scholarly journals Numerical Investigation of Erosion Wear Characteristics of Hydraulic Spillway

2021 ◽  
Vol 11 (17) ◽  
pp. 8118
Author(s):  
Cong Zhang ◽  
Yuqi Zhang ◽  
Huadong Zhao ◽  
Mao Wang ◽  
Tongtong Wang
Keyword(s):  
Flow Velocity ◽  
Simulation Analysis ◽  
Sediment Concentration ◽  
Work Conditions ◽  
Water Diversion ◽  
Erosion Wear ◽  
Discrete Phase Model ◽  
Distribution Law ◽  
Obvious Effect ◽  
Gate Opening

There are many sand-laden waters in China, and the wear of hydraulic structures caused by sand-laden water diversion has been paid more and more attention. Taking the spillway of a reservoir as the research object, the numerical model of erosion wear caused by sediment-laden particle flows on the spillway was established by using the computational fluid dynamics (CFD) method, VOF (Volume of Fluid) multiphase flow model and DPM (Discrete Phase Model). Through the simulation analysis of the spillway’s overall erosion, the distribution of the spillway erosion wear was obtained. Then, according to the main wear parts, the single variable, such as sediment diameter, sediment concentration, flow velocity and gate opening degree, was changed to study the erosion amount of the spillway and the distribution law of the spillway erosion parts. The results show that the main erosion sites of the spillway are at the bottom of the gate chamber and the middle section of the spillway. The maximum erosion increases linearly with the increase in sediment concentration. With the increase in sediment concentration, the sediment concentration changed from 1 kg/m3 to 6 kg/m3, and the maximum erosion of the spillway increased from 2.58 × 10−7 kg/m2 to 1.53 × 10−6 kg/m2. The erosion at the bottom of the spillway and gate leaf increases first and then decreases with the increase in sediment diameter and reaches the maximum value when the particle size is 0.002 mm. The erosion at the bottom of the spillway and the gate leaf increases with different growth trends as the flow velocity increases, when the flow velocity increases from 2 m/s to 9 m/s and the maximum erosion amount at the bottom of the spillway increases from 3.66 × 10−7 kg/m2 to 1.14 × 10−6 kg/m2, and the maximum erosion of the gate leaf increased from 1.66 × 10−8 kg/m2 to 8.98 × 10−6 kg/m2. The erosion amount at the bottom of the spillway increases with the increase in the gate opening between 0 and 3 m and tends to be stable when the gate opening is greater than 3 m. The maximum erosion position moves to the rear part of the spillway with the change in the gate opening. The change in the gate opening has no obvious effect on the erosion amount of the gate leaf but only changes the area of the gate erosion part. Thus, the erosion wear distribution of spillway under different work conditions is summarized, and the qualitative study between the erosion wear and the distribution of sediment diameter, sediment concentration, flow velocity and gate opening degree is made.

Simulation Analysis for Reinforced Concrete Aqueduct of Lijia Pumping Station

2014 ◽  
Vol 488-489 ◽  
pp. 605-608
Author(s):  
Xiang Zan Xie
Keyword(s):  
Reinforced Concrete ◽  
Simulation Analysis ◽  
Water Pressure ◽  
Water Diversion ◽  
Distribution Law ◽  
Masonry Arch ◽  
Pumping Station ◽  
Earthquake Effect ◽  
Concrete Masonry ◽  
Cushion Layer

Reinforced concrete masonry arch aqueduct is a common water diversion engineering structure. Aqueduct is decorated on the concrete cushion layer, cushion layer effects on masonry arch, the structures stress is uniform, carrying capacity is strong. This paper adopts finite element method to carry out force analysis for reinforced concrete masonry arch aqueduct of Lijia pumping station, considering aqueduct weight, water pressure and earthquake effect, etc. Researching stress and deformation distribution law of reinforced concrete masonry arch aqueduct.

Experimental and Numerical Investigation on the Erosion Wear of an Impact Sprinkler

2014 ◽  
Author(s):  
Yuncheng Xu ◽  
Guan Lin ◽  
Haijun Yan
Keyword(s):  
Internal Flow ◽  
Internal Surface ◽  
Sprinkler Irrigation ◽  
Sediment Concentration ◽  
Western China ◽  
Erosion Wear ◽  
Discrete Phase Model ◽  
Discrete Phase ◽  
The Cost ◽  
The Impact

In the middle and western China, agricultural irrigation water often contains a high sediment concentration. In order to save the cost, no filtration devices are required for sprinkler irrigation, which results in the wear of sprinkling irrigation equipment, especially on the nozzle. In this study, experiments on the erosion wear of an impact sprinkler (PY1-20sh with aluminum alloy nozzles) were conducted under different conditions of sediment concentration and erosion time. Using the experimental data as boundary conditions, numerical simulations based on the discrete phase model (DPM) were conducted to analyze the wear of the internal surface of the sprinkler’s full flow passage. Based on both experimental and numerical results, the erosion wear mechanism of the internal flow surface was revealed, and prediction model of the nozzle’s wear rate was established, providing the technical guidance for design and operation of the impact sprinkler.

Experimental Study on Hydraulic Roughness of Submerged Grass in Ecological Riverbank

2013 ◽  
Vol 838-841 ◽  
pp. 1743-1748
Author(s):  
Dian Guang Ma ◽  
Chun Xin Zhong ◽  
Wu Ning ◽  
Qing Ye ◽  
Sheng Zhu
Keyword(s):  
Flow Velocity ◽  
Roughness Coefficient ◽  
Theoretic Analysis ◽  
Mean Flow ◽  
Normal Range ◽  
Obvious Effect ◽  
Hydraulic Roughness ◽  
Natural Turf ◽  
Scouring Process ◽  
The Mean

A model experiment about the hydraulic roughness of natural turf used in riverbank was carried out in flume. To examine the rationality of experimental design, the hydraulic roughness coefficient of plexiglass-flume was tested firstly. The result was 0.0085, which is quite normal. Then the tested hydraulic roughness caused by vegetation ranges from 0.020 to 0.090 for the chosen plants, which is also acceptable. Furthermore, the tested incipient velocities of krasnozem, and paddysoil had the range of 0.55~0.65m·s-1 and 1.0~1.1m·s-1, respectively. All these experimental results are in normal range, which means that the design of this experimental is rational. Experimental research illustrate that, the roughness coefficient of plant reduces with the increasing of flow velocity. When the mean flow velocity is over 3m·s-1, Mannings n values vary between 0.025 and 0.035. This phenomenon is accord with the theoretic analysis. During the scouring process, not only the flow velocity, but also the flow duration has an obvious effect on the coarseness of vegetative bed.

scholarly journals Numerical Simulation Analysis of Combined Seismic Response for Rock-Lining-Water in Hydraulic Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Guoqing Liu ◽  
Yanhong Zhang ◽  
Ming Xiao
Keyword(s):  
Numerical Simulation ◽  
Seismic Response ◽  
Simulation Analysis ◽  
Large Diameter ◽  
Water Diversion ◽  
Seismic Stability ◽  
Central Difference ◽  
Element Analysis ◽  
Internal Water ◽  
Lining Structure

In order to explore the influence of internal water on the seismic response of hydraulic tunnel, the combined mechanical analysis models of multimaterial including surrounding rock, lining structure, and internal water are built. Based on the explicit central difference method, the dynamic finite element analysis methods for rock, lining, and water are discussed, respectively. The dynamic contact force method is used to simulate the rock-lining contact interaction, and the arbitrary Lagrange-Euler (ALE) method is used to simulate the lining-water coupling interaction. Then a numerical simulation analysis method for combined seismic response of rock-lining-water system in hydraulic tunnel is proposed, and the detailed solving steps are given. This method is used to study the seismic stability characteristics of the water diversion tunnel in a hydropower station, and the displacement, stress, and damage failure characteristics of the lining structure under the conditions of no water, static water, and dynamic water are comparatively analyzed. The results show that the hydrostatic pressure restricts the seismic response of the lining, while the hydrodynamic pressure exacerbates its seismic response and leads to damage, separation, and slip failure appearing on the haunch, which can provide a scientific reference for the seismic design of hydraulic tunnel with high water head and large diameter.

Calculation and Analysis of Reinforced Concrete Continuous Box-Girder Overpass

2011 ◽  
Vol 101-102 ◽  
pp. 463-466
Author(s):  
Dong Yu Ji
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Simulation Analysis ◽  
Great Influence ◽  
Distribution Law ◽  
Box Girder ◽  
Common Structure ◽  
Element Simulation ◽  
Stress And Deformation ◽  
Calculation Software

Reinforced concrete continuous box-girder overpass is a common structure form, Wangzhuang overpass is example, this paper adopts universal finite element calculation software to carry out finite element simulation analysis for reinforced concrete continuous box-girder overpass. Considering the influence of overpass structure weight and driveway load, the distribution law of overpass stress and displacement were researched. Analysis results show that, load’s short-term effect combination has great influence on overpass structure, driveway slanting load’s influence on overpass structure’s stress and deformation can not be ignored.

Temperature Influence on Absorption and Stripping Processes

1987 ◽  
Vol 19 (5-6) ◽  
pp. 877-888
Author(s):  
Boris M. Khudenko ◽  
Alberto Garcia-Pastrana
Keyword(s):  
Simulation Analysis ◽  
Critical Energy ◽  
Temperature Correction ◽  
Gas Absorption ◽  
Gas Transfer ◽  
Distribution Law ◽  
Transfer Energy ◽  
Transfer Rates ◽  
Influence Of Temperature On ◽  
Transfer Apparatus

The influence of temperature on mass transfer rates in gas absorption and stripping processes has been evaluated. A computer simulation analysis has been used to identify fundamental reasons for variations among temperature correction factors published in the literature. A critical molecular transfer energy was postulated and the temperature correction factor was developed based on the Maxwell distribution law. The critical energy hypothesis was experimentally validated and the critical energy of molecules crossing the gas-liquid interface of 2.6.10−13 erg was determined for both methane and oxygen in the temperature range from 5° to 75°C. The critical energy was found to be a constant value for various hydrodynamic conditions and also for water with and without surfactants. The temperature correction expression derived based on the critical energy hypothesis was compared with several published relationships. The comparison has corroborated that the developed temperature correction relationship is applicable to various gas transfer apparatus and hydrodynamic regimes.

scholarly journals Vertical Distribution of Suspended Sediments above Dense Plants in Water Flow

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 12 ◽  
Author(s):  
Yanhong Li ◽  
Liquan Xie ◽  
Tsung-chow Su
Keyword(s):  
Vertical Distribution ◽  
Flow Velocity ◽  
Suspended Sediment ◽  
Plant Height ◽  
Water Flow ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Turbulent Momentum ◽  
Different Diameters ◽  
Plane Displacement

Plants in natural water flow can improve water quality by adhering and absorbing the fine suspended sediments. Dense plants usually form an additional permeable bottom boundary for the water flow over it. In the flow layer above dense plants, the flow velocity generally presents a zero-plane-displacement and roughness-height double modified semi-logarithmic profile. In addition, the second order shear turbulent moment (or the Reynolds stress) are different from that found in non-vegetated flow. As a result, the turbulent momentum diffusivity of flow and thus the diffusivity of sediment will shift, which will cause the vertical profile of suspended sediment and the corresponding Rouse formula deform. A set of physical experiments with three different diameters of fine suspended sediments was conducted in an indoor water flume. These experiments investigated a new distribution pattern of suspended sediment and the correspondingly deformed Rouse formula in the flow layer over the dense plants. Experimental results showed that above the dense plants, the shear turbulent momentum of flow presented a plant-height modified negative linear profile, which has been proposed by a previous study, and the vertical distribution of fine suspended sediments presented an equilibrium pattern. Based on the plant-modified profiles of flow velocity and the shear turbulent momentum a new zero-plane and plant-height double modified Rouse formula were analytically derived. This double-parameter modified Rouse formula agrees well with the measured profile of suspended sediment concentration experimentally observed in the present study. By adjusting the Prandtl–Schmidt number, i.e., the ratio of sediment diffusivity to flow diffusivity, the double-parameter modified Rouse formula can be applied to submerged dense plant occupied flow.

Dynamics of Suspended Sediments Related to Fine Particles in Lower Mekong River

2013 ◽  
Vol 446-447 ◽  
pp. 1528-1533
Author(s):  
Sarunya Promkotra
Keyword(s):  
Shear Stress ◽  
Flow Velocity ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Fine Particles ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Mekong River ◽  
Fall Velocity ◽  
Stream Discharge

Analytical results are considered the factors of suspended sediment concentration, fall velocity, dimensionless shear stress, transportation rate and stream discharge. As a result of suspended sediments of Loei, Huang and Mekong River, fine particles account for the applicability in sediment deposits. Floating suspended sediments explicit more clay minerals than suspended sediments. Suspended sediment concentration (SSC) in the estuarine of Loei River and Huang River are moderately less than Mekong River. Flow directions of the interconnected rivers to the mainstream-Mekong River lead to the quantity of SSC. Sediment concentrations attain to the dynamic response. Dimensionless shear stress relates to shear velocity, geometry and grain size of particles, and difference of flow velocity. This shear stress is directly comparative to flow velocity and clay mineral concentrations. The transport rate involves in the flow velocity, SSC and depth of the river. Moreover, stream discharge can be presumed by the geometry of the river and topography of sampling locations.

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