Evaluation of heat and mass transfer through a large horizontal opening.

The work was concerned with measuring natural convection through a large horizontal opening between two rooms in a building. Airflow rates between the two rooms were measured using a tracer-gas decay technique. Room 1 was heated to various temperatures in the range l8°C to 33°C using thermostatically-controlled heaters. Room 2 was unheated. A multi-point sampling unit was used to collect tracer-gas samples from each room. The concentration of SF6 tracer was measured using an infra-red gas analyser. The heat and mass flow rates between the two rooms were calculated from the tracer-gas concentrations and temperature differences. The coefficient of discharge of the opening was found to be function of the temperature difference between the two rooms.