Effect of Structure on Reactor Performance in Fuel Vapor Catalytic Inerting System for Aircraft Fuel Tanks

Fuel vapor catalytic inerting technology is considered to be the most promising approach to inertize aircraft fuel tanks in the future. However, the complex and fluctuating inlet operating conditions have led to issues such as low reaction efficiency and a narrow operating range for the core component, the catalytic reactor. To address these challenges, a simulation model of a two-temperature porous media catalytic reactor was established using Fluent 17.0 software. This model coupled gas–solid heat transfer and chemical reaction through user-defined functions (UDF) and user-defined scalar (UDS). The model's accuracy was verified using a self-built experimental platform. The impact of three different reactor structures—cylindrical, expanded, and tapered—on reactor performance under the same reaction conditions was compared. Operation parameters, such as the preheating temperature of the reaction gas, fuel vapor concentration (FVC), and oxygen concentration (OC), were also studied. The results showed that the expanded-shaped catalytic reactor improved the conversion rate of fuel vapor, while the tapered-shaped reactor made the temperature distribution inside the reactor more uniform and suppressed hotspots. Additionally, increasing the inlet gas temperature, FVC, and OC had a promoting effect on the catalytic reaction. Due to the adoption of appropriate cooling methods to solve the problem of reactor temperature surges, this paper recommends designing the catalytic reactor into an expanding shape to improve fuel vapor conversion rate and improve inerting system performance. The findings of this study are significant for promoting the application of catalytic inerting technology in RP-3 aviation fuel.