THE DOUBLE-DIFFUSIVE CONVECTION IN THE PROCESS OF WATER MIST FIRE SUPPRESSION

In the research of the mechanism of water mist fire suppression, thermal buoyancy has important effects on smoke movement and temperature distribution, but the effects of the smoke diffusion are less considered. In this paper, a computational method couple dual reciprocity boundary element method (DRBEM) with finite volume method (FVM) is developed to study the thermal and smoke diffusion effects on the smoke movement, temperature and CO2 concentration distribution. And the interaction between the smoke and a water spray is calculated using FVM with the PSIC scheme. The DRBEM is employed to calculate the inner temperature of the droplet and radius variation, and the results show that when the droplet radius less than 1mm, the uniformly temperature assumption is reasonable. Numerical results also show the gradients of temperature and smoke concentration drive double-diffusive convection have different effects on the smoke temperature and CO2 concentration with and without water spray.