Next Article in Journal
Identifying Spatially Correlated Patterns between Surface Water and Frost Risk Using EO Data and Geospatial Indices
Previous Article in Journal
Coastal Wetlands: Ecosystems Affected by Urbanization?
Open AccessEditor’s ChoiceArticle

Modeling of the Free-Surface-Pressurized Flow of a Hydropower System with a Flat Ceiling Tail Tunnel

College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210024, Jiangsu, China
*
Author to whom correspondence should be addressed.
Water 2020, 12(3), 699; https://doi.org/10.3390/w12030699
Received: 14 February 2020 / Revised: 29 February 2020 / Accepted: 1 March 2020 / Published: 4 March 2020
(This article belongs to the Section Hydraulics and Hydrodynamics)
For a water diversion hydropower system with a flat ceiling tail tunnel with high elevation, during transient states with relatively low tail water levels, free-surface-pressurized flow inevitably appears and its transient characteristics have obvious effects on the system’s operating stability. Using Newton–Raphson linearization in the characteristic implicit format for modeling of the free-surface-pressurized flow in the tail tunnel, the mathematical models for necessary boundary conditions were derived and linear algebraic equations with a band coefficient matrix were grouped for further transient simulation. Then, a unified mathematical model was established for hydraulic transient analysis of the hydropower system with free-surface-pressurized flow. Combined with experimental research and numerical simulation, the wave speed for the free-surface-pressurized flow was experimentally analyzed for further correctness in the unified model, and by comparative analysis the hydraulic characteristics of the free-surface-pressurized flow in the flat ceiling tail tunnel were investigated. It was found that the derived mathematical model can basically represent water behaviors in the water-surface-pressurized flow, the wave speed for the mixed water-surface-pressurized flow can be set to approximately 50m/s, and with this correctness the numerical results are in good agreement with the experimental results. Therefore, the obtained mathematical model combined with an experimental wave speed or a reference wave speed of 50 m/s for the free-surface-pressurized flow is preferable during the design stage of the hydropower system. View Full-Text
Keywords: free-surface-pressurized flow; characteristic implicit format; hydraulic transient; hydropower system free-surface-pressurized flow; characteristic implicit format; hydraulic transient; hydropower system
Show Figures

Figure 1

MDPI and ACS Style

Zhou, J.; Li, Y. Modeling of the Free-Surface-Pressurized Flow of a Hydropower System with a Flat Ceiling Tail Tunnel. Water 2020, 12, 699.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop