Computational Flow Analysis of Ultra High Pressure Firefighting Technology with Application to Long Range Nozzle Design

摘要

Although aqueous fire fighting agent compositions have undergone considerable evolution in recent decades, agent stream optimization has lagged behind in development. A Computational Fluid Dynamic (CFD) modeling study analyzes Ultra High Pressure (UHP) jet stream characteristics as a function of nozzle flow conditions and fluid composition. A CFD sub-model analysis is also conducted to determine sensitivity to certain modeled assumptions. In addition, a steady co-flow augmented nozzle concept is analyzed to demonstrate nozzle enhancements to prolong jet reach. Experimental Laser Doppler Velocimetry (LDV) and Phase Doppler Particle Analysis (PDPA) field sampling provide computational boundary conditions and general observed flow characteristics where applicable. Results show flow factors that increase jet Reynolds and Weber number also increase jet reach. Multiphase, turbulent, and non-uniform droplet dynamic CFD sub-models affect solutions, but typically as a higher order effect. Steady co- flow nozzle results depict a negligible effect on extending jet reach. Further experimental validation data and CFD model development is required to create a dependable agent application optimization tool for the fire research community.