Analysis of the two-flux model for predicting water spray transmittance infire protection application

An investigation is carried out to assess the two-flux model for evaluating the attenuation ability of a water spray curtain in fire protection. Trans mittances calculated with this model are compared with the "exact" discrete ordinates solutions for a range of water curtains under practical conditio ns. The results show the unsuitability of the two-flux method under a colli mated incidence boundary condition, even if some improvements could be expe cted with very small droplets. Whereas the diffuse incidence type provides relatively better results, it is moi-e reliable for transmittance calculati ons.