Study On The Inhibition Of Vertical Spread Flame Ejected From Window Of High-Rise Building

High-rise apartment fires are perhaps the most dangerous residential fires. Within high-rise buildings, flames and smoke can travel through ductwork, between interior walls, and up elevator shafts and stairwells. One of the fastest ways a fire spreads to other floors is along the exterior of the building due to open windows. Flame spread up vertical walls has been studied experimentally and computationally for years. but the variation of flame spread along the external wall and CO concentration in building should be research when presence of a balcony, at the same time there is little study on the reduction of vertical flame spread by water mist curtain. So this paper foucuses on providing a quantivitive analysis on the reduction of flame spread due to the effect of balcony/water mist curtain by numerical method.(1) In this paper, the author numerical Study on the interaction of balcony/water mist and flame ejected from Window of high-rise building by computational fluid dynamics software FDS. The turbulence is Based on taking large Eddy Simulation (LES). The development of the turbulent diffusion flame is simulated using mixture fraction combustion model. As the radiation spectrum of soot is continuous, it is possible to assume that the gas behanves as a gray medium, and the absorption and scattering coefficients are based on Mie theory. The two-phase interactive transient process is based on the Eulerian-Lagrangian formulations for the gas phase and liquid (droplets) phase, respectively. Space variable is in form of second-order finite difference scheme while time variable is in form of indicating the forecast and amend, a poisson equation for the pressure is solved with a direct solver using Fourier transform.(2) Simulating the flame and smoke spread along the exterior wall when no balcony and water mist, analysising mechanism of the flames and hot smoke ejected from the window, obtained temperature, CO concentration in the building, and get corresponding hazard features of the fire.(3) A numerical study has been undertaken to examine the reduction of vertical flame spread due to the presence of abalcony. Paiametric studies are performed to determine the effects of balcony depth and configuration, analysing variation of temperature, velocity, CO concentration in building, find out the regularity of fire-preventing under this condition and discuss the mechanism of balcony fire-preventing. The results show that increase balcony depth can largely reduces vertical fire spread on the external wall, the best configuration of balcony for fire-preventing is open-convex balcony.(4) Numerical Study on the interaction of water mist curtain and flame ejected from Window of high-rise building. The author analyze the effect of fire-preventing role by change droplet diameter, operation pressure, angle between water curtain and vertical wall, The temperature, velocity vector distribution and the water vapor concentration in building are obtained. The results show that the droplet diameter affect fire-preventing like a parabola, the optimum operation pressure is provided, The water curtains of different dip angles have large difference in fire retardant effect for different droplet size.