Physical, performance, and chemical changes in turbine oils from oxidation

One of the primary factors in determining the life and performance of turbine oils is its oxidation stability. Oxidation can cause a host of problems for in-service turbine oils, such as sludge, deposits, lacquer, and varnish formation. There is limited published research on the performance of turbine oils once oxidation begins. This paper presents data on the relationship between several turbine oil characteristics during the oxidation process by focusing on the measurable physical and chemical changes that occur. Five turbine oils were chosen, each employing different antioxidants and base oil refining technologies to represent a typical selection of commercially available turbine oils. A 49-day experiment was completed in which the oils were subjected to a controlled and accelerated oxidative process under laboratory conditions. Throughout the testing period, samples were drawn and a range of chemical, physical, and performance tests were performed. The data obtained from this experiment identify several correlations that relate to the performance of each oil. These data are useful in understanding the relationship between turbine oil oxidation and fluid performance and will help end-users in selecting and optimizing their turbine lubricant.