Abstract:  In order to thoroughly understand the characteristics of multiphase fluid transportation in the compressed air foam fire extinguishing system (CAFS) pipe network, simulation of the entire pipeline transportation process of a compressed air foam fire extinguishing system used for converter transformer protection was performed using Fluent software. On the basis of verifying the accuracy of numerical simulation, the apparent viscosity and pressure changes of fluids in typical areas such as straight pipe sections, elbows, and tees in the pipe network were analyzed. It is found through research that the compressed air foam fluid flowing in the pipe network will change due to its own parameters during the flow process. Therefore, the pressure drop of the pipe network and other results show complex characteristics that are affected by multiple factors such as expansion rate of foam and flow rate.

Key words: converter transformer, CAFS, pipe network, viscosity, pressure drop