Volume 5, Issue 2 (February 2008)
Varnish Formation in the Gas Turbine Oil Systems
The authors have investigated hydraulic and lubricating oil filter elements used in gas turbine systems which had varnish problems. The hydraulic filter elements were completely plugged with varnish and other degradation products at the first layer of the elements but the lubricating oil filter elements were not plugged with such contamination. However, the proofs of spark discharges of static electricity were found on the lubricating oil filter elements. This paper discusses the details of the investigation of the filter elements and one of the root causes of varnish formation in gas turbine oil systems.