Paper 30: Lubricants for Hot Environments with Special Reference to Aero Gas Turbines Operating under Severe Conditions

Abstract

This paper reviews some of the problems associated with lubricants for bearings and gears in aero gas turbines operating under severe conditions. The physical limitations imposed on oils by the requirement for high thermal stability are discussed in relation to the necessity for adequate gear lubrication at elevated temperatures. An outline is given of the effects which lubricant additives can have on oil performance in bearing and gear tests. Some adverse side effects of otherwise beneficial additives are pointed out and finally a brief account is given of the methods employed to improve the resistance of oils towards oxidation at high temperatures.