关键词: |
Fuel tanks, Aircraft equipment, Gas generating systems, Rare gases, Fibers, Membranes, Permeability, Protection, Fire protection, Explosions, Oxygen, Nitrogen, Separation, Gas flow, Life cycle costs, Polymers, Methylenes, Transport aircraft |
摘要: |
The program successfully demonstrated the feasibility of using permeable-membrane, hollow fibers to generate an inert gas to protect the aircraft fuel system against fire and explosion induced by natural sources or combat. The initial contract requirements included a flight demonstration of an onboard inert gas generator system (OBIGGS) using an Air Force KC-135A aircraft. The design of an inert gas generator (IGG) is highly dependent on the flight profile, engine characteristics, and fuel system designs. Mission analysis translated these parameters into an 8 lb/min inert gas generator that produced less than 9-percent oxygen. A life-cycle cost (LCC) analysis compared the state-of-the-art liquid nitrogen (LN2) system utilized on the C-5A aircraft against the IGG system designed for the KC-135A. Results showed the IGG system reduced LCC by 60 percent. Further, the IGG system eliminates the logistic constraints imposed by the use of LN2, thus allowing unrestricted deployment of the aircraft. A second LCC analysis was conducted in which the permeable-membrane system was compared against the blue foam design used on the C-130 aircraft. The LCC analysis shows great advantage for OBIGGS over blue foam. The externally pressurized polymethylene hollow fiber bundles are expected to exceed the 20-year life expectancy of the aircraft. |