scholarly journals Study on the Rectification of Forebay in Pumping Station

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Weiwei Song ◽  
Yong Pang ◽  
Xiaohuan Shi ◽  
Qing Xu
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Three Dimensional ◽  
Bottom Layer ◽  
Control Measures ◽  
Three Dimensional Model ◽  
Inlet Channel ◽  
Pumping Station ◽  
Pump Station ◽  
Comparison Of The Results

The forebay of pumping stations is an important hydraulic structure that connects the channel with the inlet channel. Actual test observations and theoretical studies have shown that poor precursors produce backflow, vortex, and water flow disturbances in the forebay water. In this paper, taking a lateral inlet pump station as an example, we study the nonmeasures and five rectification measures—“Y” type diversion pier, “T” shaped diversion pier, narrow bottom hole, high and wide bottom, and diversion wall—through adopting the method of numerical simulation and model test. For the numerical simulation, the corresponding three-dimensional model is established by UG solid modeling software, and then the computational fluid is simulated numerically with CFX. Based on the analysis and comparison of the results during the test of numerical simulation and model test, the stability of the rectification measures is considered after taking into consideration the results of the uniformity test of the velocity distribution of the surface layer, the bottom layer, and the front section of each scheme. The proposed scheme 3 (“T” diversion pier) is regarded as the pumping station flow control measures.

scholarly journals Analysis of the Flow Pattern and Flow Rectification Measures of the Side-Intake Forebay in a Multi-Unit Pumping Station

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2025
Author(s):  
Ahmed Nasr ◽  
Fan Yang ◽  
Yiqi Zhang ◽  
Tieli Wang ◽  
Mahmoud Hassan
Keyword(s):  
Numerical Simulation ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Flow Pattern ◽  
Three Dimensional ◽  
Operating Efficiency ◽  
Water Tank ◽  
Three Dimensional Model ◽  
Pumping Station ◽  
Area Reduction

To improve the problem of turbulence in the forebay of the lateral inlet pumping station, a typical lateral inlet pumping station project in Xuzhou, Jiangsu Province, China was taken as the research object. The forebay of the pumping station is a building connecting the river channel and the pumping station into the water tank. Based on the Reynolds-averaged Navier-Stokes (RANS) law and the turbulence model, the computational fluid dynamics method (CFD) technology compares and analyzes the numerical simulation with or without rectification measures for the forebay of the lateral intake pumping station when multiple units are operating. The three-dimensional model was created by SolidWorks modeling software and the numerical simulation simulated by CFX-ANSYS. To alter the flow pattern in the forebay of the pumping station, various rectification measures were chosen. Internal rectification flow patterns in the forebay under multiple plans, uniformity of flow velocity distribution in the measuring section, and vortex area reduction rates are investigated and compared. Based on the analysis and comparison of numerical simulation results, when the parabolic wall and some rectification piers are set significantly it improves the flow pattern of the forebay of the lateral inlet pumping station. It also makes the flow pattern of the inlet pool better and increases the uniformity of the flow velocity distribution by 8%. Further, it reduced the vortex area by 70%, effectively improving the operating efficiency of the pump. The research results of this paper provide a technical reference for the improvement of the flow pattern in the forebay of the lateral inlet pumping station.

scholarly journals Research on Parametric Design of Hydraulic Retarder Based on Multi-Field Coupling of Heat, Fluid and Solid

2015 ◽  
Vol 9 (1) ◽  
pp. 58-64 ◽  
Author(s):  
Kuiyang Wang ◽  
Jinhua Tang ◽  
Guoqing Li
Keyword(s):  
Numerical Simulation ◽  
Parametric Design ◽  
Design Method ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Field Coupling ◽  
Sequential Coupling ◽  
Fluid Coupling ◽  
Hydraulic Retarder

In order to optimize the design method and improve the performance of hydraulic retarder, the numerical simulation of multi-field coupling of heat, fluid and solid is carried out to hydraulic retarder, based on the numerical computation and algorithm of heat-fluid coupling and fluid-solid coupling. The computation models of heat-fluid coupling and fluid-solid coupling of hydraulic retarder are created. The three dimensional model of hydraulic retarder is established based on CATIA software, and the whole flow passage model of hydraulic retarder is extracted on the basis of the three dimensional model established. Based on the CFD calculation and the finite element numerical simulation, the temperature field, stress field, deformation and stress state are analysised to hydraulic retarder in the state of whole filling when the rotate speed is 1600 r/min. In consideration of rotating centrifugal force, thermal stress and air exciting vibration force of blade surface, by using the sequential coupling method, the flow field characteristics of hydraulic retarder and dynamic characteristics of blade structure are analysised and researched based on multi-field coupling of heat, fluid and solid. These provide the theoretical foundation and references for parametric design of hydraulic retarder.

Three-Dimensional Numerical Analysis of Horizontal and Vertical Coalescence of Bubbles at Two Submerged Horizontal Orifices on the Wall

2019 ◽  
Author(s):  
Z. P. Li ◽  
L. Q. Sun ◽  
X. L. Yao ◽  
Y. Piao
Keyword(s):  
Numerical Simulation ◽  
Internal Pressure ◽  
Three Dimensional ◽  
Ventilation Rate ◽  
Smoothing Technique ◽  
Dimensional Model ◽  
Mesh Smoothing ◽  
Three Dimensional Model ◽  
Coalescence Time ◽  
Ventilation Rates

Abstract In the process of bubbling from two submerged adjacent orifices, bubbles coalescence becomes inevitable. But the study of the evolution and interaction of bubbles from submerged orifices is little, especially numerical simulation. In this paper, combined with mesh smoothing technique, mesh subdivision technique and the technique of axisymmetric coalescence and 3D coalescence, a three-dimensional model of bubbles coalescence at two submerged adjacent orifices on the wall is established by the boundary element method. Then, numerical simulations were carried out for horizontal and vertical coalescence before detachment. Finally, by changing the ventilation rate and the Froude number, the effects of different ventilation rates and buoyancy on the process of bubbles coalescence at two adjacent orifices were investigated. The results show that for horizontal coalescence, the effect of ventilation rate is more pronounced than buoyancy. As the ventilation rate increases or the influence of buoyancy is decreased, the amplitude of internal pressure fluctuation of the bubble decreases and the coalescence time decreases. For vertical coalescence, the effect of buoyancy is more pronounced than ventilation rate. With the influence of buoyancy is decreased, the vertical coalescence time is increased, the internal pressure of the bubble is decreased. The influence of ventilation rate is similar to that of horizontal coalescence.

scholarly journals A quasi three dimensional model of water flow in the subsurface of Milano (Italy): the stationary flow

2000 ◽  
Vol 4 (1) ◽  
pp. 113-124 ◽  
Author(s):  
M. Giudici ◽  
L. Foglia ◽  
G. Parravicini ◽  
G. Ponzini ◽  
B. Sincich
Keyword(s):  
Water Table ◽  
Water Demand ◽  
Three Dimensional ◽  
Stationary Flow ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Predictive Tool ◽  
Aquifer System ◽  
Conservative Finite Difference Scheme ◽  
Comparison Of The Results

Abstract. A quasi three-dimensional model is developed to simulate the behaviour of the aquifer system which is the resource of drinkable water for the town of Milano (Italy). Non continuous semipermeable layers locally separate permeable levels in a multilayered system, consisting of a phreatic and three confined aquifers. The numerical model is a conservative finite difference scheme based on the discretisation of the water balance equation for stationary flow. The grid spacing is 500 m and has been chosen, taking into account the distribution of the data in an area of about 400 km2. The model has been calibrated with a "trial and error" procedure, by comparison of the results of the model with the observations for three years (1950, 1974 and 1982) which correspond to different flow situations. Once calibrated, the model has been used as a predictive tool, to forecast the behaviour of the aquifer system for other years of the 20th century; the comparison between the model forecasts and observations is good. The model is capable of describing both the strong drawdown of the water table in the 1970s, when the water demand for domestic and industrial needs was very high, and the rise of the water table in the 1990s, when water extraction decreased. The results of the model confirm that the phreatic level is controlled largely by the local extraction of water; moreover, the aquifer system reacts to an increasing water demand with a small increase of the inflow and with a strong decrease of the outflow from its boundaries.

Numerical Simulation on the Liquid Metal Flow of the Acceleration Phase in the Shot Sleeve of Cold Chamber Die Casting Process

2007 ◽  
Vol 561-565 ◽  
pp. 1801-1804
Author(s):  
Jie Yang ◽  
Lang Yuan ◽  
Shou Mei Xiong ◽  
Bai Cheng Liu
Keyword(s):  
Numerical Simulation ◽  
Liquid Metal ◽  
Metal Flow ◽  
Three Dimensional ◽  
Great Influence ◽  
Casting Process ◽  
Shot Sleeve ◽  
Three Dimensional Model ◽  
Acceleration Phase ◽  
Fill Ratio

Slow shot velocity and its acceleration phase in the shot sleeve have great influence on the flow pattern of the liquid metal in the shot sleeve. In this paper, a three-dimensional model based on the SOLA-VOF algorithm was developed and used to simulate the flow of melt in the shot sleeve. The mathematical model was verified by water analog experiments with constant plunger velocities. Based on numerical simulation results, the influences of the plunger acceleration on the wave profile of the liquid metal in the shot sleeve under different fill ratios and sleeve diameters were investigated. The results indicated that in order to avoid air entrapment in the shot sleeve, the optimal acceleration value to the critical slow shot velocity increases with the increase of the fill ratio, and the range of suitable acceleration becomes wider as well. With the same fill ratio, the value of suitable acceleration rises as the plunger diameter increases.

Numerical simulation of three-dimensional airflow in a novel dual-feed rotor spinning box

2016 ◽  
Vol 88 (3) ◽  
pp. 237-253 ◽  
Author(s):  
Nicholus Tayari Akankwasa ◽  
Huiting Lin ◽  
Yuze Zhang ◽  
Jun Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Internal Flow ◽  
Velocity Variation ◽  
Positive Pressure ◽  
Three Dimensional Model ◽  
Air Velocity ◽  
Rotor Spinning ◽  
Pressure Profiles

In order to regulate turbulence strength and determine airflow characteristics in a new dual-feed rotor spinning unit, the internal flow field is investigated. A computational fluid dynamics technique is employed to numerically study the three-dimensional model of the internal airflow in the new design. The effects of air velocity variation on turbulence strength, negative pressure, Re, and wall pressure distribution are investigated based on simulation data and previous studies. The results show that the turbulence strength and Re increased with increase in inlet air velocity. Pressure profiles inside the rotor varied significantly with positive pressure observed at the channel exits. Minimal inlet velocity maintains the flow field in the rotor interior below 100 m/s, which gives the ideal turbulence required to minimize yarn quality deterioration. The dual-feed rotor spinning unit showed more orderly streamline patterns with fewer vortices compared to the conventional one. The numerical simulation can provide insights on airflow studies and some guidelines for future prototyping and experiments to further improve the new design.

Numerical investigations of vortex flows and vortex suppression schemes in a large pumping-station sump

2011 ◽  
Vol 225 (6) ◽  
pp. 1459-1480 ◽  
Author(s):  
X L Tang ◽  
F J Wang ◽  
Y J Li ◽  
G H Cong ◽  
X Y Shi ◽  
...  
Keyword(s):  
Free Surface ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Complex Nature ◽  
Stable Operation ◽  
Vortex Flows ◽  
Pumping Station ◽  
Pump Station ◽  
Pump Sump ◽  
Under Construction

This work uses a commercial computational fluid dynamics code to predict three-dimensional (3D) vortex flows in a large centrifugal-pump station under construction in China and proposes relevant vortex-eliminating schemes. Because of the complex nature of the vortex flows in sumps, different turbulence models, namely, standard k–ε, re-normalization group k–ε and realizable k–ε models, are first used to investigate their feasibility in predicting flows in a small physical model of an open pump sump, and various vortex streamlines and strength in the sump are predicted, analysed, and compared with the experimental data. The comparisons show that the realizable k–ε model predicts the position and strength of free-surface, sidewall-attached, and floor-attached vortices more accurately than the other two models. Then, the realizable k–ε model is used here to investigate 3D vortex flows in a large pumping-station sump. All the various vortices, such as free-surface, wall-attached vortices, are successfully predicted. Thus, based on the information of location, shape, size, and strength of the calculated vortices, three types of vortex-eliminating devices are proposed and their corresponding vortex suppression effects are analysed. These results will be used as reference for the safe and stable operation of the Hui–Nan–Zhuang pumping station in the future.

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