Friction and Lubrication of Large Tilting-Pad Thrust Bearings

Abstract

Fluid film bearings have been extensively used in the industry because of their unbeatable durability and extremely low friction coefficient, despite a very low coefficient of friction dissipation of energy being noticeable, especially in large bearings. Lubricating systems of large tilting pad thrust bearings utilized in large, vertical shaft hydrogenerators are presented in this paper. A large amount of heat is generated due to viscous shearing of the lubricant large tilting pad thrust bearings, and this requires systems for forced cooling of the lubricant. In the dominant bath lubrication systems, cooling is realized by internal coolers or external cooling systems, with the latter showing some important advantages at the cost of complexity and also, potentially, lower reliability. Substantial losses in the bearings, reaching 1 MW in extreme cases, are a good motivation for the research and development aimed at reducing them. Some possible methods and their potential efficiency, along with some effects already documented, are also described in the paper.

Effects of the dimple geometry on the isothermal performance of a hydrodynamic textured tilting-pad thrust bearing

“…The use of variables without dimension allows the generalization of the problem, one poses: By putting these equations in equation (1) we obtain the Reynolds equation in non-dimensional form (Eq. 3):…”

“…Over the past years, extensive research activity has aimed at improving the performance of these components. There are two types fixed or tilting pads, the last bearings were invented by A. G. M. Michell in Australia and, independently, by A. Kingsbury in the USA [1]. Given the importance of these organs for rotating machines, several studies there are devoted to analyze their behavior and to study the different parameters which have an influence on their proper functioning (maximum pressure, load-carrying capacity and power loss).…”

Verification of the capacity of lubricating oil cooler system of turbine bearings

“…The shaft rotation generates excessive heat in the bearings, which is removed by the lubricating oil. The heat from the lubricating oil can be excessive [4] and needs to be dissipated by a cooler system [5], most often employing running water as a cooling fluid.…”

Analysis on the escape phenomenon of oil mist from turbine lower guide bearing based on VOF model

“…Walicka et al 12 discussed the influence of both bearing surfaces roughness and porosity of one bearing surface on the pressure distribution and load-carrying capacity of a thrust bearing surfaces. Wasilczuk 13 presented lubricating systems of large tilting pad thrust bearings utilized in large, vertical shaft hydrogenerators in this paper. Akbarzadeh 14 studied the numerical calculation method of heat flow in the oil tilting-pad journal bearings of a vertical hydropower station, and used this method to analyze the effects of pad number, preload factor, pivot position and shaft rotational speed on the bearing lubrication performance.…”