FIRE SUPPRESSION BY WATER-MIST SPRAYS: EXPERIMENTAL AND NUMERICAL ANALYSIS

Water-mist systems have become a promising technology in the fire-fighting field over the last twenty years. The present work is aimed at employing the available knowledge on water-mist sprays in an experimental and numerical analysis of the suppression mechanism. Therefore, a water-mist system has been operated within a typical fire case. Most notably, this latter is constituted by a heptane pool fire: experiments have been carried out inside a test chamber, where a set of thermocouples has conveniently been placed to evaluate the thermal transient at different locations of interest. Some free-combustion tests have been run as a benchmark to validate combustion models. Then, a typical water-mist nozzle has been inserted and activated to realize control, suppression and potential extinction of the generated fire. The recognized FDS (Fire Dynamics Simulator) and Fluent (R) codes have been challenged in reproducing the test case: thermal transient and suppression time have been considered as parameters for validation. Therefore, the water-mist spray has been modeled and the already mentioned results about its characterization have been implemented as initial or boundary conditions. Moreover, the fire scenario has been modeled as well. A good agreement between experimental and numerical results has been obtained, even under some approximations, with specific reference to combustion mechanisms.