Study on the deoxygenation characteristics of RP-5 aviation fuel via nitrogen-enriched air scrubbing inerting.

This study investigates the performance of an active fuel tank inerting method utilizing Nitrogen-Enriched Air (NEA) scrubbing. Using RP-5 aviation fuel, an Eulerian-Eulerian two-fluid CFD model was established and experimentally validated to investigate the gas-liquid two-phase flow and mass transfer characteristics. The study focuses on the effects of microscopic bubble diameter, NEA oxygen concentration, and temperature on the gas-liquid mass transfer driving force, oxygen mass transfer coefficient, and oxygen volumetric mass transfer coefficient. The results indicate that reducing bubble diameter is the most significant means of enhancing mass transfer; reducing the bubble diameter from 2.5 mm to 1.0 mm resulted in an approximate 3.9-fold increase in the oxygen volumetric mass transfer coefficient. NEA oxygen concentration primarily affects the mass transfer driving force but has no significant impact on the mass transfer coefficient. NEA temperature exhibits a competitive effect between thermodynamics and kinetics: although elevated temperatures enhance the molecular diffusion coefficient, the increased solubility of gases in RP-5 aviation fuel leads to deteriorated final deoxygenation performance. This study reveals the coupled heat and mass transfer mechanism of RP-5 aviation fuel scrubbing inerting, providing a theoretical basis for the optimization of gas source parameters and thermal management design in airborne inerting systems.