scholarly journals A Numerical Investigation into the PAT Hydrodynamic Response to Impeller Rotational Speed Variation

2021 ◽  
Vol 13 (14) ◽  
pp. 7998
Author(s):  
Maxime Binama ◽  
Kan Kan ◽  
Hui-Xiang Chen ◽  
Yuan Zheng ◽  
Daqing Zhou ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Distribution Systems ◽  
Water Distribution ◽  
Production Efficiency ◽  
Operating Conditions ◽  
Energy Regulation ◽  
Speed Increase ◽  
Energy Field ◽  
Long Run ◽  
Study Results

The utilization of pump as turbines (PATs) within water distribution systems for energy regulation and hydroelectricity generation purposes has increasingly attracted the energy field players’ attention. However, its power production efficiency still faces difficulties due to PAT’s lack of flow control ability in such dynamic systems. This has eventually led to the introduction of the so-called “variable operating strategy” or VOS, where the impeller rotational speed may be controlled to satisfy the system-required flow conditions. Taking from these grounds, this study numerically investigates PAT eventual flow structures formation mechanism, especially when subjected to varying impeller rotational speed. CFD-backed numerical simulations were conducted on PAT flow under four operating conditions (1.00 QBEP, 0.82 QBEP, 0.74 QBEP, and 0.55 QBEP), considering five impeller rotational speeds (110 rpm, 130 rpm, 150 rpm, 170 rpm, and 190 rpm). Study results have shown that both PAT’s flow and pressure fields deteriorate with the machine influx decrease, where the impeller rotational speed increase is found to alleviate PAT pressure pulsation levels under high-flow operating conditions, while it worsens them under part-load conditions. This study’s results add value to a thorough understanding of PAT flow dynamics, which, in a long run, contributes to the solution of the so-far existent technical issues.

scholarly journals Modeling Bacterial Regrowth and Trihalomethane Formation in Water Distribution Systems

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 463
Author(s):  
Gopinathan R. Abhijith ◽  
Leonid Kadinski ◽  
Avi Ostfeld
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Mechanistic Model ◽  
Water Distribution Systems ◽  
Sensitivity Study ◽  
Operating Conditions ◽  
Growth Rate Constant ◽  
Model Parameters ◽  
Bacterial Regrowth ◽  
The Impact

The formation of bacterial regrowth and disinfection by-products is ubiquitous in chlorinated water distribution systems (WDSs) operated with organic loads. A generic, easy-to-use mechanistic model describing the fundamental processes governing the interrelationship between chlorine, total organic carbon (TOC), and bacteria to analyze the spatiotemporal water quality variations in WDSs was developed using EPANET-MSX. The representation of multispecies reactions was simplified to minimize the interdependent model parameters. The physicochemical/biological processes that cannot be experimentally determined were neglected. The effects of source water characteristics and water residence time on controlling bacterial regrowth and Trihalomethane (THM) formation in two well-tested systems under chlorinated and non-chlorinated conditions were analyzed by applying the model. The results established that a 100% increase in the free chlorine concentration and a 50% reduction in the TOC at the source effectuated a 5.87 log scale decrement in the bacteriological activity at the expense of a 60% increase in THM formation. The sensitivity study showed the impact of the operating conditions and the network characteristics in determining parameter sensitivities to model outputs. The maximum specific growth rate constant for bulk phase bacteria was found to be the most sensitive parameter to the predicted bacterial regrowth.

Contrarotating Open Rotor Operation for Improved Aerodynamics and Noise at Takeoff

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Alexios Zachariadis ◽  
Cesare Hall ◽  
Anthony B. Parry
Keyword(s):  
Rotational Speed ◽  
Carbon Dioxide Emissions ◽  
Three Dimensional ◽  
Separated Flow ◽  
Operating Conditions ◽  
Aviation Fuel ◽  
Lower Velocity ◽  
Speed Increase ◽  
Community Noise ◽  
Open Rotor

The contrarotating open rotor is, once again, being considered as an alternative to the advanced turbofan to address the growing pressure to cut aviation fuel consumption and carbon dioxide emissions. One of the key challenges is meeting community noise targets at takeoff. Previous open rotor designs are subject to poor efficiency at takeoff due to the presence of large regions of separated flow on the blades as a result of the high incidence needed to achieve the required thrust. This is a consequence of the fixed rotor rotational speed constraint typical of variable pitch propellers. Within the study described in this paper, an improved operation is proposed to improve performance and reduce rotor-rotor interaction noise at takeoff. Three-dimensional computational fluid dynamics (CFD) calculations have been performed on an open rotor rig at a range of takeoff operating conditions. These have been complemented by analytical tone noise predictions to quantify the noise benefits of the approach. The results presented show that for a given thrust, a combination of reduced rotor pitch and increased rotor rotational speed can be used to reduce the incidence onto the front rotor blades. This is shown to eliminate regions of flow separation, reduce the front rotor tip loss and reduce the downstream stream tube contraction. The wakes from the front rotor are also made wider with lower velocity defect, which is found to lead to reduced interaction tone noise. Unfortunately, the necessary increase in blade speed leads to higher relative Mach numbers, which can increase rotor alone noise. In summary, the combined CFD and aeroacoustic analysis in this paper shows how careful operation of an open rotor at takeoff, with moderate levels of repitch and speed increase, can lead to improved front rotor efficiency as well as appreciably lower overall noise across all directivities.

scholarly journals Pressure-driven modelling of water distribution systems

2003 ◽  
Vol 3 (1-2) ◽  
pp. 255-261 ◽  
Author(s):  
T. Tanyimboh ◽  
B. Tahar ◽  
A. Templeman
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Line Search ◽  
Water Distribution Systems ◽  
Operating Conditions ◽  
Governing Equations ◽  
Novel Method ◽  
Newton Raphson ◽  
Abnormal Operating Conditions ◽  
Demand Driven Analysis

This paper presents a novel method to model water distribution systems (WDS) with insufficient pressure. Methods for the prediction of the performance of a WDS with pressure deficiencies are reviewed. The influence of imposed relationships between nodal heads and outflows is assessed and numerical results are given. A Newton-Raphson technique plus line search is employed for solving the governing equations. It is demonstrated that the approach offers superior results for the hydraulic performance of networks under abnormal operating conditions compared to demand-driven analysis-based models.

A New Energy Optimization Strategy for Pumping Operation in Water Distribution Systems

2012 ◽  
Author(s):  
Dhafar Al-Ani ◽  
Saeid Habibi
Keyword(s):  
Distribution System ◽  
Energy Cost ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water Distribution Systems ◽  
Energy Optimization ◽  
Operating Conditions ◽  
Optimization Strategy ◽  
Multi Objective

As time goes on, more and more operating-modes based on changing demand profiles will be compiled to enrich the range of feasible solutions for a water distribution system. This implies the conservation of energy consumed by a water pumping station and improves the ability for energy optimization. Another important goal was improving safety, reliability, and maintenance cost. In this paper, three important goals were addressed: cost-effectives, safety, and self-sustainability operations of water distribution systems. In this work, the objective functions to optimize were total electrical energy cost, maintenance costs, and reservoir water level variation while preserving the service provided to water clients. To accomplish these goals, an effective Energy Optimization Strategy (EOS) that manages trade-off among operational cost, system safety, and reliability was proposed. Moreover, the EOS aims at improving the operating conditions (i.e., pumping schedule) of an existing network system (i.e., with given capacities of tanks) and without physical changes in the infrastructure of the distribution systems. The new strategy consisted of a new Parallel Multi-objective Particle Swarm optimization with Adaptive Search-space Boundaries (P-MOPSO-ASB) and a modified EPANET. This has several advantages: obtaining a Pareto-front with solutions that are quantitatively equally good and providing the decision maker with the opportunity to qualitatively compare the solutions before their implementation into practice. The multi-objective optimization approach developed in this paper follows modern applications that combine an optimization algorithm with a network simulation model by using full hydraulic simulations and distributed demand models. The proposed EOS was successfully applied to a rural water distribution system, namely Saskatoon West. The results showed that a potential for considerable cost reductions in total energy cost was achieved (approximately % 7.5). Furthermore, the safety and the reliability of the system are preserved by using the new optimal pump schedules.

scholarly journals Formulation of Nao Equation According to Nao Framework

2021 ◽  
Vol 12 (3) ◽  
pp. 5042-5050
Author(s):  
A. H. Abdul Rasib Et. al.
Keyword(s):  
Manufacturing Industry ◽  
Production Efficiency ◽  
Value Added ◽  
Cost Effective ◽  
Lead Times ◽  
Critical Factors ◽  
Increase Production Efficiency ◽  
Post Process ◽  
Long Run ◽  
Study Results

Companies in manufacturing often find strategies to increase production efficiency and quality to be competitive in the long run. These strategies make companies remain profitable in a highly competitive market. Nonetheless, attempting to maintain a shorter production lead time is also vital as efficiency becomes a competitive priority. Whenever there are longer lead times, overtime is taken into account to meet the target. Overtime can be the most cost-effective way for companies to achieve their quality needs. Nevertheless, if poorly managed, overtime could quickly outstrip financial gains. This study aimed to establish the manufacturing industry model of non-value-added overtime (NAO) and formulate NAO equations. In this regard, the NAO equations were acquired from the critical factors of NAO. The vital aspects of NAO were then presented through the activities flow in the input/output manufacturing concept. The study results indicated that the highest critical factors contributed to the three processes: pre-process, in-process, and post-process.

scholarly journals Enhanced Water Age Performance Assessment in Distribution Networks

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2574
Author(s):  
Laura Monteiro ◽  
Ricardo Algarvio ◽  
Dídia Covas
Keyword(s):  
Water Quality ◽  
Performance Assessment ◽  
Reference Values ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Operating Conditions ◽  
Water Age ◽  
Major Improvement ◽  
Age Limits

Water age is frequently used as a surrogate for water quality in distribution networks and is often included in modelling and optimisation studies, though there are no reference values or standard performance functions for assessing the network behaviour regarding water age. This paper presents a novel methodology for obtaining enhanced system-specific water age performance assessment functions, tailored for each distribution network. The methodology is based on the establishment of relationships between the chlorine concentration at the sampling nodes and simulated water age. The proposed methodology is demonstrated through application to two water distribution systems in winter and summer seasons. Obtained results show a major improvement in comparison with those obtained by published performance functions, since the water age limits of the performance functions used herein are tailored to the analysed networks. This demonstrates that the development of network-specific water age performance functions is a powerful tool for more robustly and reliably defining water age goals and evaluating the system behaviour under different operating conditions.

scholarly journals Analysis of the effect of pressure control on leakages in distribution systems by FAVAD equation and field applications

2021 ◽  
Author(s):  
Özgür Özdemir ◽  
Mahmut Fırat ◽  
Salih Yılmaz ◽  
Mustafa Usluer
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Field Tests ◽  
Pressure Control ◽  
Operating Conditions ◽  
Water Losses ◽  
Effect Of Pressure ◽  
Minimum Night Flow ◽  
Pressure Control System ◽  
Daily Water

Abstract Pressure has an important effect on the occurrence of failures/leaks in water distribution systems (WDSs) or the change of leakage in existing leakages. For this reason, monitoring the pressure is important especially for analyzing the changes in the day and night, determining the fluctuations and applying pressure management (PM) to ensure normal operating conditions. In this study, the effect of pressure on water losses and minimum night flow (MNF) was carried out according to the Fixed and Varied Area Discharge (FAVAD) approach which allows the amount of leakage to be calculated based on the change in pressure and field tests. The minimum flow rate and potential leakage were determined under the network operating conditions before the pressure control in region. Then, considering the features of the region, pressure was reduced with the pressure control system and MNFs and leaks were monitored. By reducing the pressure from 9.10 bar to 3.2 bar in the region, the MNF rate was reduced from 6.95 l/s to 3.29 l/s. The daily water savings in the system inlet volume is 78.44 m3/day and the annual saving is 28,624 m3 /year. The results obtained are very important for practitioners in terms of implementing PM in the field.

scholarly journals Intelligent system for control of water distribution networks

2017 ◽  
Vol 18 (4) ◽  
pp. 1270-1281 ◽  
Author(s):  
Emânuel Guerra Barros Filho ◽  
Laís Régis Salvino ◽  
Saulo de Tarso Marques Bezerra ◽  
Moisés Menezes Salvino ◽  
Heber Pimentel Gomes
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Research Study ◽  
Intelligent System ◽  
Rotation Speed ◽  
Electricity Consumption ◽  
Distribution Networks ◽  
Maximum Error ◽  
Operating Conditions ◽  
Water Distribution Networks

Abstract The objective of this research study was the development of an intelligent system based on artificial neural networks for water distribution networks that operate with parallel pumps. The purpose of the system is to automate the process and to define the operating state of the electric motors (on, off or with partial rotation speed). The intelligent system developed is generic, which allows the application of its control structure in similar processes, and it was applied in an experimental setup that simulates a real water supply system. The performance of the network was tested experimentally under different operating conditions, including in the presence of disturbances. The settling time was, in all experiments, less than 30 seconds, the tests did not show overshoot and the maximum error was 2.9%. Results showed excellent performance in terms of pressure regulation, and it is hoped that the controller can be successfully implemented in real water distribution systems, in order to reduce water and electricity consumption, decrease maintenance costs and increase the reliability of operating procedures.

scholarly journals Multi-stage parameter-constraining inverse transient analysis for pipeline condition assessment

2018 ◽  
Vol 20 (2) ◽  
pp. 281-300 ◽  
Author(s):  
Chi Zhang ◽  
Aaron C. Zecchin ◽  
Martin F. Lambert ◽  
Jinzhe Gong ◽  
Angus R. Simpson
Keyword(s):  
Transient Analysis ◽  
Distribution Systems ◽  
Water Distribution ◽  
Search Space ◽  
Condition Assessment ◽  
Estimation Accuracy ◽  
Model Parameters ◽  
Multi Stage ◽  
Study Results ◽  
Transmission Pipelines

Abstract Fault detection in water distribution systems is of critical importance for water authorities to maintain pipeline assets effectively. This paper develops an improved inverse transient analysis (ITA) method for the condition assessment of water transmission pipelines. For long transmission pipelines ITA approaches involve models using hundreds of discretized pipe reaches (therefore hundreds of model parameters). As such, these methods struggle to accurately and uniquely determine the many parameter values, despite achieving a very good fit between the model predictions and measured pressure responses. In order to improve the parameter estimation accuracy of ITA applied to these high dimensional problems, a multi-stage parameter-constraining ITA approach for pipeline condition assessment is proposed. The proposed algorithm involves the staged constraining of the parameter search-space to focus the inverse analysis on pipeline sections that have a higher likelihood of being in an anomalous state. The proposed method is verified by numerical simulations, where the results confirm that the parameters estimated by the proposed method are more accurate than the conventional ITA. The proposed method is also verified by a field case study. Results show that anomalies detected by the proposed methods are generally consistent with anomalies detected by ultrasonic measurement of pipe wall thickness.

scholarly journals An Advanced Learning-Based Multiple Model Control Supervisor for Pumping Stations in a Smart Water Distribution System

Mathematics ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 887 ◽  
Author(s):  
Alexandru Predescu ◽  
Ciprian-Octavian Truică ◽  
Elena-Simona Apostol ◽  
Mariana Mocanu ◽  
Ciprian Lupu
Keyword(s):  
Machine Learning ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Metropolitan Areas ◽  
Operating Conditions ◽  
Multiple Model ◽  
Smart Water ◽  
Model Control

Water distribution is fundamental to modern society, and there are many associated challenges in the context of large metropolitan areas. A multi-domain approach is required for designing modern solutions for the existing infrastructure, including control and monitoring systems, data science and Machine Learning. Considering the large scale water distribution networks in metropolitan areas, machine and deep learning algorithms can provide improved adaptability for control applications. This paper presents a monitoring and control machine learning-based architecture for a smart water distribution system. Automated test scenarios and learning methods are proposed and designed to predict the network configuration for a modern implementation of a multiple model control supervisor with increased adaptability to changing operating conditions. The high-level processing and components for smart water distribution systems are supported by the smart meters, providing real-time data, push-based and decoupled software architectures and reactive programming.

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