Numerical modeling of radiant heat attenuation through water mist

This paper describes the development of a two-phase radiation model for the prediction of radiant heat attenuation in fires by water mist. It has been especially developed for incorporation in comprehensive field models of fi re extinguishment by a water mist. The model predicts the opacity of the mi st by summing over the absorption and scattering coefficients for each part icle size present. A novel approach is proposed to reconcile the Eulerian f orm of the radiation transport equations with the Lagrangian particle track ing procedure. The model is fast, applicable to cases where the mist is mod eled following the Lagrangian concept, and it retains in evidence the physi cs of the problem while avoiding complex mathematics. Validation with exper imental measurements has shown that the model reproduces the water mist/rad iation interaction with sufficient engineering accuracy. Results also indic ate that radiation is a primary mechanism in fire extinguishment, since it contributes to nearly half of the total heat removal by the droplets.