Evaluation of energy efficiency of thrust hybrid bearings with active control of lubrication regime

Abstract

Fluid-film bearings design engineers focus on bearing reliability, life expectancy and energy efficiency as these elements have no alternatives when it comes to heavy loads and high rotor speeds where rolling-element bearings fail. Such bearings are, however, subjected to extensive wear during start-up/shut-down regimes and have load capacity limited by hydrodynamic force in the fluid film. Application of additional devices to form a lubricant feeding circuit allows elimination of these drawbacks by means of increasing load capacity with a hydrostatic component but only during transient regimes. The present paper investigates energy parameters, e.g. power loss due to friction, pumping and application of additional control and measurement elements in order to evaluate feasibility of application of active lubrication regime control in thrust hybrid bearings with a central feeding capillary. The paper features a mathematical model of the tribomechatronic system in question based on equations of hydrodynamics, contact mechanics, and theory of automatic control.