scholarly journals Discharge capacity evaluation and hydraulic design of a piano key weir

2018 ◽  
Vol 19 (3) ◽  
pp. 871-878 ◽  
Author(s):  
Xinlei Guo ◽  
Zhiping Liu ◽  
Tao Wang ◽  
Hui Fu ◽  
Jiazhen Li ◽  
...  
Keyword(s):  
Discharge Capacity ◽  
Complex Geometry ◽  
Unit Discharge ◽  
Labyrinth Weir ◽  
Capacity Evaluation ◽  
Hydraulic Design ◽  
New Type ◽  
Multiparameter Optimization ◽  
Piano Key Weir ◽  
New Formula

Abstract A piano key weir (PKW) is a new type of labyrinth weir that increases the unit discharge at the unregulated spillway inlet of the weir. It is considered to be an important structure in water supply and drainage systems. However, its complex geometry makes it difficult to achieve an optimal hydraulic design, and only a few design equations and criteria are available. This study investigates the discharge capacity of a PKW and evaluates the characteristics of its discharge using various sources of experimental data from a database. First, previously proposed discharge capacity formulas are summarized and analyzed. Then, a new formula that integrates the existing test data with the results of dimensional analysis and multiparameter optimization is proposed. The weir characteristics are evaluated using the proposed formula and a mathematical model. The results show that both the proposed formula and numerical model are promising approaches to evaluate the discharge capacity of an A-type PKW and can guide its design.

scholarly journals Sodium Metasilicate Cemented Analogue Material and Its Mechanical Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Songlin Yue ◽  
Yanyu Qiu ◽  
Pengxian Fan ◽  
Pin Zhang ◽  
Ning Zhang
Keyword(s):  
Complex Geometry ◽  
Sodium Metasilicate ◽  
Raw Material ◽  
Fine Aggregate ◽  
Regression Equations ◽  
Deformation And Failure ◽  
Orthogonal Experiments ◽  
Low Modulus ◽  
New Type ◽  
The Relationship

Analogue material with appropriate properties is of great importance to the reliability of geomechanical model test, which is one of the mostly used approaches in field of geotechnical research. In this paper, a new type of analogue material is developed, which is composed of coarse aggregate (quartz sand and/or barite sand), fine aggregate (barite powder), and cementitious material (anhydrous sodium silicate). The components of each raw material are the key influencing factors, which significantly affect the physical and mechanical parameters of analogue materials. In order to establish the relationship between parameters and factors, the material properties including density, Young’s modulus, uniaxial compressive strength, and tensile strength were investigated by a series of orthogonal experiments with hundreds of samples. By orthogonal regression analysis, the regression equations of each parameter were obtained based on experimental data, which can predict the properties of the developed analogue materials according to proportions. The experiments and applications indicate that sodium metasilicate cemented analogue material is a type of low-strength and low-modulus material with designable density, which is insensitive to humidity and temperature and satisfies mechanical scaling criteria for weak rock or soft geological materials. Moreover, the developed material can be easily cast into structures with complex geometry shapes and simulate the deformation and failure processes of prototype rocks.

Performance of rectangular labyrinth weir- an experimental and numerical study

2022 ◽  
Author(s):  
Mosbah Ben Said ◽  
Ahmed Ouamane
Keyword(s):  
Discharge Capacity ◽  
Numerical Study ◽  
Flow Behavior ◽  
Rectangular Channel ◽  
Experimental Models ◽  
Absolute Relative Error ◽  
Labyrinth Weir ◽  
Specific Discharge ◽  
Labyrinth Weirs ◽  
Good Agreement

Abstract Labyrinth weirs are commonly used to increase the capacity of existing spillways and provide more efficient spillways for new dams due to their high specific discharge capacity compared to the linear weir. In the present study, experimental and numerical investigation was conducted to improve the rectangular labyrinth weir performance. In this context, four configurations were tested to evaluate the influence of the entrance shape and alveoli width on its discharge capacity. The experimental models, three models of rectangular labyrinth weir with rounded entrance and one with flat entrance, were tested in rectangular channel conditions for inlet width to outlet width ratios (a/b) equal to 0.67, 1 and 1.5. The results indicate that the rounded entrance increases the weir efficiency by up to 5%. A ratio a/b equal to 1.5 leads to an 8 and 18% increase in the discharge capacity compared to a/b ratio equal to 1 and 0.67, respectively. In addition, a numerical simulation was conducted using the opensource CFD OpenFOAM to analyze and provide more information about the flow behavior over the tested models. A comparison between the experimental and numerical discharge coefficient was performed and good agreement was found (Mean Absolute Relative Error of 4–6%).

A Friction-Enhanced Tuned Ring Damper for Bladed Disks

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Andrea Lupini ◽  
Bogdan I. Epureanu
Keyword(s):  
Energy Transfer ◽  
Relative Motion ◽  
Natural Frequencies ◽  
Complex Geometry ◽  
High Fidelity ◽  
Frictional Contacts ◽  
New Type ◽  
Frictional Interface ◽  
Host Structure ◽  
Tuned Vibration Absorber

Abstract This paper introduces a new type of damper for turbomachinery blisks. The major pitfalls of the damper concepts currently employed are two: the low level of relative motion that is available at the damper attachment location, and the inability to control the preload at the frictional interface. To address these issues, the proposed damper is designed as a tuned vibration absorber (TVA), which allows energy transfer from the blades to the damper provided that the natural frequency of the damper is close to that of the host structure. Thanks to the enhanced energy transfer, the damper can experience increased relative motion. Frictional contacts are then included to dissipate the energy transferred to the damper. The damper structure must be stiff enough to withstand centrifugal loading without affecting the preload too much. However, it also must be compliant to make sure that its natural frequencies can match the ones of the host structure. For this reason, the proposed damper involves a complex geometry that is stiff in the radial direction and softer in the circumferential direction, which is the direction of the relative motion. A model of the damper is created to damp the vibration of a realistic blisk. The effectiveness of the damper is investigated using high fidelity finite element (FE) models. The frequency response of the system is obtained to analyze the effectiveness of the proposed design. Preliminary results show the potential of this technology for structures with such low damping.

A New Type of X-Ray Diffractometer with Cooperating Robots for Residual Stress Analysis on Large Components

2006 ◽  
Vol 524-525 ◽  
pp. 749-754 ◽  
Author(s):  
Roland Hessert ◽  
Wilhelm Satzger ◽  
Alfried Haase ◽  
Achim Schafmeister
Keyword(s):  
Complex Geometry ◽  
Industrial Applications ◽  
Measuring System ◽  
X Ray ◽  
Material Condition ◽  
New Type ◽  
Cooperating Robots ◽  
Aero Engines ◽  
Reference Measurements ◽  
Engine Components

For industrial applications concerning the nondestructive characterization of the nearsurface material condition in terms of residual stresses, work hardening, phase transformation and formation of reaction compounds there is a strong demand for X-ray diffraction measurements on large components with complex geometry. Because many regions of interest on these components are not accessible with conventional laboratory or even mobile X-ray diffractometers, a novel center- free diffractometer with two cooperating robots named "Charon XRD" has been developed at MTU Aero Engines. Using a special optical measuring system to synchronize the two six-axis robots it was possible to achieve positioning accuracies that are comparable to those of conventional stationary diffractometers. This paper describes the design and functionality of Charon XRD and presents calibration and reference measurements, along with first measurements on aero-engine components.

scholarly journals Effect of Corner Shape on Hydraulic Performance of One-Cycle Rectangular Labyrinth Weirs

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 117
Author(s):  
Omed S. Q. Yousif ◽  
Moses Karakouzian
Keyword(s):  
Discharge Capacity ◽  
Hydraulic Performance ◽  
Acute Angle ◽  
Effective Length ◽  
Hydraulic Efficiency ◽  
Labyrinth Weir ◽  
Rounded Corner ◽  
Side Walls ◽  
The One ◽  
Labyrinth Weirs

The hydraulic performance of rectangular labyrinth weirs has been investigated by many researchers, however, the effects of the corner shape on the hydraulic performance of rectangular labyrinth weirs have not been addressed in the current literature. Accordingly, this experimental study aims to explore the effect of the corner shape of on discharge efficiency of rectangular labyrinth weirs. Five flat-crested rectangular labyrinth weirs, with five different corner shapes, were made of High-Density Polyethylene Plastic (HDPE) and tested in a rectangular flume. Under different overflow discharges, the discharge coefficients for the rectangular labyrinth weirs were determined. The results showed that the shape of corners for rectangular labyrinth weirs was an effective factor. For example, rounding or beveling the corners can significantly increase the discharge capacity of the rectangular labyrinth weirs. However, the rounded corner shape was slightly better than the beveled corner shape. Among all labyrinth weir models tested in this study, the rectangular labyrinth weir with a semi-circular apex showed the highest hydraulic efficiency, while the one with an acute-angle corner shape showed the lowest hydraulic efficiency. For the rectangular labyrinth weir having a semi-circular shape, although the original effective length reduced by about 14%, the discharge coefficient, CL, increased by 16.7% on average. For the rectangular labyrinth weir that has an acute-angle corner shape, although the effective length (LC) of the weir increased by 23%, its discharge capacity decreased by 35.2% on average. Accordingly, improper folding of the side-walls of the rectangular labyrinth weir led to a significant reduction in the weir’s hydraulic performance.

scholarly journals Biological inter-dependencies in 3D printing: Larvae scaffold excavation of high filigree clay structures

2021 ◽  
Author(s):  
◽  
Mark Bagley
Keyword(s):  
3D Printing ◽  
Complex Geometry ◽  
Ceramic Materials ◽  
Shell Structures ◽  
Secondary Material ◽  
Novel Approach ◽  
Design And Manufacturing ◽  
New Type ◽  
Technological Constraints ◽  
The Relationship

<p>Ceramic 3D printing has emerged in recent years as a new method for working with age-old material, a blend of the digital and analog that breeds a new type of artisan. Working with clay in an FDM extrusion system presents a number of challenges due to the nature of the material, restricting the forms that can be produced to rudimentary levels of ornament and shape. This research tackles the issue of resolution and thickness when creating and designing shell structures from ceramic materials, notably when 3D printing is used for complex geometry. This research aims to navigate these material and technological constraints by designing a novel approach to support scaffolds using a secondary material. This secondary material serves as an organic encasement for the ceramic object, and nature is treated as a co-collaborator in the excavation and controlled curing of a high filigree clay structure. By introducing edible bio matter and/or cellulose solutions, this encourages a new relationship with nature as a tool and co-author, becoming a stakeholder in the final result. This research examines the relationship between human, machine, and nature in the design and manufacturing of products.</p>

scholarly journals Biological inter-dependencies in 3D printing: Larvae scaffold excavation of high filigree clay structures

2021 ◽  
Author(s):  
◽  
Mark Bagley
Keyword(s):  
3D Printing ◽  
Complex Geometry ◽  
Ceramic Materials ◽  
Shell Structures ◽  
Secondary Material ◽  
Novel Approach ◽  
Design And Manufacturing ◽  
New Type ◽  
Technological Constraints ◽  
The Relationship

<p>Ceramic 3D printing has emerged in recent years as a new method for working with age-old material, a blend of the digital and analog that breeds a new type of artisan. Working with clay in an FDM extrusion system presents a number of challenges due to the nature of the material, restricting the forms that can be produced to rudimentary levels of ornament and shape. This research tackles the issue of resolution and thickness when creating and designing shell structures from ceramic materials, notably when 3D printing is used for complex geometry. This research aims to navigate these material and technological constraints by designing a novel approach to support scaffolds using a secondary material. This secondary material serves as an organic encasement for the ceramic object, and nature is treated as a co-collaborator in the excavation and controlled curing of a high filigree clay structure. By introducing edible bio matter and/or cellulose solutions, this encourages a new relationship with nature as a tool and co-author, becoming a stakeholder in the final result. This research examines the relationship between human, machine, and nature in the design and manufacturing of products.</p>

scholarly journals Introducing the T-shaped weir: a new nonlinear weir

2021 ◽  
Author(s):  
Behzad Noroozi ◽  
Jalal Bazargan ◽  
Akbar Safarzadeh
Keyword(s):  
Discharge Coefficient ◽  
Vertical Wall ◽  
Hydraulic Performance ◽  
Height Ratio ◽  
Maximum Increase ◽  
Labyrinth Weir ◽  
Numerical Tests ◽  
Vertical Walls ◽  
Piano Key Weir ◽  
3D Software

Abstract In the present study, a new nonlinear weir called the T-Shaped Weir (TSW), which is a combination of the Labyrinth Weir (LW) and the Piano Key Weir (PKW), was introduced, and its hydraulic performance was compared with the PKW. Based on the presence of the vertical walls at the inlet key, outlet key, or both keys, the TSW weirs were classified as type A, B, and C weirs, respectively. The flow pattern of different TSW cases was analyzed, and the discharge coefficient curves were provided. Furthermore, to accurately study the hydrodynamics of the tested weirs, the 3D numerical simulations were performed using the FLOW-3D software. The results showed that inserting a vertical wall at the upstream of the outlet keys (C-TSW type) has a negligible effect on the hydraulic performance of the PKW. A maximum increase of 16% occurred in the discharge coefficient of the B-TSW in comparison to the PKW, and up to a head to height ratio (Ht/p) of 0.45, effect of the vertical wall on increasing the performance of the B-TSW was maintained. Based on the experimental and numerical tests, the optimal height ratio of the vertical wall (Pd/P) in B-TSW with highest discharge capacity was determined equal to 0.4.

An analytical approach for Piano Key weir hydraulic design

2013 ◽  
pp. 131-138 ◽  
Author(s):  
O Machiels ◽  
B Dewals ◽  
P Archambeau ◽  
M Pirotton ◽  
S Erpicum
Keyword(s):  
Analytical Approach ◽  
Hydraulic Design ◽  
Piano Key Weir

A new type of cyclic silicone additive for improving the energy density and power density of Li–O2 batteries

2018 ◽  
Vol 6 (16) ◽  
pp. 7221-7226 ◽  
Author(s):  
Chunguang Chen ◽  
Xiang Chen ◽  
Xiuhui Zhang ◽  
Liangyu Li ◽  
Congcong Zhang ◽  
...  
Keyword(s):  
Energy Density ◽  
Power Density ◽  
Discharge Capacity ◽  
Rate Capability ◽  
Electrolyte Additive ◽  
Silicone Additive ◽  
New Type

In this work, a novel electrolyte additive, octamethylcyclotetrasiloxane (OMTS), is applied to Li–O2 batteries to increase their practical discharge capacity and also their rate capability.

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