scholarly journals Hydraulic Advantage of Piano-key Weir Over Ogee Weir

2019 ◽  
Vol 9 (2S2) ◽  
pp. 23-25
Keyword(s):  
Laboratory Investigation ◽  
Hydraulic Structure ◽  
Hydraulic Performance ◽  
Hydraulic Efficiency ◽  
Experiment Data ◽  
Limited Knowledge ◽  
Piano Key Weir

The piano-key weir is a new encouraging hydraulic structure yet to become a widespread usage due to limited knowledge of the hydraulic performance. A laboratory investigation on the hydraulic efficiency of the piano-key weir was compared with that of an ogee weir. The experiment data confirmed that the piano-key weir discharged more than ogee weir for the same upstream head. However, the coefficient discharge of the piano-key weir is extremely low compared to the ogee weir.

scholarly journals Energy Dissipation of Type a Piano Key Weirs

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1253
Author(s):  
Kam R. Eslinger ◽  
Brian M. Crookston
Keyword(s):  
Energy Dissipation ◽  
Hydraulic Structure ◽  
Type A ◽  
Residual Energy ◽  
Published Data ◽  
Hydraulic Efficiency ◽  
Support Design ◽  
Small Footprint ◽  
Piano Key Weir ◽  
Labyrinth Weirs

A Piano Key weir (PK weir) is a nonlinear, labyrinth-type weir well suited for rehabilitation projects due to a relatively small footprint and the ability to pass large discharges for lesser upstream-head values when compared with other weir types. A critical component of a hydraulic structure is the energy-dissipative properties. Currently, information and guidance is limited, with previous energy dissipation studies of PK weirs primarily of specific projects. Therefore, to document and quantify energy dissipation, four laboratory-scale Type A PK weir models with different width ratios (Wi/Wo) were studied, with 255 tests comprising this new dataset, along with detailed observations of the flow field. Results were compared to existing published data regarding energy dissipation downstream of trapezoidal and rectangular labyrinth weirs. To support design efforts, two equations, both functions of head-water ratio (H/P) and Wi/Wo, are proposed to predict the relative residual energy downstream of PK weirs. The energy dissipation of PK weirs is largest at low flows and decreases in a logarithmic-like manner as flow increases. PK weirs with increased hydraulic efficiency, caused by an increase in Wi/Wo, resulted in slightly smaller energy dissipation values within the range 0.2 ≤ H/P ≤ 0.8. The energy dissipation of PK weirs was found to be relatively constant, independent of Wi/Wo, and in the ranges 0.07 ≤ H/P ≤ 0.2 and 0.8 ≤ H/P ≤ 0.95.

Hydraulic Design of Inlet Guide Vane and its Full Flow Passage Numerical Simulation on Centrifugal Pump

2014 ◽  
Author(s):  
Hucan Hou ◽  
Yongxue Zhang ◽  
Zhenlin Li ◽  
Xin Zhou ◽  
Zizhe Wang
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Guide Vane ◽  
Hydraulic Performance ◽  
Design Flow ◽  
Inlet Guide Vane ◽  
Hydraulic Efficiency ◽  
Flow Passage ◽  
Setting Angle ◽  
Hydraulic Design

In order to effectively improve hydraulic performance of centrifugal pump on off-conditions, the hydraulic design of inlet guide vane (IGV) was completed by adopting two dimensional theory in-house code based on one kind of IS series of centrifugal pump, which can achieve pre-whirl regulation of centrifugal pump. During design process the trailing edge of vane is assumed as equal velocity moment condition, and the distribution of vane setting angle along meridional streamline is also given as a quartic function firstly, the camber line is then drawn by point-by-point integration method and thickened at both sides along circumferential direction. With local vortex dynamics diagnosis theory, the optimal improvement of vane space shape can be finished by adjusting the design parameters of vane setting angle distribution coefficient ap. The full flow passage numerical simulations of centrifugal pump with IGV device are completed to analyze the influence of pre-whirl regulation on hydraulic performance of centrifugal pump under various pre-whirl angles. The results show that the pre-whirl regulation can improve the hydraulic performance of centrifugal pump on off-conditions. Under the positive pre-whirl regulation conditions, the best efficient point shift to small flow rate zone, and under the negative pre-whirl regulation conditions it moves to large flow rate zone. Compared with the pump without IGV device at the same flow rate condition of 0.8Q (Q the design flow rate), the hydraulic efficiency of centrifugal pump with IGV device improves obviously and reaches up to 1.43%. Meanwhile compared with that installed with the straight vanes designed based on the traditional theory, the inner flow field of centrifugal pump with the designed vanes improves and the overall hydraulic efficiency of centrifugal pump is somewhat increased.

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 Optimization of a Centrifugal Boiler Circulating Pump's Casing Based on CFD and FEM Analyses

2014 ◽  
Vol 6 ◽  
pp. 532892 ◽  
Author(s):  
Zhigang Zuo ◽  
Shuhong Liu ◽  
Yizhang Fan ◽  
Yulin Wu
Keyword(s):  
Performance Evaluation ◽  
Fatigue Strength ◽  
Economic Efficiency ◽  
Manufacturing Process ◽  
Hydraulic Performance ◽  
Point Of View ◽  
Hydraulic Efficiency ◽  
Working Temperature ◽  
Sealing Ring ◽  
Cfd Analyses

It is important to evaluate the economic efficiency of boiler circulating pumps in manufacturing process from the manufacturers' point of view. The possibility of optimizing the pump casing with respect to structural pressure integrity and hydraulic performance was discussed. CFD analyses of pump models with different pump casing sizes were firstly carried out for the hydraulic performance evaluation. The effects of the working temperature and the sealing ring on the hydraulic efficiency were discussed. A model with casing diameter of 0.875 D40 was selected for further analyses. FEM analyses were then carried out on different combinations of casing sizes, casing wall thickness, and materials, to evaluate its safety related to pressure integrity, with respect to both static and fatigue strength analyses. Two models with forging and cast materials were selected as final results.

scholarly journals Hydraulic residence time and iron removal in a wetland receiving ferruginous mine water over a 4 year period from commissioning

2010 ◽  
Vol 62 (8) ◽  
pp. 1937-1946 ◽  
Author(s):  
F. M. Kusin ◽  
A. P. Jarvis ◽  
C. J. Gandy
Keyword(s):  
Residence Time ◽  
Mine Water ◽  
Flow Distribution ◽  
Hydraulic Performance ◽  
Slight Reduction ◽  
Hydraulic Efficiency ◽  
Treatment Wetland ◽  
Hydraulic Residence Time ◽  
Mine Waters ◽  
The Uk

Analysis of residence time distribution (RTD) has been conducted for the UK Coal Authority's mine water treatment wetland at Lambley, Northumberland, to determine the hydraulic performance of the wetland over a period of approximately 4 years since site commissioning. The wetland RTD was evaluated in accordance with moment analysis and modelled based on a tanks-in-series (TIS) model to yield the hydraulic characteristics of system performance. Greater hydraulic performance was seen during the second site monitoring after 21 months of site operation i.e. longer hydraulic residence time to reflect overall system hydraulic efficiency, compared to wetland performance during its early operation. Further monitoring of residence time during the third year of wetland operation indicated a slight reduction in hydraulic residence time, thus a lower system hydraulic efficiency. In contrast, performance during the fourth year of wetland operation exhibited an improved overall system hydraulic efficiency, suggesting the influence of reed growth over the lifetime of such systems on hydraulic performance. Interestingly, the same pattern was found for iron (which is the primary pollutant of concern in ferruginous mine waters) removal efficiency of the wetland system from the second to fourth year of wetland operation. This may therefore, reflect the maturity of reeds for maintaining efficient flow distribution across the wetland to retain a longer residence time and significant fractions of water involved to enhance the extent of treatment received for iron attenuation. Further monitoring will be conducted to establish whether such performance is maintained, or whether efficiency decreases over time due to accumulation of dead plant material within the wetland cells.

Evaluation of hydraulic performance indices for retention ponds

2015 ◽  
Vol 72 (1) ◽  
pp. 10-21 ◽  
Author(s):  
Arash Farjood ◽  
Bruce W. Melville ◽  
Asaad Y. Shamseldin ◽  
Keith N. Adams ◽  
Sher Khan
Keyword(s):  
Hydraulic Performance ◽  
Hydraulic Efficiency ◽  
Hydraulic Analysis ◽  
Performance Indices ◽  
Sediment Retention ◽  
Retention Pond ◽  
Retention Ponds ◽  
Sediment Retention Ponds ◽  
Moment Index ◽  
Selection Of

Abstract Comprehensive hydraulic analysis of sediment retention ponds is commonly achieved through interpretation of residence time distribution and derivation of indices associated with short-circuiting and mixing. However, the availability of various indices indicates the need for careful selection of the most appropriate indices. This study compares some of the commonly used hydraulic performance indices, together with a new short-circuiting index, τ5, for five different flow regimes in a model sediment retention pond. The results show that τ5 was the best measure for short-circuiting. Among the mixing indices, only the Morril index correctly represented the physical behaviour of the experiments. In addition, two hydraulic efficiency indices, λ and a moment index (MI) were assessed and showed a good correlation with the short-circuiting and mixing indices, but MI was more reproducible than λ. Based on these results, this study recommends using τ5, Morril index and MI for analysis of hydraulic performance in sediment retention ponds.

Hydraulic performance of damaged-end corrugated steel pipe culverts

2008 ◽  
Vol 35 (9) ◽  
pp. 918-924 ◽  
Author(s):  
J. A. Kells
Keyword(s):  
Discharge Capacity ◽  
Discharge Coefficient ◽  
Hydraulic Structure ◽  
Hydraulic Performance ◽  
Steel Pipe ◽  
Simple Type ◽  
Thin Wall ◽  
Modes Of Operation ◽  
Hydraulic Impact ◽  
Loss Coefficients

Culverts are a common and physically simple type of hydraulic structure, which are often fabricated as circular, corrugated steel pipe (CSP) sections. Because of the relatively thin wall of CSP, the ends of such pipe are frequently in a damaged condition. It is hypothesized that the hydraulic impact of the damage is often quite significant, resulting in reduced discharge capacity and (or) increased headwater ponding. The study reported in this paper was focused on an evaluation of the hydraulic impact of various levels of damage to the end sections of a culvert operating under either inlet or outlet control. In general, it was found that, for end damage deformations up to 1/4 of the pipe diameter, the discharge coefficient is reduced by approximately 10%, while the loss coefficients are increased by about 48% and 35% for inlet and outlet control modes of operation, respectively. For greater degrees of damage, the hydraulic performance is considerably worse.

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.

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