Liquid nitrogen injection into aviation fuel to reduce its flammability and post-impact fire effects

Abstract

The finite volume method was used to study the characteristic of contaminated aviation fuel with the aim of reducing its flammability and post-impact fire. The flammability levels between pure Jet A-1 and contaminated Jet A-1 are compared using their flashpoints and fire points before and after the introduction of Liquid Nitrogen. Upon heating different mixing ratios (4:1, 3:1, and 2:1), results are analyzed to identify the best volume ratio exhibiting the highest reduction in flammability. Analysis shows that the mixing ratio of 2:1 not only froze but increased the flashpoint of the mixture from (48 ˚C–50 ˚C) to 64 ˚C. For the mixing ratio of 3:1, there was a rise in flashpoint to about 56 ˚C and partial freezing was seen at the topmost surface. At a mixing ratio of 4:1, it was observed that the effect of liquid nitrogen on Jet A-1 was minimal leading to a slight rise in its flash point (50 ˚C). Thus, liquid Nitrogen had a substantial effect on the flammability and flash point of Jet A-1 when mixed in the ratio (2:1) with a freezing time of 30 seconds and an unfreezing time of 17.5 minutes. Hence, Liquid Nitrogen can be used for the flammability reduction of Jet A-1.

Keywords

• post-impact fire
• flashpoint testing
• CFD analysis
• fire safety
• contamination
• FEM