Abstract: Abstract: Simulation models were developed for an aircraft fire extinguishing system using Amesim software. The influence of the parameters such as the filling pressure, the temperature of the fire extinguishing agent, the roughness of the pipe, the diameter of the nozzle, and the diameter of the branch pipe of the pipeline were studied. It is found that under the filling mass of 5.34 kg of fire-extinguishing agent, the spray mass curves of fire-extinguishing agent under the filling pressure of 4, 5, and 6 MPa are similar. The lower the temperature of the extinguishing agent, the slower the spray rate. The spray time of -50 ℃ fire extinguishing agent is about 2.5 times that of -10 ℃. Roughness also has a significant effect on the amount of fire extinguishing agent sprayed. The lower the roughness, the faster the spray amount. The quality curve of fire extinguishing agent under the roughness of 0.13 mm and 0.20 mm is similar. The nozzle diameters of 16 mm, 17 mm and 18 mm have little effect on the overall fire extinguishing agent spray quality of the system, but the flow distribution between the nozzles will be affected by the change of the nozzle diameter. When the diameter combination of the long branch pipe connecting 3 nozzles and the short branch pipe connecting 2 nozzles is (16, 14 mm) and (20, 12 mm), the ratio of the amount of fire extinguishing agent sprayed from the two branch pipes is close to 1.

Key words: Key words: aircraft fire prevention, fire extinguishing system, extinguishing agent flow, two-phase flow