The evaporation of sprinkler droplets is an important phenomena in fire simulations both for heat removal from the gas and for heat removal from surfaces. In this paper, we address the problems of potential numerical instability and super-saturation that may occur in explicit time integration of the droplet equations. Two novel numerical approaches are developed and evaluated. The first is based on an analytical solution that relaxes the cell composition and temperature toward the equilibrium values. The second method is an implicit solution to the droplet equations. The two approaches are implemented in the Fire Dynamics Simulator (FDS) and verified and validated using both single droplet and practical sprinkler calculations. Ultimately, the implicit approach is demed the most cost effective for practical fire simulations.
Conference Dates: June 12-16, 2017
Conference Location: Lund, -1
Conference Title: International Symposium on Fire Safety Science
Pub Type: Conferences
FDS, droplet evaporation, sprinklers, watermist