Abstract
Toothed internal energy dissipaters (TIED) are a new type of internal energy dissipaters, which combines the internal energy dissipaters of sudden reduction and sudden enlargement forms with the open-flow energy dissipation together. In order to provide a design basis for an optimized body type of the TIED, the effect of the area contraction ratio (ε) on the hydraulic characteristics, including over-current capability, energy dissipation rate, time-averaged pressure, pulsating pressure, time-averaged velocity, and pulsating velocity, were studied using the methods of a physical model test and theoretical analysis. The main results are as follows. The over-current capability mainly depends on ε, and the larger ε is, the larger the flow coefficient is. The energy dissipation rate is proportional to the quadratic of Re and inversely proportional to ε. The changes of the time-averaged pressure coefficients under each flow are similar along the test pipe, and the differences of the time-averaged pressure coefficient between the inlet of the TIED and the outlet of the TIED decrease with the increase of ε. The peaks of the pulsating pressure coefficient appear at 1.3 D after the TIED and are inversely proportional to ε. When the flow is 18 l/s and ε increases from 0.375 to 0.625, the maximum of time-averaged velocity coefficient on the line of Z/D = 0.42 reduces from 2.53 to 1.17, and that on the line of Z/D = 0 decreases from 2.99 to 1.74. The maximum values of pulsating velocity on the line of Z/D = 0.42 appear at 1.57D and those of Z/D = 0 appear at 2.72D, when the flow is 18 l/s. The maximum values of pulsating velocity decrease with the increase of ε. Finally, two empirical expressions, related to the flow coefficient and energy loss coefficient, are separately presented.
Highlights
The internal energy dissipater effectively reduces the downstream flow speed, smoothly connects the downstream flow, and avoids the erosion of the river channel by a traditional energy dissipater in a water conservancy project with high water head and high flow
Some researchers mainly focused on the energy dissipation rate and over-current capability of internal energy dissipaters with different body types and area contraction ratios
The body shape of internal energy dissipater was the key to analyze the variation of the hydraulic characteristics, and the area contraction ratio was the most critical body geometry parameter influencing the hydraulic characteristic of the toothed internal energy dissipaters (TIED)
Summary
The internal energy dissipater effectively reduces the downstream flow speed, smoothly connects the downstream flow, and avoids the erosion of the river channel by a traditional energy dissipater in a water conservancy project with high water head and high flow. The area contraction ratio (ε) of internal energy dissipation with sudden enlargement and reduction was an important geometric factor to decide its hydraulic characteristics. The body shape of internal energy dissipater was the key to analyze the variation of the hydraulic characteristics, and the area contraction ratio was the most critical body geometry parameter influencing the hydraulic characteristic of the TIED. In order to study the effect of the area contraction ratio (ε) on the hydraulic characteristics of TIED, it is necessary to confirm the length, height, and angle of piers. The effect of the pier’s height on the hydraulic characteristics of the toothed internal energy dissipate (TIED) was studied via a physical model test [22]. Five different types of the TIED with four toothed piers (the length of each toothed piers is 0.9D), which have different area contraction ratios (ε), were designed and used to experimentally study the effect of the area contraction ratio (ε) on hydraulic characteristics
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
