Research on Energy Dissipation in a Discharge Tunnel with a Plug Energy Dissipater

A lot of studies have shown that the hydraulic characteristics of orifice plate are mainly controlled by its contraction ratio, but the thickness of square-edged orifice plate also has many impacts on energy loss characteristics. The primary objective of this study was to investigated the effects of square-edged orifice plate thickness on energy loss characteristics. In this paper, the effects of square-edged orifice plate thickness on energy loss characteristics are investigated by numerical simulation using CFD. Orifice plate discharge tunnel is axial symmetric, two dimensional numerical simulations of orifice plate discharge tunnel flow was used. The equation (9) for calculating energy loss coefficient of square-edged orifice plate energy dissipater considering the influence of thickness is proposed. The results of the present research demonstrate that energy loss coefficient decreases with increase of the orifice plate thickness. The results of model experiment are consistence with the results calculated by using rectified equation in present paper. The CFD simulations and Model experiment for the flow through an orifice plate are carried out. For square-edged orifice plate energy dissipater, the relative orifice plate thickness T/D has remarkable impacts on its energy loss coefficient ξ. The Traditional equation (8) is corrected by numerical results. The equation (9) for calculating energy loss coefficient of square-edged orifice plate energy dissipater considering the influence of thickness is proposed and this equation is available in the condition of d/D = 0.4–0.8, T/D = 0.05–0.25, and Re > 105(Re is Reynolds number). Comparing with the physical model experimental data, the relative errors of equation (9) is smaller than 15%.

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Hydraulic Model Investigation on Stepped Spillway's Plain and Slotted Roller Bucket

Engineering, Technology & Applied Science Research ◽

10.48084/etasr.2837 ◽

2019 ◽

Vol 9 (4) ◽

pp. 4419-4422

Author(s):

A. S. Kote ◽

P. B. Nangare

Keyword(s):

Energy Dissipation ◽

Kinetic Energy ◽

Hydraulic Model ◽

Physical Models ◽

Stepped Spillway ◽

Stilling Basin ◽

Discharge Water ◽

Energy Dissipater ◽

Low Head ◽

High Head

In ogee spillway, the released flood water from crest to toe possesses a high amount of kinetic energy causing scour and erosion on the spillway structure. The dam projects normally have a stilling basin as an energy dissipater which has specific energy dissipation limitations. The stepped spillway is a better option to minimize kinetic energy along the chute and safely discharge water in the river domain. The Khadakwasla dam is situated in Pune, Maharashtra (India), and has scouring and erosion issues on the chute of ogee spillway and on the stilling basin. The present study develops a physical hydraulic model for the dam spillway with steps, plain and slotted roller bucket as per IS Code 6934 (1998) and IS Code 7365 (2010). Experiments were performed at heads of 4m (low head) and 6m (high head) on the developed physical models, namely on the plain and slotted roller bucket model for the ogee spillway and the plain and slotted roller bucket model for the stepped spillway. It was found that the plain roller bucket of ogee spillway dissipates 81.26% of energy at the low head, whereas the stepped spillway with slotted roller bucket dissipates the 83.86% of the energy at the high head.

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Velocity and pressure distributions in discharge tunnel of rotary-obstruction composite inner energy dissipation

Science China Technological Sciences ◽

10.1007/s11431-011-4633-4 ◽

2011 ◽

Vol 54 (S1) ◽

pp. 111-117 ◽

Cited By ~ 2

Author(s):

ShuangLi Cao ◽

ZhengMing Niu ◽

Jian Yang ◽

HongBo Lu

Keyword(s):

Energy Dissipation ◽

Discharge Tunnel ◽

Pressure Distributions

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EXPERIMENTAL STUDY ON THE SIDE CHANNEL SPILLWAY AND ITS IMPACT ON THE JUMP, CROSS FLOW AND ENERGY DISSIPATION

Jurnal Teknologi ◽

10.11113/jt.v81.13811 ◽

2019 ◽

Vol 81 (6) ◽

Author(s):

Djoko Legono ◽

Roby Hambali ◽

Denik Sri Krisnayanti

Keyword(s):

Experimental Study ◽

Energy Dissipation ◽

Water Surface ◽

Cross Flow ◽

Side Channel ◽

Hydraulic Jumps ◽

Stilling Basin ◽

Energy Dissipater ◽

Design Discharge ◽

The Cross

The utilization of the side channel spillway as the primary component of dam is generally due to the limitation of the available space to construct conventional spillway with design discharge capacity. Some impacts may only be identified through the hydraulic physical model study; these include the presence of the chaotic jumps at the downstream of the spillway crest, the cross flow on the steep channel, as well as the performance of the energy dissipation in the stilling basin. This paper presents the result of the experimental study of three-dimensional behaviour of flow over the entire components of the side channel spillway of Bener Dam, Indonesia. The main dam and its appurtenant components, i.e., the reservoir, the spillway crest, the spillway channel, and the energy dissipaters were built, and various discharges were introduced to study the hydraulic performance of the spillway crest, the stilling basin, the chute, and the energy dissipater. The observed data were collected and then analysed. The results show that firstly, some chaotic hydraulic jumps were found at the stilling basin at downstream spillway crest. These chaotic hydraulic jumps would produce significant vibration that may endanger the nearby structures. Secondly, the presence of the cross flow along the steep channel downstream of the stilling basin may also need to be eliminated in such that its impact on the rise of water surface level does not create any objection. This may be carried out through the installation of baffles along the spillway channel bed. Thirdly, the presence of the hydraulic jumps at the energy dissipater basin under the design discharge has proven that the energy dissipater has performed well where local scour around the downstream structure was found to be not significant. However, to anticipate the raising of the water surface elevation at the energy dissipater basin, increasing the elevation of energy dissipater wall from +212.50 m to +215.00 m is highly recommended.

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