NUMERICAL INVESTIGATIONS ON A SMOKE MANAGMENT SYSTEM IN AN ADMINSTRATION BUILDING’S ATRUIM

Abstract

Smoke is considered the major reason of killing a lot of people in case of the building fire because of the reduction of visibility and asphyxiation fatalities occurred in the smoke event. The present research illustrates a numerical simulation on smoke propagation and smoke control for atrium in an administration building and investigates the effect of exhausting smoke by multi point extraction through rooftop exhaust fans on smoke layer height inside the atrium. ANSYS-FLUENT solver is used to solve two-dimensional Reynolds-averaged Navier-Stokes equations (RANS) combined with K-ε Realizable turbulence model for different study cases in an atrium. Two dimensional rectangular plan that is located at the center of atrium is simulated with the dimensions of 25m width and 20m height using T-squared fire with maximum heat release rate of 5 MW for 180 seconds. All parameters are predicted at vertical levels of 2, 13 and 17 m height from the ground floor. Results show that exhausting the smoke through rooftop exhaust fans maintain the smoke layer at higher level from the ground and has better effect on tenability conditions at human level, increasing make up air inlets levels adversely affect smoke layer height which reduce visibility at human level. Finally, the spacing between extract fans outlet is considered a major factor that should be optimized in order to avoid the plug-holing phenomena.