EXPERIMENTAL STUDY OF THE RESPONSE OF A PRESSURE RELIEF VALVE FOR SLOW AND FAST BLOCKAGE EVENTS

Marcos José Babilonia¹; Juliana Kuhlmann Abrantes¹; Luis Fernando Alzuguir Azevedo¹

¹ Pontifícia Universidade Católica do Rio de Janeiro

doi:10.20906/CPS/COB-2015-0394

Resumo

Pressure relief valves (PRVs) are extremely important devices used to ensure operational safety in pipeline systems and their integrity in the case of a sudden blockage event. Depending on the nature and duration of the blockage event, on valve's characteristics and on the length of the duct, the dynamic behavior of the valve, i.e., its response time and discharge coefficient as a function of lift fraction can vary considerably. This kind of detailed information about the transient is not specified in norms and is rarely made available, not even by the manufacturer. In any case, a complete dynamic characterization of the PRV can be crucial for the optimization of a given system. Due to the importance of those valves, several research works focusing on their behavior can be found in the literature; however, most of them present simplified models, considering steady flow regime for different fixed lift positions, which may not be a good approximation, especially for very fast transient events. The work presented here comprises the first stage of an experimental investigation of the behavior of a small-scale plexiglass spring-type PRV model. The goal is to perform a series of measurements based on both steady and transient approaches. Lift displacement, pressure, velocity field and discharge flow rate measurements can be acquired in this test section, with the final goal of comparing the coefficient of discharge versus lift displacement behavior observed from the steady state and transient measurements. In the initial stage described in this article, displacement and pressure data, as well as some preliminary flow field results obtained with Particle Image Velocimetry, are presented for the transient approach, considering both a slow and a very fast blocking event in the piping system. The experimental setup consists of a closed water circuit, with a progressive cavity pump generating the main flow and a coaxial valve placed downstream of the PRV model, to cause the sudden blockage when energized. In order to inves

Palavras-chave: Pressure relief valve; Particle Image Velocimetry (PIV); Transient discharge flow