simulation, Simtec was used to study effect of ultra fine water mist on
flame. This is a comprehensive simulation, with turbulent flow, particle
tracing, water mist evaporation, gas phase thermal radiation, particle
thermal radiation and turbulent combustion, etc, all computed. In order
to efficiently and reasonably well capture the water mist extinguish
effect on flame, while without considering all the detailed chemical
kinetics which will make the simulation extremely time consuming and
extremely hard to use in practical engineering, a particular turbulent
combustion model is developed in Simtec.
A series of simulations were made, with variation of water mist concentration level. The simulation shows a critical water mist concentration of about 0.3 g/L. The flame will survive when the mist concentration is below this value and extinguish when the mist concentration is above this value. This is in a reasonable good agreement with experiment measurement which gives a critical mist concentration of about 0.375 g/L.
a) 3D view, 0.2 g/L b) Temperature slice view, 0.2 g/L
Flame can survive when subject to water mist concentration of 0.2g/L
a) 3D view, 0.5 g/L b) Temperature slice view, 0.5 g/L
Flame is extinguished when subject to water mist concentration of 0.5 g/L