Units Commitment Optimization of Pumping Station Based on Velocity Uniformity Analysis

2013 ◽  
Vol 805-806 ◽  
pp. 1720-1723
Author(s):  
Xing Liang
Keyword(s):  
Experimental Data ◽  
Velocity Distribution ◽  
Flow Pattern ◽  
Unit Commitment ◽  
Flow Characteristics ◽  
Optimal Operation ◽  
Operation Strategy ◽  
Turbulent Model ◽  
Pumping Station ◽  
Better Than

The Realizable k-ε turbulent model is employed to simulate the flow pattern in forebay of pumping station, and the precision of simulated results is verified by experimental data. And then the flow pattern of the different unit commitments is simulated to acquire the flow characteristics in forebay, such as circulating flow and velocity distribution, and the velocity uniformity of forebay is analyzed to search the optimal units commitment. The research results show that: under the different unit commitment, the characteristics of flow in forebay is so different that the effect of the diversion piers is not always advantageous; comparing the velocity uniformity, the optimal operation strategy is to try to operate the middle pumps, and the operation strategy of operating pumps on both sides is better than that of opening pumps on one side.

Study of Flow Characteristics of Oil and Water in the Process of Stirring

2013 ◽  
Vol 353-356 ◽  
pp. 3190-3193
Author(s):  
Zong Rui Hao ◽  
Juan Xu ◽  
Hai Yan Bie ◽  
Zhong Hai Zhou
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
Cross Section ◽  
Radial Flow ◽  
Flow Characteristics ◽  
Stirred Tank ◽  
Turbulent Model ◽  
Vof Model ◽  
Circular Flows ◽  
Oil Water

To study the flow pattern in the process of oil-water stirring in three paddle stirring tank, RNG k-ε turbulent model and VOF model are adopted to simulate the flow field at different time in the stirred tank with the baffle. The results showed that, in the stirring process, inverted cone manifold was formed in the center of the stirring shaft. The stratified area was formed in the baffle and gradually transported to the bottom of the tank. The two circular flows were formed among three groups of blades. And the axially acting of the fluid was strong, which made homogeneous stirring in the stirred tank. At the same time the radial flow of the cross-section inside the tank increased because of the baffle.

scholarly journals Prototype Observation of Flow Characteristics in an Inclined-Tube Settling Tank for Fine Sandy Water Treatment

2020 ◽  
Vol 10 (10) ◽  
pp. 3586
Author(s):  
Keyuan Wang ◽  
Yunkai Li ◽  
Shumei Ren ◽  
Peiling Yang
Keyword(s):  
Shear Stress ◽  
Velocity Distribution ◽  
Flow Pattern ◽  
Turbulence Intensity ◽  
Reynolds Shear Stress ◽  
Settling Tank ◽  
Flow Characteristics ◽  
Settlement Area ◽  
Flow Adjustment ◽  
Inclined Tube

Clarifying the flow characteristics in the settling tank is the foundation for the design optimization and efficiency improvement of sediment removal. However, few research works have been undertaken on the precise observation of the flow movement in the tank. For this purpose, research into an inclined-tube settling tank for the water-sediment separation of the Yellow River was carried out. An acoustic Doppler velocimeter (ADV) was utilized to measure the velocity distribution in the tank. The dimensionless turbulence intensity and dimensionless Reynolds shear stress distribution were obtained subsequently. It was found that the velocity distribution in the stable settlement area (SSA) and the settlement area with inclined tubes (ISA) was uniform. The turbulence intensity and Reynolds shear stress in the tank were beneficial to the formation of the flocs and the subsequent acceleration of the sediment settling. The flow pattern could be significantly improved by the flow adjustment board and the inclined tubes. However, the inlet, the baffle and the overflow weir in the tank had negative effects on the flow pattern. The results enhanced our understanding of the flow characteristics in the inclined-tube settling tank and indicated a direction for optimizing the tank structure and improving the settling efficiency.

Numerical Calculation of Turbulent Channel Flow with Porous Ribs

2010 ◽  
Vol 26 (1) ◽  
pp. 15-28 ◽  
Author(s):  
H. C. Chan ◽  
Yaoxin Zhang ◽  
J. M. Leu ◽  
Y.-S. Chen
Keyword(s):  
Experimental Data ◽  
Numerical Calculation ◽  
Flow Characteristics ◽  
Turbulent Channel Flow ◽  
Navier Stokes ◽  
Computational Results ◽  
Turbulent Model ◽  
Outer Flow ◽  
Pitch Ratio ◽  
Porous Property

AbstractThe turbulent flow in a channel with periodic porous ribs on one wall is numerically studied. The numerical model utilizes the Reynolds averaged Navier-Stokes (RANS) equations with a k−ε turbulent model for turbulence closure. Computational results show good agreements with experimental data in flows over a porous rib. The parameter effects, including the pitch ratio PR (1 ∼ 9) and porosity γ (0.4 ∼ 0.6), on flow fields are further examined in detail. Systematic variations of streamline, streamwise and vertical velocities, and turbulent kinetic energy are clearly identified. As to the PR effect, the interaction between outer flow and flow within the cavity is promoted by arranging ribs due to the penetration of the outer flow. Increasing porosity can reduce the downward outer flow by strong flows passing through the porous ribs. The numerical calculations suggest that the flow characteristics for porous ribs are not only a function of the rib geometry, i.e. pitch ratio, but also the porous property, i.e. porosity.

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.

Estimating ink mileage of dry toners in electrophotography

TAPPI Journal ◽  
2013 ◽  
Vol 12 (3) ◽  
pp. 9-14
Author(s):  
RENMEI XU ◽  
CELESTE M. CALKINS
Keyword(s):  
Experimental Data ◽  
Curve Fitting ◽  
Graphite Furnace ◽  
Atomic Absorption Spectrometer ◽  
Density Region ◽  
Coated Papers ◽  
Graphite Furnace Atomic Absorption ◽  
S Model ◽  
Better Than ◽  
Film Weight

This work investigates the ink mileage of dry toners in electrophotography (EP). Four different substrates were printed on a dry-toner color production Xerox iGen3 EP press. The print layout contained patches with different cyan, magenta, yellow, and black tonal values from 10% to 100%. Toner amounts on cyan patches were measured using an analytical method. Printed patches and unprinted paper samples, as well as dry toners, were dissolved in concentrated nitric acid. The copper concentrations in the dissolved solutions were analyzed by a Zeeman graphite furnace atomic absorption spectrometer. Analytical results were calculated to determine the toner amounts on paper for different tonal values. Their corresponding reflection densities were also measured. All data were plotted with OriginPro® 8 software, and four mathematical models were used for curve fitting. It was found that the C-S model fitted the experimental data of the two uncoated papers better than the other three models. None of the four models fitted the experimental data of the two coated papers, while the linear model was found to fit the data well. Linear fitting was the best in the practical density region for the two coated papers. Ink mileage curves obtained from curve fitting were used to estimate how much ink was required to achieve a target density for each paper; hence, the ink mileage was calculated. The highest ink mileage was 3.39 times the lowest ink mileage. The rougher the paper surface, the higher the requirement for ink film weight, and the lower ink mileage. No correlation was found between ink mileage and paper porosity.

scholarly journals Experimental data for the slug two-phase flow characteristics in horizontal pipeline

Data in Brief ◽  
2018 ◽  
Vol 16 ◽  
pp. 527-530 ◽  
Author(s):  
Abdalellah O. Mohmmed ◽  
Mohammad S. Nasif ◽  
Hussain H. Al-Kayiem
Keyword(s):  
Experimental Data ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Two Phase

An Experimental and Analytical Study of Single-Phase Liquid Flow in a Horizontal Well

1997 ◽  
Vol 119 (1) ◽  
pp. 20-25 ◽  
Author(s):  
H. Yuan ◽  
C. Sarica ◽  
S. Miska ◽  
J. P. Brill
Keyword(s):  
Experimental Data ◽  
Friction Factor ◽  
Horizontal Well ◽  
Flow Behavior ◽  
Reynolds Numbers ◽  
Test Facility ◽  
Phase Liquid ◽  
Rate Ratios ◽  
Friction Factor Correlation ◽  
Better Than

A new test facility was designed and constructed to simulate flow in a horizontal well with a single perforation. A total of 635 tests were conducted with Reynolds numbers ranging from 5000 to 60,000 with influx to main rate ratios ranging from 1/5 to 1/100, and also for the no-influx case. The flow behavior in a single-perforation new friction expression for a single-perforation horizontal well was developed. A new simple correlation for the horizontal well friction factor was developed by applying experimental data to the general friction factor expression. The new friction factor correlation and experimental data were compared with the Asheim et al. (1992) data and model, and showed that the new correlation performed better than the Asheim et al. (1992) model.

A multi-time-space scale optimal operation strategy for a distributed integrated energy system

2021 ◽  
Vol 289 ◽  
pp. 116698
Author(s):  
Peng Li ◽  
Zixuan Wang ◽  
Jiahao Wang ◽  
Tianyu Guo ◽  
Yunxing Yin
Keyword(s):  
Energy System ◽  
Optimal Operation ◽  
Operation Strategy ◽  
Space Scale ◽  
Time Space ◽  
Integrated Energy System

Fully Plastic Failure Stresses and Allowable Crack Sizes for Circumferentially Surface Cracked Pipes Subjected to Tensile Loading

2021 ◽  
Author(s):  
Kunio Hasegawa ◽  
David Dvorak ◽  
Vratislav Mares ◽  
Bohumir Strnadel ◽  
Yinsheng Li
Keyword(s):  
Experimental Data ◽  
Bending Moment ◽  
Limit Load ◽  
Tensile Loading ◽  
Crack Size ◽  
Plastic Failure ◽  
Circumferential Crack ◽  
Asme Code ◽  
American Society ◽  
Better Than

Abstract Fully plastic failure stresses for circumferentially surface cracked pipes subjected to tensile loading can be estimated by means of limit load criteria based on the net-section stress approach. Limit load criteria of the first type (labelled LLC-1) were derived from the balance of uniaxial forces. Limit load criteria of the second type are given in Section XI of the ASME (American Society of Mechanical Engineering) Code, and were derived from the balance of bending moment and axial force. These are labelled LLC-2. Fully plastic failure stresses estimated by using LLC-1 and LLC-2 were compared. The stresses estimated by LLC-1 are always larger than those estimated by LLC-2. From the literature survey of experimental data, failure stresses obtained by both types of LLC were compared with the experimental data. It can be stated that failure stresses calculated by LLC-1 are better than those calculated by LLC-2 for shallow cracks. On the contrary, for deep cracks, LLC-2 predictions of failure stresses are fairly close to the experimental data. Furthermore, allowable circumferential crack sizes obtained by LLC-1 were compared with the sizes given in Section XI of the ASME Code. The allowable crack sizes obtained by LLC-1 are larger than those obtained by LLC-2. It can be stated that the allowable crack size for tensile stress depends on the condition of constraint of the pipe, and the allowable cracks given in Section XI of the ASME Code are conservative.

scholarly journals Adaptive Robust Optimization-Based Optimal Operation of Microgrids Considering Uncertainties in Arrival and Departure Times of Electric Vehicles

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2646 ◽  
Author(s):  
Se-Hyeok Choi ◽  
Akhtar Hussain ◽  
Hak-Man Kim
Keyword(s):  
Robust Optimization ◽  
Electric Vehicles ◽  
Unit Commitment ◽  
Renewable Energy Sources ◽  
Market Price ◽  
Optimal Operation ◽  
Worst Case ◽  
Price Signals ◽  
Power Trading ◽  
The Impact

The optimal operation of microgrids is challenging due to the presence of various uncertain factors, i.e., renewable energy sources, loads, market price signals, and arrival and departure times of electric vehicles (EVs). In order to incorporate these uncertainties into the operation model of microgrids, an adaptive robust optimization-based operation method is proposed in this paper. In particular, the focus is on the uncertainties in arrival and departure times of EVs. The optimization problem is divided into inner and outer problems and is solved iteratively by introducing column and constraint cuts. The unit commitment status of dispatchable generators is determined in the outer problem. Then, the worst-case realizations of all the uncertain factors are determined in the inner problem. Based on the values of uncertain factors, the generation amount of dispatchable generators, the amount of power trading with the utility grid, and the charging/discharging amount of storage elements are determined. The performance of the proposed method is evaluated using three different cases, and sensitivity analysis is carried out by varying the number of EVs and the budget of uncertainty. The impact of the budget of uncertainty and number of EVs on the operation cost of the microgrid is also evaluated considering uncertainties in arrival and departure times of EVs.

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