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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Algorithms for the solution of flow networks containing open channels

Ho, Fan-Young (Newton) January 1994 (has links)
Hydraulic networks involving free surface open channel flows have many applications, such as water and wastewater treatment plants, irrigation and drainage systems. In such systems, networks of open channels are interlinked with hydraulic control structures in a complex fashion, and determination of the resulting flow distribution and head-losses in such systems is far more complicated and time consuming than the analogous problem of pipe networks. This is because the relationship between flow and head-loss for free surface flow systems also depends upon the water levels and controls operating within the network. The objective of the research is to develop a model which enables the flow distribution throughout such networks to be determined.
2

Otimização de operação de rede por um modelo híbrido (hidrodinâmico-genético). / Optimization of hydraulic networks through a hybrid model (hydrodynamic - genetic).

Diniz, Victor Emanuel Mello de Guimarães 23 April 2004 (has links)
Este trabalho apresenta um modelo híbrido, que após calcular as cargas e as vazões para o regime permanente e para o regime extensivo, utiliza um algoritmo genético para otimizar o controle operacional de redes hidráulicas. Para se calcular os regimes permanente e extensivo utilizou-se o Método Matricial. O Algoritmo Genético utilizou números binários. A função objetivo minimiza a soma das potências hidráulicas dissipadas na rede como um todo de todos os períodos de cálculo do regime extensivo. A parte do modelo híbrido que se refere ao cálculo hidráulico está funcionando a contento, pois os valores obtidos pelo modelo para as duas redes utilizadas como exemplo neste projeto estão próximos dos valores originais obtidos da literatura pesquisada. A parte do modelo híbrido que se refere ao algoritmo genético está funcionando a contento, pois os valores da função objetivo obtidos pelo modelo convergiram em todos os cálculos nos quais o elitismo foi utilizado. A otimização proposta neste trabalho serve para ser utilizada em redes de abastecimento que apresentem problemas operacionais e que precisem ser resolvidos com a instalação de válvulas ou que tenham válvulas instaladas. / This report presents a hybrid model that calculates the heads and flows of a hydraulic network system and then uses a genetic algorithm to optimize the operational control of the hydraulic network. To calculate the steady flow and the extensive period it was used the Matrix Method. The GA used binary numbers. The objective function minimizes the sum of the dissipated hydraulic power in the whole network of all calculated periods during the day. The hybrid model part that refers to the hydraulic calculation is working well, because the values calculated by the model applied to the networks used as examples are similar to the ones obtained from the technical literature. The hybrid model part that refers to the GA is working well, because the objective function values calculated by the model converged whenever the elitism was used. The proposed optimization of this work is to be used in hydraulic networks that present operational problems that need to be solved either installing valves or having installed valves.
3

Otimização de operação de rede por um modelo híbrido (hidrodinâmico-genético). / Optimization of hydraulic networks through a hybrid model (hydrodynamic - genetic).

Victor Emanuel Mello de Guimarães Diniz 23 April 2004 (has links)
Este trabalho apresenta um modelo híbrido, que após calcular as cargas e as vazões para o regime permanente e para o regime extensivo, utiliza um algoritmo genético para otimizar o controle operacional de redes hidráulicas. Para se calcular os regimes permanente e extensivo utilizou-se o Método Matricial. O Algoritmo Genético utilizou números binários. A função objetivo minimiza a soma das potências hidráulicas dissipadas na rede como um todo de todos os períodos de cálculo do regime extensivo. A parte do modelo híbrido que se refere ao cálculo hidráulico está funcionando a contento, pois os valores obtidos pelo modelo para as duas redes utilizadas como exemplo neste projeto estão próximos dos valores originais obtidos da literatura pesquisada. A parte do modelo híbrido que se refere ao algoritmo genético está funcionando a contento, pois os valores da função objetivo obtidos pelo modelo convergiram em todos os cálculos nos quais o elitismo foi utilizado. A otimização proposta neste trabalho serve para ser utilizada em redes de abastecimento que apresentem problemas operacionais e que precisem ser resolvidos com a instalação de válvulas ou que tenham válvulas instaladas. / This report presents a hybrid model that calculates the heads and flows of a hydraulic network system and then uses a genetic algorithm to optimize the operational control of the hydraulic network. To calculate the steady flow and the extensive period it was used the Matrix Method. The GA used binary numbers. The objective function minimizes the sum of the dissipated hydraulic power in the whole network of all calculated periods during the day. The hybrid model part that refers to the hydraulic calculation is working well, because the values calculated by the model applied to the networks used as examples are similar to the ones obtained from the technical literature. The hybrid model part that refers to the GA is working well, because the objective function values calculated by the model converged whenever the elitism was used. The proposed optimization of this work is to be used in hydraulic networks that present operational problems that need to be solved either installing valves or having installed valves.
4

Desarrollo e implementación de algoritmos para la optimización energética en tiempo real de redes hidráulicas a presión

Alonso Campos, Joan Carles 20 January 2022 (has links)
[ES] El objetivo general de la presente Tesis es investigar metodologías que permitan obtener en tiempo real los parámetros de operación de redes hidráulicas a presión que minimicen el consumo y/o el coste energético, garantizando el cumplimiento de las condiciones de funcionamiento necesarias para una adecuada calidad del servicio. Al tratarse del ámbito de la operación diaria de la red, una de las condiciones indispensables que deben reunir los métodos de optimización es una respuesta lo suficientemente rápida como para que no solo se pueda disponer de las soluciones más convenientes en el momento de ejecutar las consignas de operación, sino que además se habilite un procedimiento flexible que permita dar respuesta a posibles cambios en las predicciones o eventos que puedan producirse. Se ha abordado de manera aislada la optimización energética de los subsistemas de transporte de agua y la de los subsistemas de distribución debido a las distintas características que se pueden observar en ellos. En la parte relativa a los subsistemas de distribución, particularizada al caso de un sistema de riego con bombeo directo a red, se han explorado los métodos metaheurísticos de optimización, realizando varias aportaciones originales orientadas a la mejora en la eficiencia computacional de los mismos, debido a la necesidad de obtener una respuesta rápida compatible con la toma de decisiones en tiempo real. En cuanto a los subsistemas de transporte, se ha explorado la aplicabilidad del método determinista de optimización por programación lineal, a la vista de las importantes ventajas que presenta respecto al resto de métodos generales de optimización. Asimismo, en el contexto de los subsistemas de transporte, se ha trabajado en la definición de una heurística basada en el cálculo del coste energético y/o económico del agua entregada en los puntos de consumo y almacenada en los depósitos intermedios, que ha permitido formular un algoritmo voraz para la optimización energética en cada instante de tiempo. Este método ha conseguido igualar el desempeño alcanzado mediante la programación lineal y se espera que ofrezca unas mejores capacidades en sistemas con un comportamiento marcadamente no lineal, así como también una mejor adaptación a problemas de optimización con la participación de energías renovables. / [CA] L'objectiu general de la present Tesi és la investigació de metodologies que permeten obtindre en temps real els paràmetres d'operació de xarxes hidràuliques a pressió que minimitzen el consum i/o el cost energètic, garantint el compliment de les condicions de funcionament necessàries per a una adequada qualitat del servei. En tractar-se de l'àmbit de l'operació diària de la xarxa, una de les condicions indispensables que han de reunir els mètodes d'optimització és una resposta prou ràpida com perquè no sols es puga disposar de les solucions més convenients en el moment d'executar les consignes d'operació, sinó que a més s'habilite un procediment flexible que permeta donar resposta a possibles canvis en les prediccions o esdeveniments que puguen produir-se. S'ha abordat de manera aïllada l'optimització energètica dels subsistemes de transport d'aigua i la dels subsistemes de distribució (reg per injecció directa) a causa de les diferents característiques que es poden observar en ells. En el treball amb els subsistemes de distribució s'han explorat les possibilitats que ofereixen els mètodes meta-heurístics d'optimització, realitzant diverses aportacions originals orientades a la millora en l'eficiència computacional dels mateixos a causa de la necessitat d'obtindre una resposta més ràpida que siga compatible amb la presa de decisions en temps real. Quant als subsistemes de transport, s'ha explorat l'aplicabilitat del mètode determinista d'optimització per programació lineal a la vista dels importants avantatges que presenta respecte a la resta de mètodes generals d'optimització. Així mateix, en el context dels subsistemes de transport, s'ha treballat en la definició d'una bona heurística basada en el càlcul del cost energètic i/o econòmic de l'aigua entregada en els punts de consum i en els dipòsits intermedis, que ha permés formular un mètode voraç per a l'optimització energètica en cada instant de temps. Aquest mètode ha aconseguit igualar l'acompliment aconseguit mitjançant la programació lineal i s'espera que oferisca unes millors capacitats en sistemes amb un comportament més marcadament no lineal, així com també una millor adaptació a problemes d'optimització amb participació d'energies renovables. / [EN] The general objective of this Thesis is the research of methodologies to obtain in real time the operating parameters of pressurized hydraulic networks that minimize energy consumption and/or cost, ensuring compliance with the operating conditions necessary for an appropriate quality of service. Since this is the field of daily network operation, one of the indispensable conditions that optimization methods must meet is a response fast enough so that not only the most convenient solutions are available at the time of executing the operating instructions, but also a flexible procedure is provided to allow a response to possible changes in the predictions or events that may occur. The energy optimization of the water transport subsystems and that of the distribution subsystems (direct injection irrigation) have been approached separately due to the different characteristics that can be observed in them. In the work with distribution subsystems, the possibilities offered by metaheuristic optimization methods have been explored, making several original contributions aimed at improving their computational efficiency due to the need to obtain a faster response that is compatible with real-time decision making. Regarding transport subsystems, the applicability of the deterministic method of optimization by linear programming has been explored in view of the important advantages it presents with respect to the rest of the general optimization methods. Also, in the context of transport subsystems, there has been a work on the definition of a good heuristic based on the calculation of the energy and/or economic cost of the water delivered at the consumption points and intermediate reservoirs, which has allowed to formulate a greedy method for energy optimization at each time instant. This method has been able to match the performance achieved by linear programming and is expected to offer better capabilities in systems with a more marked non-linear behaviour, as well as a better adaptation to optimization problems involving renewable energies. / Alonso Campos, JC. (2021). Desarrollo e implementación de algoritmos para la optimización energética en tiempo real de redes hidráulicas a presión [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/180389 / TESIS
5

Modèles et observateurs pour les systèmes d'écoulement sous pression. Extension aux systèmes chaotiques / Tools of control and monitoring for networks of water distribution at free surface and under pressure

Torres Ortiz, Flor Lizeth 28 January 2011 (has links)
Principalement, ce travail présente l’application d’observateurs non linéairespour la détection de fuites (uniques, séquentielles et simultanées) dans des canalisationssous pression. Les observateurs présentés ici ont été conçus à partir d’uneversion discrète des équations du coup de bélier, qui a été obtenue en utilisant laméthode des différences finies et en prenant comme alternative la méthode de collocationorthogonale. Les modèles discrets ainsi que certains observateurs ont étévalidés par une série d’expériences effectuées dans des canalisations d’essai. D’autrepart, une nouvelle version d’observateurs à grand gain pour des systèmes non uniformémentobservables a été développée. Elle a été utilisée pour la détection de fuitesainsi que pour la synchronisation de systèmes chaotiques avec des paramètres inconnus.Des résultats de convergence, expérimentaux et en simulation sont exposésdans ce mémoire. / This work mainly deals with the application of nonlinear observers for the detectionof leaks (single, sequential and simultaneous) in pipes under pressure. Theproposed observers were conceived from a spatially discretized version of the waterhammer equations. This version was obtained using the finite difference method ,as an alternative to the orthogonal collocation method also considered. The discretemodels, as well as some observers were validated by a set of experiments realizedin test pipes. This work also gave rise to a new version of high gain observers fornon-uniformly observable systems. Firstly used for the purpose of leak detection,it was successfully applied to the synchronization of chaotic systems with unknownparameters as well. Its presentation includes a formal convergence proof, as well assimulation and experimental results. / Este trabajo trata principalmente la aplicación de observadores no lineales parala detección de fugas (únicas, secuenciales y simultaneas) en tuberías bajo presión.Los observadores que aquí se presentan fueron concebidos a partir de una versióndiscreta (espacialmente) de las ecuaciones del golpe de ariete. Tal versión se logróutilizando el método de diferencias finitas, y como alternativa el método decolocación ortogonal. Los modelos discretos, así como ciertos observadores, fueronvalidados mediante una serie de experimentos realizados en tuberías de ensayo.Este trabajo también dio origen a una nueva versión de observadores de granganancia para sistemas no uniformemente observables, la cual se utilizó para ladetección de fugas, así como para la sincronización de sistemas caóticos con parámetrosdesconocidos. Su presentación incluye resultados de convergencia formales,en simulación, y experimentales.
6

Estudo da conveniÃncia da identificaÃÃo do fator de atrito e da rugosidade em redes de distribuiÃÃo de Ãgua atravÃs do mÃtodo transiente inverso com algoritmo genÃtico / Study of the friction factor identification of convenience and roughness in water distribution networks through the reverse transient method with genetic algorithm

Gabriela Celso Melo Pinheiro de Vasconcelos 10 November 2014 (has links)
A Ãgua à um recurso natural essencial para todas as formas de vida e a sua distribuiÃÃo deve ser realizada com qualidade e sem desperdÃcios. Um dos mÃtodos de otimizaÃÃo dos sistemas de distribuiÃÃo de Ãgua à baseado na simulaÃÃo (modelagem) de redes hidrÃulicas reais atravÃs de modelos computacionais capazes de prever o seu comportamento nas situaÃÃes diversas ao logo da sua vida Ãtil. As principais etapas desse mÃtodo sÃo calibraÃÃo; operaÃÃo e controle; projeto e otimizaÃÃo; e traÃado de redes. A ideia deste trabalho à aprimorar uma dessas tÃcnicas, a de calibraÃÃo, processo de identificaÃÃo dos parÃmetros das tubulaÃÃes (fator de atrito, rugosidade, diÃmetros e outros) em redes existentes, na qual os mesmos sÃo considerados desconhecidos. A metodologia adotada à o MÃtodo Transiente Inverso (MTI) com otimizaÃÃo da tÃcnica de seleÃÃo da soluÃÃo atravÃs do algoritmo GenÃtico (AG). O objetivo principal à calibrar os principais parÃmetros (fator de atrito e rugosidade) a fim de analisar a conveniÃncia de duas tÃcnicas: cÃlculo do fator de atrito pelo mÃtodo pelo MTI-AG e a partir da rugosidade (com uso da fÃrmula de Swamee, 1993). O estudo à realizado para duas redes sintÃticas tiradas da literatura, mas que representam sistemas reais. As condiÃÃes impostas para a anÃlise sÃo: duas manobras de vÃlvulas (lenta e brusca) responsÃveis pelo evento transiente, o monitoramento de cargas transientes em somente 20% dos nÃs das redes e a utilizaÃÃo de dois tipo de seleÃÃo de soluÃÃo do algoritmo genÃtico (com elitismo e sem elitismo). Os experimentos sÃo realizados a partir de trÃs programas: o primeiro calcula as condiÃÃes permanentes, o segundo fornece cargas transientes por meio do MÃtodo das CaracterÃsticas (MOC) na busca das soluÃÃes das equaÃÃes de movimento no escoamento transiente e o terceiro, que trabalha de forma conjugada com os demais, seleciona os melhores resultados atravÃs de iteraÃÃes realizadas conforme o algoritmo genÃtico, tÃcnica inspirada nos mecanismos de evoluÃÃo dos seres vivos. Os resultados encontrados indicam que independente das condiÃÃes impostas inicialmente à mais eficiente identificar o fator de atrito a partir das rugosidades absolutas do que calibrar esse fator pelo MTI-AG devido a grande variabilidade dos fatores de atrito durante a ocorrÃncia do evento transiente. / Water is an essential natural resource for all life forms and their distribution should be carried out with quality and without waste. One of the methods of optimization of water distribution systems is based on the simulation (modeling) of real hydraulic networks using computational models that can predict their behavior in various situations the logo of its useful life. The main steps of this method are calibration; operation and control; design and optimization; and route networks. The idea of ​​this work is to improve one such technique, the calibration parameters of the pipes identification process (friction factor, surface roughness, diameter and the like) existing in networks in which they are considered unknown. The methodology adopted is the Transient Inverse Method (MTI) with optimization of the solution selection technique by Genetic Algorithm (GA). The main objective is to calibrate the main parameters (friction and roughness factor) to analyze the convenience of two techniques: calculation of the friction factor by the method by MTI-AG and from the roughness (using the formula Swamee, 1993 ). The study is carried out for two taken synthetic networks of literature, but represent real systems. The conditions for the analysis are: two maneuvers valves (slow and abrupt) responsible for the transient event, the monitoring of transient loads in only 20% of the nodes of the networks and the use of two types of solution selection of genetic algorithm (with elitism and without elitism). The experiments are carried out through three programs: the first calculates the permanent conditions, the second provides transient loads through the method of characteristics (MOC) in the search for solutions of the equations of motion in the transient flow and the third, who works so combined with others, selects the best results through iterations performed according to the genetic algorithm, a technique inspired by the mechanisms of evolution of living beings. The results indicate that regardless of the conditions imposed is initially more efficiently identify the friction factor from the absolute roughness than calibrate this factor by MTI-AG due to the great variability of friction factors for the occurrence of the transient event.
7

Metodologia eficiente para análise de redes complexas de abastecimento de água / Efficient method for analysis of complex networks of water supply

Aranda Saldaña, Edwin Antonio, 1974- 25 August 2018 (has links)
Orientador: Paulo Vatavuk / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-25T09:08:31Z (GMT). No. of bitstreams: 1 ArandaSaldana_EdwinAntonio_D.pdf: 3905557 bytes, checksum: d00eb707af3e32709401a2fbbcc42709 (MD5) Previous issue date: 2014 / Resumo: Este trabalho apresenta o desenvolvimento de um modelo computacional, baseado no Método da Teoria Linear Modificado (MTLM) proposto por WOOD (1981) e a implementação do algoritmo do Gradiente proposto por TODINI e PILATI (1988). Além disso, apresentam-se comparações entre ambos para a análise de redes de abastecimento de água de grande porte. De acordo com a proposta deste trabalho, para criar um modelo baseado no MTLM tornou-se indispensável a definição prévia de um algoritmo para a seleção automática de circuitos. Para essa finalidade, adotou-se o algoritmo de Breadth First Search (BFS), baseado na teoria dos grafos e utilizado satisfatoriamente na seleção automática dos circuitos nas redes hidráulicas. A formulação adotada na implementação dos modelos estabelece as equações de continuidade nos nós e as equações de conservação de carga nas malhas em termos da vazão para cada elemento do sistema, apresentando um conjunto de equações não lineares que relacionam vazão com perda de carga. Uma vez linearizado o sistema de equações, o uso da biblioteca numérica de programação e otimização (KLU) na resolução de sistemas lineares mostrou-se eficiente para ambos os métodos analisados neste trabalho. A validade e a consistência dos resultados fornecidos pelo modelo proposto foram confirmadas através de sua comparação com o software Epanet 2.0. Os resultados obtidos através de simulações com a finalidade de comparar os resultados obtidos pelo MTLM e pelo método que utiliza o algoritmo do gradiente mostraram a eficiência de processamento e do tempo computacional de ambos os métodos. As comparações foram feitas utilizando redes de até 1000 tubos, fornecendo resultados inéditos, pois os trabalhos encontrados, conforme a revisão bibliográfica, utilizaram redes pequenas com número de tubos em torno de 10% do tamanho das redes estudadas neste trabalho / Abstract: This thesis presents for the first time the development of two computational models, one model is based on the Modified linear theory method (MTLM) that was initially proposed by WOOD in 1981 and the other model is based on the implementation of the Gradient algorithm that was early proposed by TODINI and PILATI in 1987. In addition, this thesis presents comparisons between both methods for the analysis of large pipe networks. In order to develop a model based on the MTLM method was first necessary to define an algorithm for the automatic selection of circuits. For this reason, the algorithm of Breadth First Search (BFS) was used which is based on the theory of graphs. This algorithm was successfully used for the automatic selection of circuits in hydraulic pipe networks. The methods adopted for the implementation of these models used continuity equations in the junctions as well as equations of conservation of energy in the loops in terms of flow for each element of the system that resulted in a set of non-linear equations, relating flow with head lose. Once the systems of equations were linearized, the use of the KLU library for the solution of linear systems showed promising results for both methods investigated in this thesis. The validity and consistency of the results obtained herein by the proposed models were also confirmed through comparisons with results obtained by the software Epanet version 2.0. The results obtained through simulations with the goal to compare with results obtained in this thesis with the MTLM method and the method that uses a gradient algorithm showed satisfactory results with an efficient processing and computational time by both methods. The comparisons were performed with up to 1000 tubes, gathering new and robust data when compared to available literature that used only a small network with a number of tubes of less than 10% / Doutorado / Recursos Hidricos, Energeticos e Ambientais / Doutor em Engenharia Civil
8

Modeling Satellite District Heating and Cooling Networks

Rulff, David 20 December 2011 (has links)
Satellite District Heating and Cooling (DHC) systems offer an alternative structure to conventional, centralized DHC networks. Both use a piping network carrying steam or water to connect disparate building heating and cooling loads together, providing a platform for improving energy efficiency, reducing emissions, and incorporating alternative means of energy generation. However, satellite DHC networks incorporate thermal production units that are distributed amongst the buildings nodes, which offers greater operational flexibility and reduced capital cost savings for applications using existing building stock. This study was focused on the development of the methodology behind a comprehensive energy model that can assess the practical and financial viability of satellite DHC network scenarios. A detailed scenario application of the model demonstrated significant energy savings and investment potential. Additionally, environmental assessment methods and alternative generation technology were explored in supplementary studies of Deep Lake Water Cooling (DLWC) and building-scale Combined Heat and Power (CHP).
9

Modeling Satellite District Heating and Cooling Networks

Rulff, David 20 December 2011 (has links)
Satellite District Heating and Cooling (DHC) systems offer an alternative structure to conventional, centralized DHC networks. Both use a piping network carrying steam or water to connect disparate building heating and cooling loads together, providing a platform for improving energy efficiency, reducing emissions, and incorporating alternative means of energy generation. However, satellite DHC networks incorporate thermal production units that are distributed amongst the buildings nodes, which offers greater operational flexibility and reduced capital cost savings for applications using existing building stock. This study was focused on the development of the methodology behind a comprehensive energy model that can assess the practical and financial viability of satellite DHC network scenarios. A detailed scenario application of the model demonstrated significant energy savings and investment potential. Additionally, environmental assessment methods and alternative generation technology were explored in supplementary studies of Deep Lake Water Cooling (DLWC) and building-scale Combined Heat and Power (CHP).

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