Numerical investigation on the air inflow rate for fuel-controlled compartment fire under ambient wind condition

Abstract

So far, extensive researches have been conducted on compartment fire characteristics in no wind conditions. However, there are still few researches focusing on the air flow rate through opening of compartment under influence of ambient wind, noting that the air inflow rate is related to fire growth, indoor temperature, heat convection between indoor and outdoor environments, and the corresponding thermal impact to adjacent rooms. This paper investigated the air flow rate for fuel-controlled compartment fire under the ambient wind through numerical simulation. Temperature inside compartment, gas velocity along the opening vertical centerline and the air inflow rate were obtained for various fuel supply rates and wind speeds. Results show that: (1) The air inflow rate increases as the opening size increases. (2) The air inflow rate increases as the fire heat release rate increases, and the increasing rate decreases for higher fire heat release rates. (3) The air inflow rate increases as wind speed increases. Influence mechanism of ambient wind was revealed through pressure analysis, including the static pressure and dynamic pressure. A Froude number was proposed to describe the wind pressure effect, then the air inflow rate model was established, which has good consistency with the simulated data.