Physical Model Study of Chicago's New Calumet Influent Pumping Station

2009 ◽  
Vol 4 (1) ◽  
Author(s):  
D. Brocard ◽  
M. Garcia ◽  
T. Kunetz ◽  
J. Sobanski ◽  
A. Waratuke ◽  
...  
Keyword(s):  
Physical Model ◽  
Air Entrainment ◽  
Design Guidelines ◽  
Water Levels ◽  
Maintenance Cost ◽  
Optimized Design ◽  
Original Design ◽  
Pumping Station ◽  
Model Study ◽  
Wide Range

A new raw wastewater influent pumping station was designed for the Calumet Water Reclamation Plant in Chicago. The new station could not be designed to be in full compliance with design guidelines of the Hydraulic Institute due to site constraints. Proper operation of the pumping station and optimum operational flexibility are goals for the successful long term performance of the new station. A physical model study was used to identify deficiencies in the original design relative to flow characteristics. The model enabled development of design modifications to address hydraulic flow deficiencies. The optimized design resulted in pump approach flow conditions that provide proper pump performance under a wide range of varying water levels and different combinations of operating pumps and screen channels. Other benefits of the model included improvement in pump efficiency, lack of air entrainment, decreased pump wear, and decreased scour of concrete surfaces. Optimized design also results in operation and maintenance cost savings which, in the long run, will greatly surpass the cost of the physical model study. The required elements to optimize the performance were integrated with the design of the facility, thereby avoiding potentially costly retrofits if the deficiencies had not been mitigated prior to construction.

scholarly journals Two-Dimensional Numerical Modeling of Flow in Physical Models of Rock Vane and Bendway Weir Configurations

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 458
Author(s):  
Drew C. Baird ◽  
Benjamin Abban ◽  
S. Michael Scurlock ◽  
Steven B. Abt ◽  
Christopher I. Thornton
Keyword(s):  
Numerical Modeling ◽  
Physical Model ◽  
Numerical Models ◽  
Hydraulic Performance ◽  
Physical Models ◽  
Protection Measures ◽  
Design Engineers ◽  
Model Study ◽  
Study Results ◽  
Wide Range

While there are a wide range of design recommendations for using rock vanes and bendway weirs as streambank protection measures, no comprehensive, standard approach is currently available for design engineers to evaluate their hydraulic performance before construction. This study investigates using 2D numerical modeling as an option for predicting the hydraulic performance of rock vane and bendway weir structure designs for streambank protection. We used the Sedimentation and River Hydraulics (SRH)-2D depth-averaged numerical model to simulate flows around rock vane and bendway weir installations that were previously examined as part of a physical model study and that had water surface elevation and velocity observations. Overall, SRH-2D predicted the same general flow patterns as the physical model, but over- and underpredicted the flow velocity in some areas. These over- and underpredictions could be primarily attributed to the assumption of negligible vertical velocities. Nonetheless, the point differences between the predicted and observed velocities generally ranged from 15 to 25%, with some exceptions. The results showed that 2D numerical models could provide adequate insight into the hydraulic performance of rock vanes and bendway weirs. Accordingly, design guidance and implications of the study results are presented for design engineers.

Avoiding Sedimentation and Air Entrainment in Pump Sump for Wet Pit Pumping Stations

2015 ◽  
Author(s):  
Raja Abou Ackl ◽  
Andreas Swienty ◽  
Flemming Lykholt-Ustrup ◽  
Paul Uwe Thamsen
Keyword(s):  
Physical Model ◽  
Air Entrainment ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Design Criteria ◽  
Flow Conditions ◽  
Pumping Station ◽  
Pumping Stations ◽  
Pump Sump ◽  
Pump Stations

In many places lifting systems represent central components of wastewater systems. Pumping stations with a circular wet-pit design are characterized by their relatively small footprint for a given sump volume as well as their relatively simple construction technique [1]. This kind of pumping stations is equipped with submersible pumps. These are located in this case directly in the wastewater collection pit. The waste water passes through the pump station untreated and loaded with all kind of solids. Thus, the role of the pump sump is to provide an optimal operating environment for the pumps in addition to the transportation of sewage solids. Understanding the effects of design criteria on pumping station performance is important to fulfil the wastewater transportation as maintenance-free and energy efficient as possible. The design of the pit may affect the overall performance of the station in terms of poor flow conditions inside the pit, non-uniform und disturbed inflow at the pump inlet, as well as air entrainment to the pump. The scope of this paper is to evaluate the impact of various design criteria and the operating conditions on the performance of pump stations concerning the air entrainment to the pump as well as the sedimentation inside the pit. This is done to provide documentation and recommendations of the design and operating of the station. The investigated criteria are: the inflow direction, and the operating submergence. In this context experiments were conducted on a physical model of duplex circular wet pit wastewater pumping station. Furthermore the same experiments were reproduced by numerical simulations. The physical model made of acrylic allowed to visualize the flow patterns inside the sump at various operating conditions. This model is equipped with five different inflow directions, two of them are tangential to the pit and the remaining three are radial in various positions relative to the pumps centerline. Particles were used to enable the investigation of the flow patterns inside the pit to determine the zones of high sedimentation risk. The air entrainment was evaluated on the model test rig by measuring the depth, the width and the length of the aerated region caused by the plunging water jet and by observing the air bubbles entering the pumps. The starting sump geometry called baseline geometry is simply a flat floor. The tests were done at all the possible combinations of inflow directions, submergence, working pump and operating flow. The ability of the numerical simulation to give a reliable prediction of air entrainment was assessed to be used in the future as a tool in scale series to define the scale effect as well as to analyze the flow conditions inside the sump and to understand the air entrainment phenomenon. These simulations were conducted using the geometries of the test setup after generating the mesh with tetrahedral elements. The VOF multiphase model was applied to simulate the interaction of the liquid water phase and the gaseous air phase. On the basis of the results constructive suggestions are derived for the design of the pit, as well as the operating conditions of the pumping station. At the end recommendations for the design and operating conditions are provided.

Physical Model Test of Water Intake Including Huge Pump Station and Drum Screen

2008 ◽  
Author(s):  
Sadegh Barzegar ◽  
Mohammad Banae ◽  
Mohammad Ali Hamed ◽  
Mohammad Qaheri Badr
Keyword(s):  
Physical Model ◽  
Water Intake ◽  
Reverse Flow ◽  
Flow Behavior ◽  
Cross Flow ◽  
Air Entrainment ◽  
Physical Model Test ◽  
Original Design ◽  
Low Velocity ◽  
Pump Station

A physical model, built at an undistorted scale of 1:15 tested the original design of the six drum screen and nineteen cooling water pump intake connected to header bay. The capacity of origin water intake including huge pump station and drum screen is 400,000 m3/hr. The study objectives were to evaluate as-designed screen bay and pump bay performance and to propose design modifications to optimize intake flow conditions with respect to head-losses, uniformity of the approach flow, evenness of pump throat velocity distribution, and free and subsurface vortex formation. The model was built and operated in accordance with froude-number similitude. It allowed accurate representation of complex flow patterns caused by the physical geometry of the approach bay and pump bays. The major factors that can affect the selection of a concept and design development for a water intake are: a) The occurrence of dead water zones, flow separation or reverse flow b) Vortex building and air entrainment in the pump compartments c) Submerged vortices building in the pump compartments d) Low velocity area e) Strong rotational flow f) Strong cross flow appear in front of pump units g) Pre rotation in the pump suction lines. Dye injection was used to examine the stratified flow behavior along water. The existing design of the pump bays was found to produce a uniform, symmetrical flow distribution in the approach flow, weak but persistent floor and side-wall-attached submerged vortices, avoiding cross flow and reverse flow in front of the pumps and negligible swirling motion in the pump suction. Modified design includes (i) profiling low velocity area (ii) adding flow deflectors along inner walls (iii) infill area of low velocity (iv) adding suspended baffle in front of drum screens (v) adding diffuser block in front of pumps (vi) provision of floating booms in front of pumps.

Characteristics of air entrainment during dynamic wetting failure along a planar substrate

2014 ◽  
Vol 747 ◽  
pp. 119-140 ◽  
Author(s):  
E. Vandre ◽  
M. S. Carvalho ◽  
S. Kumar
Keyword(s):  
High Speed ◽  
Water Solution ◽  
Air Entrainment ◽  
Dynamic Contact ◽  
Operating Conditions ◽  
Dynamic Wetting ◽  
Glycerol Water ◽  
Planar Substrate ◽  
Wide Range ◽  
Stationary Plate

AbstractCharacteristic substrate speeds and meniscus shapes associated with the onset of air entrainment are studied during dynamic wetting failure along a planar substrate. Using high-speed video, the behaviour of the dynamic contact line (DCL) is recorded as a tape substrate is drawn through a bath of a glycerol/water solution. Air entrainment is identified by triangular air films that elongate from the DCL above some critical substrate speed. Meniscus confinement within a narrow gap between the substrate and a stationary plate is shown to delay air entrainment to higher speeds for a wide range of liquid viscosities, expanding upon the findings of Vandre, Carvalho & Kumar (J. Fluid Mech., vol. 707, 2012, pp. 496–520). A pressurized liquid reservoir controls the meniscus position within the confinement gap. It is found that liquid pressurization further postpones air entrainment when the meniscus is located near a sharp corner along the stationary plate. Meniscus shapes recorded near the DCL demonstrate that operating conditions influence the size of entrained air films, with smaller films appearing in the more viscous solutions. Regardless of size, air films become unstable to thickness perturbations and ultimately rupture, leading to the entrainment of air bubbles. Recorded critical speeds and air-film sizes compare well to predictions from a hydrodynamic model for dynamic wetting failure, suggesting that strong air stresses near the DCL trigger the onset of air entrainment.

Canal Wave Oscillations from Expansion of I-84 Bridge in Boise, Idaho

2012 ◽  
Vol 2309 (1) ◽  
pp. 200-205
Author(s):  
William Rahmeyer ◽  
J. M. Clegg ◽  
S. L. Barfuss
Keyword(s):  
New York ◽  
Physical Model ◽  
Unique Solution ◽  
Wave Phenomenon ◽  
Bridge Columns ◽  
Bridge Abutments ◽  
Wave Problem ◽  
Model Study ◽  
Bridge Crossing

Recent improvements and the widening of the I-84 Bridge crossing of the New York Canal in Boise, Idaho, have increased the number of bridge columns from 28 to 60. The resulting structure has two parallel rows of columns that extend across the width of the bridge longitudinally within the canal. After the widening of the bridge and addition of the bridge columns, the canal began experiencing an oscillating wave phenomenon that originated from the bridge columns and caused erosion of upstream and downstream canal banks and bridge abutments. A physical model study was conducted to investigate the wave phenomenon and determine what modifications to the columns or canal would be necessary to prevent the wave oscillations. The physical model was successful in simulating the wave phenomenon, and four different modifications for resolving the wave problem were tested in the model. A unique solution was found that used precast nose cones attached to selected columns. The nose cones have been installed in the prototype bridge crossing, and no wave oscillations have occurred since installation. This paper discusses the study to simulate the wave phenomenon and the four modifications that were evaluated to reduce or prevent wave oscillations.

Application of Reliability Analysis to Re-Qualification and Life Extension of Floating Production Unit Moorings

2016 ◽  
Author(s):  
J. Rosen ◽  
D. Johnstone ◽  
P. Sincock ◽  
A. E. Potts ◽  
D. Hourigan
Keyword(s):  
Reliability Analysis ◽  
Production Unit ◽  
Life Extension ◽  
Surface Model ◽  
Original Design ◽  
Coupled Models ◽  
Wide Range ◽  
Reliability Methods ◽  
Ocean Conditions ◽  
Failure Scenario

Life extension and asset integrity of Floating Production Unit (FPU) moorings are issues of increasing importance for operators due to changing production requirements, the requirement to extend service life, and circumstances where the met-ocean Basis of Design (BOD) has increased significantly over the life of the field. Reliability methods are gaining increasing acceptance as increased computing power allows large numbers of simulations to be undertaken using realistic fully coupled models that are validated against prior experiments. When applied to the re-qualification and life extension of FPU moorings, particularly with regard to re-qualification and life extension of in-place moorings, reliability analysis offers considerable advantages over conventional deterministic return period design. This paper details the application of a reliability approach to re-qualification and life extension of a turret-moored FPU that had design met-ocean conditions increased significantly over the life of the field. It explores key elements of reliability analysis including the probabilistic characterisation of met-ocean conditions, adequate representation of vessel dynamics and mooring loads in a Response Surface Model, and a selection of algorithms to solve for the system probability of failure. Discussion points include the advantages of the explicit identification of the most likely failure scenario versus uncertainty as to whether the worst design case has been identified, and the potential for rapid reassessment of reliability for specific design conditions (such as a degraded mooring system or a system for which degradation is ongoing). The results of this study demonstrate the significant advantages to the industry conferred by adopting reliability methods in the re-certification and life extension of existing FPU moorings. In particular, the study highlights that conventional mooring code deterministic design methods, whilst adequate for original design purposes, lack sufficient fidelity to address the multi-faceted issue of re-assessment of notionally marginal legacy systems. For a degraded existing mooring, an application of these methods can demonstrate that the level of reliability of the system is still acceptable, whereas a conventional approach may produce an over-conservative indication that the mooring is non-compliant. Applicable to a wide range of FPUs requiring re-qualification or life extension, the techniques discussed also provide pointers to more efficient and reliable mooring design for not just existing, but also for new FPUs.

scholarly journals Physical model study of beach profile evolution by sea level rise in the presence of seawalls

2018 ◽  
Vol 136 ◽  
pp. 172-182 ◽  
Author(s):  
T. Beuzen ◽  
I.L. Turner ◽  
C.E. Blenkinsopp ◽  
A. Atkinson ◽  
F. Flocard ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Physical Model ◽  
Sea Level ◽  
Beach Profile ◽  
Model Study

A physical model study of the storage of low-grade heat in unsaturated chalk

1982 ◽  
Vol 56 (1-2) ◽  
pp. 61-83 ◽  
Author(s):  
John B.W. Day ◽  
J.H. Black ◽  
N.A. Chapman ◽  
D.H. Hall
Keyword(s):  
Physical Model ◽  
Low Grade ◽  
Model Study ◽  
Low Grade Heat

scholarly journals A comparative survey of the impacts of extreme rainfall in two international case studies

2017 ◽  
Author(s):  
Matthieu Spekkers ◽  
Viktor Rözer ◽  
Annegret Thieken ◽  
Marie-Claire ten Veldhuis ◽  
Heidi Kreibich
Keyword(s):  
Case Studies ◽  
Online Survey ◽  
Residential Buildings ◽  
Age Groups ◽  
Extreme Rainfall ◽  
Water Levels ◽  
Economic Losses ◽  
Biased Sampling ◽  
Wide Range ◽  
Damage Data

Abstract. Flooding is assessed as the most important natural hazard in Europe, causing thousands of deaths, affecting millions of people and accounting for large economic losses in the past decade. Little is known about the damage processes associated with extreme rainfall in cities, due to a lack of accurate, comparable and consistent damage data. The objective of this study is to investigate the impacts of extreme rainfall on residential buildings and how affected households coped with these impacts in terms of precautionary and emergency actions. Analyses are based on a unique dataset of damage characteristics and a wide range of potential damage explaining variables at the household level, collected through computer-aided telephone interviews (CATI) and an online survey. Exploratory data analyses based on a total of 859 completed questionnaires in the cities of Münster (Germany) and Amsterdam (the Netherlands) revealed that the uptake of emergency measures is related to characteristics of the hazardous event. In case of high water levels, more efforts are made to reduce damage, while emergency response that aims to prevent damage is less likely to be effective. The difference in magnitude of the events in Münster and Amsterdam in terms of rainfall intensity and water depth, is probably also the most important cause for the differences between the cities in terms of the suffered financial losses. Factors that significantly contributed to damage in at least one of the case studies are water contamination, the presence of a basement in the building and people's awareness of the upcoming event. Moreover, this study confirms conclusions by previous studies that people's experience with damaging events positively correlates with precautionary behaviour. For improving future damage data acquisition, we recommend to include cell-phones in a CATI survey to avoid biased sampling towards certain age groups.

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