Small-Scale Experimental Study on Smoke Blocking and Thermal Insulation Performance of Water Mist Sprinkler

To investigate the performance patterns of high-pressure water mist sprinklers with different flow coefficients in smoke containment and thermal insulation during fire suppression, this study conducted droplet size experiments and small-scale fire tests at 8 MPa pressure using six sprinkler types with flow coefficients (K) of 0.5, 0.7, 1.0, 1.2, 1.5, and 2.0. These findings were systematically analyzed in conjunction with FDS numerical simulations. Droplet size results indicate optimal atomization for K = 1.0, 1.2, and 1.5 sprinklers, producing fine droplets with concentrated distribution. Small-scale experiments and simulations further compared their smoke suppression and heat insulation performance. Findings show K = 1.5 delivers superior smoke suppression and cooling effects, reducing protected area temperatures by 20~45 °C compared to other conditions while minimizing smoke spread. Although visibility was slightly lower than at K = 1.2 due to droplet size and particle count, the overall performance was superior. This study conclusively identified K = 1.5 as the optimal flow parameter, providing experimental evidence and theoretical support for the engineering application of high-pressure water mist sprinklers.