Aircraft nacelle fire extinguishing system spray and dispersion simulation

Simulation is an essential technique used to assess the dependability of fire suppression systems in aircraft engine nacelle. The fire extinguisher system's pipeline and nacelle models are constructed with CFD. Simulation calculations are then performed to analyze the flow of the extinguishing agent in the pipeline and its dispersion within the nacelle. The simulation results indicate that pipelines with a simple structure and shorter length achieve higher pressure during the spraying process and exhibit a greater mass flow rate. The maximum mass flow rate for nozzle 1 is 7.3 kg/s, while for nozzle 2, it is 5.1 kg/s. The spread of extinguishing agent concentration is significantly influenced by wind speed and the existence of ribs. The presence of ribs can prolong the duration of the concentration of the extinguishing agent in the recirculation zone. The extinguishing agent concentration values at 12 measurement points within the nacelle meet the standard requirements, demonstrating the rationality of the fire extinguishing system's design.