An assessment of the importance of secondary spray on a water sprinkler scenario

Recent development efforts have resulted in new models that are capable of predicting water spray interactions with solid surfaces for a wide range of drop sizes and velocities. These models provide a reasonable approximation to single drop impact events, and significantly improve the expected accuracy of the splash. The models are implemented in the Vulcan software, a CFD code for fire modeling. We wanted to understand how important the splash is to a suppression scenario and the implications of common simplifying assumptions. A scenario with several rectangular objects located beneath a water suppression system is examined. This scenario was designed to be representative of an industrial fire and suppression situation. We compare the deposition masses on the surfaces for three cases, one with the recently developed model, another assuming no splash, and another assuming all splashing drops eject an excessive fraction of their mass. The results of the higher fidelity predictions compared with the more commonly employed and simpler assumptions suggest the importance of splashing to the outcome of an industrial water sprinkler fire suppression event.