Impact of Pipe Diameter on the Discharge Process of Halon1301 in a Fire Extinguishing System with Horizontal Straight Pipe

In aviation fire extinguishing systems, the extinguishing agent is stored in a bottle, which is pressurized by nitrogen. When fire occurs, the agent is discharged via pipe and nozzle to the target compartment. The geometry of the pipe has a significant impact on the discharge process, and merits study. In this study of the discharge process of halon1301 using pipes of different diameters, the pressure distribution was significantly influenced by varying pipe diameter. Contributions to pressure drops through the valve/pipe/nozzle were approximately 2%, 8%, and 90%, respectively, when the pipe diameter was larger than the nozzle diameter. The contribution through the pipe increased, and the contribution through the nozzle decreased, as the pipe diameter became smaller. When the pipe diameter was decreased to the nozzle diameter, pressure drops through the valve/pipe/nozzle were 10%, 45%, and 45%, respectively; there was an increased pressure drop through the pipe. Distinctions in pressure distribution led to temperature differences; when there were more pressure drops through the nozzle, the temperature in the pipe was lower.