Characteristics of buoyancy-driven interzonal airflow via horizontal openings

Abstract

Airflow through horizontal openings in buildings, e.g. stairwells, ventilation shafts, service shafts and chimneys, has important implications for building energy consumption, thermal comfort, contaminant control and fire safety. However, little information is available regarding the characteristics and mechanism of air exchange through horizontal openings, especially that driven by buoyancy. This paper presents a study of buoyancy-driven flow through horizontal openings using time-dependent computational fluid dynamics (CFD). The results reveal that flow patterns in the zones as well as in horizontal openings are highly transient and that the dominant mode of air exchange through openings is that of intermittent pulses. This character of instability and oscillation should be adequately represented in multizone airflow models to improve their prediction accuracy.