A Study of the Fuel/Air Vapor Characteristics in the Ullage of Aircraft Fuel Tanks

摘要

The objective of the research was to study fuel tank ullage characteristics under various atmospheric and dynamic conditions. A test tank was constructed and mounted on a vibration table. The tank was filled with JP-4 fuel and withdrawn at various aircraft usage rates under controlled temperature and vibration. The fuel/air ratio of the ullage was measured with an infrared analyzer, and the data were recorded. A fuel/air ratio gradient was found in the ullage. It varied from a lean mixture (less than 1%) near the top of the tank, due to the inflow of air, to a rich mixture (as high as 12%) near the surface of the fuel, due to fuel surface oscillations. The testing indicates how this gradient is affected by changing the fuel withdrawal rate, fuel temperature, and vibrational excitation frequency. (Author)