Análise de modelos termohidrodinâmicos para mancais de unidades geradoras Francis

Abstract

This work is dedicated to the computational modeling of the hydrodynamic bearings present in a Francis hydropower unit. In order to represent the dynamic behavior of these bearings, a thermohydrodynamic approach is used, in which the thermal effects due to the viscous friction of the oil film are computed through the simultaneous solution of the Reynolds and energy equations. Using simplifying hypotheses, the four hydrodynamic bearings of the hydropower unit are analyzed, namely a combined thrust and guide tilting-pad bearing, an intermediate guide tilting-pad bearing, and a cylindrical guide bearing. The discretization of the partial differential equations of the bearings is performed by using the finite volume method. In order to verify the consistency of the numerical results obtained in the present work, the results provided by the manufacturer were used, as well as the experimental data measured by the monitoring system of the hydropower unit. The obtained results demonstrated to be promising since they have a good correlation with the information extracted from the manufacturer and experimentally. It is worth mentioning that the present work was developed under the R&D project Robust Modeling for the Diagnosis of Defects in Generating Units (02476-3108/2016) conducted by ANEEL (Brazilian Electric Energy Agency). This project is carried out at the Federal University of Uberlândia, Brazil, with the financial support of the companies CERAN, BAESA, ENERCAN, and Foz do Chapecó.