Hydraulic Characteristics of Multistage Orifice Tunnels

Zhang, Q. Y.; Chai, Bei-Bei

doi:10.1061/(asce)0733-9429(2001)127:8(663)

Cited by 9 publications

(5 citation statements)

References 3 publications

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“…Wang et al [23] conducted compressibility tests to examine the mechanical properties of asphalt concrete under low-temperature conditions and underscored the importance of acknowledging and managing temperature effects to ensure the durability and quality of asphalt concrete. By subjecting it to varying temperatures, Zhang et al [24] observed that temperature indeed influences the mechanical properties of asphalt concrete. Chen et al [25] scrutinized asphalt with different oil/stone ratios at varying temperatures and concluded that temperature affects the stress and strain of asphalt concrete specimens.…”

Section: Introductionmentioning

confidence: 99%

Study on the Effect of Asphalt Static Conditions on the Tensile Properties of Acidic Aggregate Hydraulic Asphalt Concrete

Bao,

He,

Wang

et al. 2024

Materials

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Hydraulic asphalt concrete is known for its excellent seepage control performance and strong deformation resistance. This engineering material has widespread applications in the seepage control structures of hydraulic buildings. Recent projects have investigated the use of acidic aggregates to improve economic efficiency. However, they have also highlighted the weaker adhesion between acidic aggregates and asphalt, which necessitates stringent construction process control. This study investigates the impact of resting conditions on the tensile properties of acidic aggregate hydraulic asphalt concrete. The results of the tensile testing indicate that the storage time significantly affects the performance of asphalt concrete. The tensile strength of the specimens without anti-stripping agents decreased from 1.711 MPa to 0.914 MPa after resting periods of 0, 10, 20, and 30 days. The specimens treated with anti-stripping agents also showed a decrease in tensile strength over time, similar to the trend observed in the previous specimens. Digital specimen simulations indicated a decrease in cohesion between the asphalt and the aggregate from 5.375 MPa to 2.664 MPa after 30 days, representing a reduction of 50.44%. To counteract the effect of the storage time on the bonding between acidic aggregates and asphalt, this study recommends reducing the grading index and maximum size of aggregates, decreasing the coarse aggregate content, and selecting smooth aggregate shapes.

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Section: Introductionmentioning

confidence: 99%

Study on the Effect of Asphalt Static Conditions on the Tensile Properties of Acidic Aggregate Hydraulic Asphalt Concrete

Bao,

He,

Wang

et al. 2024

Materials

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“…It is well understood that three-dimensional (3D) wall jets are typically characterized by the interaction between a turbulent boundary layer and a free jet. Because of their diverse practical engineering applications (e.g., film cooling [1], heat transfer [2], and energy dissipation in hydraulic structure [3][4][5][6][7][8]), a number of experimental studies on the mean flow development in the jet have been conducted in the past few decades. The experiments of 3D wall jet issuing from rectangular orifices have been firstly performed by Sforza and Herbst [9].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Mean Flow Development of a Three-Dimensional Wall Jet Confined by a Vertical Baffle

Chen

Huang

Zhang

et al. 2019

Water

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Three-dimensional (3D) confined wall jets have various engineering applications related to efficient energy dissipation. This paper presents experimental measurements of mean flow development for a 3D rectangular wall jet confined by a vertical baffle with a fixed distance (400 mm) from its surface to the nozzle. Experiments were performed at three different Reynolds numbers of 8333, 10,000 and 11,666 based on jet exit velocity and square root of jet exit area (named as B), with water depth of 100 mm. Detailed measurements of current jet were taken using a particle image velocimetry technique. The results indicate that the confined jet seems to behave like an undisturbed jet until 16B downstream. Beyond this position, however, the mean flow development starts to be gradually affected by the baffle confinement. The baffle increases the decay and spreading of the mean flow from 16B to 23B. The decay rate of 1.11 as well as vertical and lateral growth rates of 0.04 and 0.19, respectively, were obtained for the present study, and also fell well within the range of values which correspond to the results in the radial decay region for the unconfined case. In addition, the measurements of the velocity profiles, spreading rates and velocity decay were also found to be independent of Reynolds number. Therefore, the flow field in this region appears to have fully developed at least 4B earlier than the unconfined case. Further downstream (after 23B), the confinement becomes more pronounced. The vertical spreading of current jet shows a distinct increase, while the lateral growth was found to be decreased significantly. It can be also observed that the maximum mean velocity decreases sharply close to the baffle.

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“…For example, standardized shapes allow the measurement of the discharge Q through a pipe while monitoring the pressure differences on both sides of the device (ASME, 2004;EN ISO, 2003). In connection with a spillway, such a structure can be added to dissipate a large amount of energy (Jianhua et al, 2010;Zhang & Chai, 2001). This paper focuses on applications that work as a throttle in a surge tank of a hydro power plant (HPP).…”

Section: Introductionmentioning

confidence: 99%

Design criteria for a type of asymmetric orifice in a surge tank using CFD

Gabl

Righetti

2018

Engineering Applications of Computational Fluid Mechanics

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An asymmetric orifice can be added to a surge tank of a hydro power plant to dampen the mass oscillation. This allows a reduction of the required volume and a more stable behavior of the overall hydraulic system. In this paper, the advantage of a typical asymmetric orifice is shown in comparison with a sharp-edged geometry with two different pipe diameters. The software ANSYS-CFX is used to investigate the influence of the individual geometry parameters (radius, length, angle at the forefront) on the local head loss coefficients and the ratio of the two flow directions. Furthermore, a coefficient is analyzed based on an equation from the literature for the sharp-edged structure, which can be used comparably for the asymmetric orifice. This allows us to reach preliminary assumptions of the losses at an early state of the design process. The following adaptation can be supported by the presented guidance for the optimization process, so that a suitable geometry for the specific boundary conditions can be found. ARTICLE HISTORY KEYWORDSControl structures; flows in pipes and nozzles; hydraulics of renewable energy systems; hydraulic structure design and management; RANS model

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Hydraulic Characteristics of Multistage Orifice Tunnels

Cited by 9 publications

References 3 publications

Study on the Effect of Asphalt Static Conditions on the Tensile Properties of Acidic Aggregate Hydraulic Asphalt Concrete

Study on the Effect of Asphalt Static Conditions on the Tensile Properties of Acidic Aggregate Hydraulic Asphalt Concrete

Experimental Investigation on Mean Flow Development of a Three-Dimensional Wall Jet Confined by a Vertical Baffle

Design criteria for a type of asymmetric orifice in a surge tank using CFD

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