Modelagem termo-hidrodinâmica de mancal cilíndrico radial submetido à condição de lubrificação variável

Abstract

Cylindrical hydrodynamic bearings are essential components in rotating machines, used in applications ranging from small motors to large turbo generators. They operate based on the principle of a thin oil film that separates a rotating shaft from the bearing, preventing contact between the surfaces. Studies on cylindrical bearings usually consider an adequate supply of lubricant. However, it is crucial to analyze the phenomenon of oil starvation to understand the influence of lubrication conditions on bearing performance. Various numerical models have been developed to represent the behavior of hydrodynamic bearings, classified according to the lubrication condition: hydrodynamic, thermohydrodynamic, elastohydrodynamic, and thermoelastohydrodynamic. In these models, the supporting pressure is generally determined by solving the Reynolds Equation. In this work, two formulations were developed - the reduced Reynolds equation and $p-\theta$ - to represent this machine component. In addition to validation with the data provide by literature, experimental validation of the model is necessary. For this, a bearing was designed and manufactured, capable of being instrumented to monitor variables that will be compared with the simulation. Sixteen thermocouple sensors, equally spaced along the circumferential length of the bearing, were used to monitor the oil film temperature. A similar scheme was adopted for pressure data acquisition, with sixteen pressure transducers distributed similarly to the temperature measurement scheme. The obtained results demonstrated that the THD model obtained a good representation of the behavior of the cylindrical bearing.