, and the outflow and vortex in the guide apparatus, focusing on the capture ability of flow field information by various vortex identification methods and the unique vortex structure under the condition of a small opening. The results indicate that the dependence of Liutex on the threshold is small, and the scale range of the flow direction vortex captured by Liutex is wider, but the ability of the spanwise vortex is relatively weak. The smaller the opening, the more disorderly the vortexes generated in each component and the more unstable the flow field. In the draft tube, the original shape of the vortex rope is destroyed due to the interaction between vortexes. Under the condition of a small opening, an inter-blade passage vortex is generated, affecting the efficient and stable operation of the turbine.Tao GuoLihui XuWenquan WangMDPI AGarticleFrancis turbinesmall guide vane openinglarge-eddy simulation (LES)LiutexQ criterionvortex identificationTechnologyTENEnergies, Vol 14, Iss 7626, p 7626 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Francis turbine small guide vane opening large-eddy simulation (LES) Liutex Q criterion vortex identification Technology T
spellingShingle	Francis turbine small guide vane opening large-eddy simulation (LES) Liutex Q criterion vortex identification Technology T Tao Guo Lihui Xu Wenquan Wang Influence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes
description	The inter-blade passage vortex, the vortex rope of the draft tube, and the vortex in the guide apparatus are the characteristics of flow instability of the Francis turbine, which may lead to fatigue failure in serious cases. In the current study, in order to accurately capture the transient turbulent characteristics of flow under different conditions and fully understand the flow field and vortex structure, we conduct a simulation that adopts sliding grid technology and the large-eddy simulation (LES) method based on the wall-adapting local eddy viscosity (WALE) model. Using the pressure iso-surface method, the Q criterion, and the latest third-generation Liutex vortex identification method, this study analyzes and compares the inter-blade passage vortex, the vortex rope of the draft tube, and the outflow and vortex in the guide apparatus, focusing on the capture ability of flow field information by various vortex identification methods and the unique vortex structure under the condition of a small opening. The results indicate that the dependence of Liutex on the threshold is small, and the scale range of the flow direction vortex captured by Liutex is wider, but the ability of the spanwise vortex is relatively weak. The smaller the opening, the more disorderly the vortexes generated in each component and the more unstable the flow field. In the draft tube, the original shape of the vortex rope is destroyed due to the interaction between vortexes. Under the condition of a small opening, an inter-blade passage vortex is generated, affecting the efficient and stable operation of the turbine.
format	article
author	Tao Guo Lihui Xu Wenquan Wang
author_facet	Tao Guo Lihui Xu Wenquan Wang
author_sort	Tao Guo
title	Influence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes
title_short	Influence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes
title_full	Influence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes
title_fullStr	Influence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes
title_full_unstemmed	Influence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes
title_sort	influence of upstream disturbances on the vortex structure of francis turbine based on the criteria of identification of various vortexes
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/c68536f834d04e38980780aa89cf14bf
work_keys_str_mv	AT taoguo influenceofupstreamdisturbancesonthevortexstructureoffrancisturbinebasedonthecriteriaofidentificationofvariousvortexes AT lihuixu influenceofupstreamdisturbancesonthevortexstructureoffrancisturbinebasedonthecriteriaofidentificationofvariousvortexes AT wenquanwang influenceofupstreamdisturbancesonthevortexstructureoffrancisturbinebasedonthecriteriaofidentificationofvariousvortexes
_version_	1718412373467856896

Influence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes

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