Fluid Dynamics Analysis of Flow Characteristics in the Clearance of Hydraulic Turbine Seal Rings

Leilei Chen, Wenhao Wu, Jian Deng, Bing Xue, Liuming Xu, Baosheng Xie and Yuchuan Wang ()
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Leilei Chen: Hubei Technology Innovation Center for Smart Hydropower, Wuhan 430000, China
Wenhao Wu: College of Water Conservancy and Construction Engineering, Northwest A&F University, Yangling 712100, China
Jian Deng: Hubei Technology Innovation Center for Smart Hydropower, Wuhan 430000, China
Bing Xue: Hubei Technology Innovation Center for Smart Hydropower, Wuhan 430000, China
Liuming Xu: Hubei Technology Innovation Center for Smart Hydropower, Wuhan 430000, China
Baosheng Xie: College of Water Conservancy and Construction Engineering, Northwest A&F University, Yangling 712100, China
Yuchuan Wang: College of Water Conservancy and Construction Engineering, Northwest A&F University, Yangling 712100, China

Energies, 2025, vol. 18, issue 14, 1-19

Abstract: The hydraulic turbine serves as the cornerstone of hydropower generation systems, with the sealing system’s performance critically influencing energy conversion efficiency and operational cost-effectiveness. The sealing ring is a pivotal component, which mitigates leakage and energy loss by regulating flow within the narrow gap between itself and the frame. This study investigates the intricate flow dynamics within the gap between the sealing ring and the upper frame of a super-large-scale Francis turbine, with a specific focus on the rotating wall’s impact on the flow field. Employing theoretical modeling and three-dimensional transient computational fluid dynamics (CFD) simulations grounded in real turbine design parameters, the research reveals that the rotating wall significantly alters shear flow and vortex formation within the gap. Tangential velocity exhibits a nonlinear profile, accompanied by heightened turbulence intensity near the wall. The short flow channel height markedly shapes flow evolution, driving the axial velocity profile away from a conventional parabolic pattern. Further analysis of rotation-induced vortices and flow instabilities, supported by turbulence kinetic energy monitoring and spectral analysis, reveals the periodic nature of vortex shedding and pressure fluctuations. These findings elucidate the internal flow mechanisms of the sealing ring, offering a theoretical framework for analyzing flow in microscale gaps. Moreover, the resulting flow field data establishes a robust foundation for future studies on upper crown gap flow stability and sealing ring dynamics.

Keywords: turbine; seal ring; shear flow; flow analysis; micro-gap flow; CFD simulation (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2025
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