Numerical simulation of ultra-fine powder extinguishing agent injection process

Abstract

The process of pressurized injection of ultra-fine powder extinguishing agents (UPEA) and the effect of injection from the nozzle directly affects the spatial dispersion characteristics and the effectiveness of fire extinguishing. Combining CFD simulations and experimental measurements, the UPEA pressurized injection process and injection effects were investigated. The transient process of injection is divided into three stages, initial injection stage, steady injection stage, and post-injection stage. The post-injection stage is divided into a slow decay process and a residual gas release process. Investigating the effect of different filling conditions on the effectiveness of particle injection. In the stable injection stage, the higher the filling ratio, the lower the mass flow of UPEA particles at the same filling pressure. At the same filling ratio, the higher the filling pressure, the higher the mass flow of UPEA particles. The maximum mass flow of the UPEA particles was 5.38 kg/s at a filling ratio of 20% and a filling pressure of 3.6 MPa. The steady injection time is mainly influenced by the particle filling ratio.