Visualization of counter current exchange flow using high-speed digital camera

Buoyancy-driven exchange flows of helium-air were investigated through inclined a small opening. Exchange flows may occur following a window opening as ventilation, fire in the room as well as a pipe rupture accident in a high temperature gas-cooled nuclear reactor. The experiment has carried out by a test chamber filled with helium and flow was visualized by the smoke wire method. By removing the cover plate placed on the top of the opening, the exchange flow initiated. Air enters the test chamber and the mass of the gas mixture in the test chamber increased. The flow behavior has recorded by a high-speed camera with a computer system. The image of the flow was transferred to the digital data, thus the flow velocity was measured by PTV software. The volumetric exchange flow rate was evaluated from the PTV method and mass increment method. In the case of inclination openings, the results of both methods were compared. The detected data was arranged by the densimetric Floude number of the exchange flow rate that derived from the dimensional analysis.