All pipeline systems are susceptible to water hammer that can cripple critical infrastructure. One effective method to relieve excessive waterhammer pressures in pipelines is to use air chambers. This study aims to develop an empirical procedure for the quick analysis of penstock-turbine systems to determine dimensions and operating conditions of air-chambers that can effectively diminish the transient phenomena after sudden changes of flow rate in the system. A numerical study has been carried out by obtaining repeated solutions for variable system parameters using a commercial software. The relief brought by air chambers is found to approach to an asymptotic value for increasing chamber volumes. It is possible to determine the required chamber volume for a given discharge to limit the waterhammer pressures at a prescribed level in a given penstock-turbine system using the charts produced in the study.

Orientador: Paulo Vatavuk / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-11T08:47:49Z (GMT). No. of bitstreams: 1 Souza_EdsonVictorde_M.pdf: 1243495 bytes, checksum: 65a1b651d2f304cfca69e91ab51e9514 (MD5) Previous issue date: 2008 / Resumo: O estudo do transitório hidráulico em condutos forçados tem grande relevância em projetos de sistemas de tubulações. A quantificação das pressões máximas e mínimas é de fundamental interesse para o projetista, a fim de que este possa dimensionar a tubulação e/ou prever dispositivos de proteção, cuja finalidade é amortecer as variações de carga, prejudiciais à vida útil da instalação. Neste trabalho optou-se pelo estudo de um destes dispositivos, o reservatório hidropneumático, que protege as instalações contra sobrepressões e subpressões, impedindo assim a descontinuidade do escoamento quando o sistema de bombeamento é desligado ou quando ocorre um fechamento rápido de válvula de bloqueio. O objetivo principal da presente pesquisa é o de formular tabelas e gráficos de aplicação para o pré-dimensionamento de reservatórios hidropneumáticos para a atenuação de transitórios hidráulicos em sistemas de condutos forçados, facilitando, desta maneira, o trabalho dos projetistas na escolha deste tipo de dispositivo de proteção de sistemas hidráulicos / Abstract: The evaluation of hydraulic transients is very important in the design of pipe networks. The determination of the maximum and minimum pressures is of great interest to the designer, so that he can size the pipes and/or design protection devices, with the objective of decrease head variations, that can decrease the instalation life. In this work, one of those devices was chosen for study, the air vessel, that protects the instalation against overpressures and underpressures, avoiding the interruption of the flow when the pumping system is turned off or when a valve closes too fast. The present work has the main objective of making charts and graphs of application for pre-sizing of air vessels to the mitigation of Waterhammer in pressure pipes by facilitating, in this way, the work of designers in choosing this type of protection of hydraulic systems / Mestrado / Recursos Hidricos / Mestre em Engenharia Civil

This thesis describes the design work for the measurement of air values. The first part describes the airflow, pressure build-up in pipes and losses due to airflow losses. There is also a description of fans and explain their characteristics depending on the pressure generated by airflow. The next part describes the design of the measuring chamber, electronics and control for fully automatic measurement of air quantities.