Experimental modelling of buoyancy-driven flows in buildings using a fine-bubble technique

A new technique has been developed for demonstration and experimental modelling of buoyancy-driven ventilation airflows in buildings by using electrolytically generated fine hydrogen bubbles. Experiments for displacement natural ventilation in a single-zone building induced by two types of buoyancy sources, i.e. a point source and a line source, showed that the ventilation and stratification phenomena are successfully modelled by the fine-bubble technique. The experimental results for stratification interfacial positions are in good agreement with both the experimental data and theoretical predictions available in the literature. An analysis has also been carried out on similarities between the natural ventilation flows due to temperature difference and that due to concentration difference.