Oscillating behaviour of fire-induced air flow through a ceiling vent

Oscillations of fire-induced air flow through a ceiling vent in a compartment will be studied in this paper. The equations describing the oscillations of air flow induced will be discussed first. Air flow through the vent is found to be induced by buoyancy or by pressure. A wave function was introduced as a perturbation to a control volume concerned. Oscillation growth, amplification, response and frequency will then be studied by solving these key equations under practical conditions. Useful semi-empirical formula on those parameters is derived for fire safety engineering design. The predicted results will be discussed and compared with experimental data available in the literature.