Lift Fan Gearbox Corrosion Monitoring System

State-of-the-art gas turbine engine bearing and gearbox steels are subject to significant rejection rates due to corrosion. Recent statistics from the engine overhaul depots indicate that greater than 50 percent of the bearings are rejected. Approximately 40 percent of these rejections are due to corrosion. For naval applications, the rejection rate is even higher. Such corrosion leads to premature surface crack initiation and spalling that cascades into accelerated surface damage, high vibration, and eventual catastrophic bearing failure. It is the goal of this project to develop a highly sensitive, compact, light-weight, low-power, reliable, safe, easy to use, inexpensive to own and maintain, x-ray fluorescence analyzer for direct, trace measurement of trace contaminants in gearbox lubricants. The proposed compact, direct, trace element analyzer is based on a number of developments at X-ray Optical Systems (XOS) over a several year period. This includes unique doubly curved crystal (DCC) monochromating and focusing x-ray optics and compact, highly reliable X-Beam x-ray sources. The gearbox lubricant analyzer can be used on the tarmac or flight deck during routine or preflight inspections or potentially can be mounted on aircraft for continuous on-line lubricant monitoring. This new technology has many important potential military and civilian applications.BENEFITS: Given the proposed operating regime of the F-35 Joint Strike Fighter (JSF), there are clearly environments containing corrosion elements like salt water/vapor. The proposed gear box lubrication monitoring product can be designed for use in routine inspections, periodic inspections or even in flight. A successful cost-effective, low power, compact, non-destructive tool for verifying proper gearbox operation would decrease propulsion failure and aircraft mishaps. An additional benefit can be realized if the gear box monitoring system decreased the frequency of inspections because the proposed system was used to improve the process. The initial users of the analyzer would be the aircraft and propulsion manufacturers who supply the engine, lift system and gearbox hardware to the Department of Defense for the F-35 such as Rolls Royce in Indianapolis, Indiana. In some cases, the outside firms that provide evaluation services would also utilize this instrument. Follow on uses of the monitoring technology would be other advanced propulsion and ground based power generation applications where performance, reliability and robustness are important.