Future Research

Full-Scale Flammability Measurements
A large amount of data has been collected that quantifies the total hydrocarbon concentration (THC) of a flammable center wing tank (CWT) ullage under different conditions. The vast majority of this data was not obtained from an operational aircraft fuel tank ullage during normal operating conditions. In addition, little work has been done to investigate the flammability evolution within and aircraft's outer wing tanks (WT). This gap in the knowledge base for aircraft fuel tank flammability has been a potential source of discrepancy in determining the best method of approaching fuel tank flammability reduction. The FAA's 737 and 747 full-scale test articles will be utilized to study both CWT and WT flammability by fueling the tanks to different fuel loads and running the air cycle machines under various conditions. The data from these tests should assist our ability to more accurately determine/predict expected flammability conditions within aircraft fuel tanks.

Jet-A Vapor Simulate Ignition Testing
A 20 liter spherical combustion vessel has been constructed and is being utilized to determine a suitable stimulant to utilize in ignition testing in the hopes gaining the ability to generate approximate full flammability curves at various pressures and oxygen concentrations for Jet-A fuel vapors. Simulates used previously by other researchers have included hexane and a mixture of hydrogen and propane. While these provide for an adequate simulate at sea level conditions and a 21% oxygen environment, it is unknown how they will perform at reduced pressures and oxygen concentrations.

Further research will be forthcoming in the area of fuel flammability in the continued efforts to further define fuel tank flammability and to improve upon our existing fuel tank flammability models.