| Objective: ||Develop enhanced jet-fuel-lubricated bearings for small aircraft and missile turbine engines.
|| Description: ||Advanced fuel-lubricated bearings in missile engines are an attractive approach over conventional oil-lubricated bearings due to substantial benefits that result from the elimination of the conventional recirculating lube system. Benefits include reduced engine cost and weight, reduced specific fuel consumption, and increased range. These benefits are consistent with the goals of the efficient small scale propulsion concept and other small expendable engine concepts being considered by the Air Force. However, jet fuel does not possess the lubricating qualities that typical turbine engine oils do, particularly when the engine bearings are required to operate at extreme conditions of load, speed, and temperature. Hence, the antiwear additive tri-cresyl phosphate (TCP) has been successfully used in JP-10 fuel to enhance its tribological properties. Also, due to the poor lubricating properties of fuel, fuel-lubed bearings typically use advanced materials such as carbon-carbon (C-C) composite cages and Si3N4 rolling elements to reduce bearing heat generation and to improve overall bearing performance. These materials offer significant bearing performance benefits over conventional materials and hence, it is desired to further develop them for fuel-lubed bearings. Other issues include the necessity to green run the engine prior to use and long-term storage. The objective of this SBIR topic is to develop enhanced fuel-lubricated bearing technology that addresses the issues identified above. Specifically, ideas are being sought for 1) alternative methods for pre-seasoning or conducting engine green run of fuel-lubed bearings, 2) developing an effective long-term storage methodology for engines with fuel-lubed bearings, 3) maturing manufacture of C-C cages for fuel-lubed bearings, or 4) exploring optimum antiwear additive technology for fuel lubricants.
|| ||PHASE I: Develop technological concept and demonstrate feasibility of technologies that address performance and lubricity issues of fuel-lubricated bearings. Interaction with small engine manufacturer is highly recommended.
|| || ||PHASE II: Develop, test, and demonstrate an operable prototype that fulfills the technological concept. Establish a viable business model to produce and support the application of the product.
|| ||DUAL USE COMMERCIALIZATION: Military application: Technology developed in this program will have several military applications, including cruise missiles, decoys, and small aircraft engines. Commercial application: Technology has potential for small commercial or general aviation aircraft turbine engines.
|| References: ||1. Forster, N., Rosado, L., Brown, J., and Shih W., "The Development of Carbon-Carbon Composite Cages for Rolling Element Bearings," <i>Trib. Trans.</i>, Vol. 45, No. 1, pp. 127-131, 2002.|
|Keywords: ||rolling element bearing, gas turbine engine, fuel lubrication, antiwear additives, C-C cages, bearings, jet fuel lubricity|