Suppression of a non-premixed flame behind a step

Abstract

suppression effectiveness under conditions that relate to field applications. In this study, a laboratory-scale facility has been developed to screen the suppression effectiveness of agents that are delivered in a transient fashion, such as solid propellant gas generators. The facility features a pool fire stabilized behind an obstruction, which is known to be a highly challenging suppression configuration. The character of the flame and the impact of the air flow, propane flow, obstruction geometry, and rate of agent addition on the amount of material needed for suppression are examined for N2 and CF3Br. The impact of the injection process on the flowfield and the transport of the agent downstream are examined. A simple mixing model is useful to explain the observed trend of decreasing suppressant mass fraction with increasing injection duration, even for agents as different as CF3Br and N2. Direct numerical simulation of the suppression event is shown to successfully predict the quantity and rate of N2 required to extinguish the flame based upon a published global reaction rate for premixed propane/air flame propagation.