Experimental investigation on spray characteristics of twin-fluid nozzle for water mist and its heptane pool fire extinguishing performance

Abstract

Water mist, which is an alternative to halon fire-extinguishing agents, can maintain the clean environments and prevent the huge fire loss in diverse industrial fields. In the present experimental study, the spray characteristics of a twin-fluid nozzle for water mist and its heptane pool fire extinguishing performance were investigated. As the spray characteristics, the SMD (Sauter Mean Diameter) of water mist, discharged water flux distribution, downward air flow velocity, and inlet pressures of fluids were measured and analyzed. Subsequently, through the fire extinguishing experiments using three different heat release rate conditions, the fire extinguishing map, extinguishing time, water consumption, and water mist effect on the mass loss rate were examined in detail. In addition, the experimental data using the twin-fluid nozzle were compared and discussed with those using the single-fluid nozzle reported in a previous study. Based on the present experimental data of fire extinguishments, particularly under high air flow rate conditions, the twin-fluid nozzle showed high fire extinguishing performance. Moreover, compared with a previous study using the single-fluid nozzle, it was found that the twin-fluid nozzle can successfully extinguish liquid pool fire with shorter fire extinguishing times, lesser water consumption, and lower inlet pressures. Based on the present results, it was found that the air flow of the twin-fluid nozzle is an important factor that determines and affects its fire extinguishing performance. Further, the twin-fluid nozzle was found to possess a significant potential to considerably improve the performance of water mist fire suppression systems.