Candidate: Desyel Ferronatto
Program: UFSC / POSMEC
Date: November, 2011
Advisor: Victor Juliano De Negri
Abstract: With the growing need to increase accuracy and speed response of the hydraulic positioning control systems, the detailed research of the isolated behavior of hydraulic components has grown quite considering that the detailed behavioral knowledge of each component can help to understand the deviations in system performance. This thesis conducts a research on the behavior of directional continuous control valves, specifically spool valves, which are widely used in hydraulic position control systems, for example, in positioning control systems of the distributor ring in hydroelectric power plants. The study evaluates the influence of internal geometric parameters such as radial clearance, overlap length in the hydraulic behavior of the directional control valves. A theoretical model based on the internal fluid flow through orifices is developed that, combining modeling of the internal geometry and discharge coefficient models, reproduces both pressure and leakages inside the valve. The modeling which includes different geometries and valve nominal size is validated by comparison between experimental data obtained from standardized tests by ISO 10.770-1 Standard and simulation results obtained with theoretical model. The conclusions lead to establish a global view of the influence of radial clearance, overlap, eccentricity, chambers volume and pressure settling time in behavioral characteristics such as pressure behavior, internal leakage magnitude, hysteresis and hydraulic center position.
FERRONATTO, D. Análise da influência de parâmetros geométricos em curvas características de válvulas de controle contínuo direcional. 2011. Dissertação (Programa de Pós Graduação em Engenharia Mecânica), 153 p. Universidade Federal de Santa Catarina.
