Frangible Coatings for Mitigation of Fuel Coking

The efficient and reliable operation of military aircraft is vital to maximize force projection in current and future combat space. As the performance of aircraft is pushed beyond current limits, the aircraft runs faster and more efficiently; as a result, the operating temperature of engines rises. Innovative cooling mechanisms have been developed that use jet fuel as coolant before it is combusted. Consequently, the temperature of the fuel can reach in excess of 600 F. In combination with a small amount of dissolved oxygen in the fuel stream, autoignition of the fuel forming carbonaceous particles and free radical that deposit onto the fuel lines of the engine. The buildup of deposits is most prevalent in the vicinity of the fuel injectors which have the highest time at temperature exposure and last chance screens. The last chance screens catch residual particle contamination and have the narrowest fuel passages. Overtime the carbon films build up over the fuel lines, reducing fuel flow and decreasing its effectiveness as a coolant. It is vital to prevent the buildup of carbon on the surface to improve efficiency and decrease maintenance costs. Triton systems will develop a coating for fuel line components that will promote delamination of coking films during normal aircraft operation. The coating will reduce maintenance of vital components and improve reliability of aircraft engines. Tritons innovative deposition approach will produce a uniform, crack-free coating. The deposition technique is widely scalable to increase the economic viability of the end product. This process circumvents the slow, expensive gas phase deposition techniques used for coatings on complex geometry. Materials selection and fabrication conditions will be optimized to maintain high performance and durability from environmental stresses. In phase I, prototypes of promising materials will be fabricated for initial frangibility measurements using fuel with a composition mimicking real operating conditions. This will open a clear pathway for production at high throughput for phase II requirements.