Experimental simulation of heat transfer augmentation by break-jets in passive containment cooling system

The studies of forced jet augmentation of natural convection heat transfer are introduced. It investigates experimentally mixed convection and heat transfer augmentation by forced jets in a large rectangular enclosure with a vertical cooling surface. The experiment is designed to measure the key parameters governing the heat transfer augmentation by a forced jet, and to investigate the effects of geometric factors, including the jet diameter, jet injection orientation, interior structures, and enclosure aspect ratio, on conditions simulating those of actual passive containment cooling systems and scales approaching those of actual containment buildings or compartments. The tests that cover a variety of injection modes will contribute to reveal the nature of mixing and stratification phenomena under accident conditions to a new generation of inherently safe reactors. With similarity considerations on governing equations, the heat transfer of mixed convection can be predicted to be controlled by Archimedes number and geometric factors. Using a combining rule for mixed convection and appropriate models of injected buoyant and impinging jets, the correlations of heat transfer augmentation are developed and tested by experimental data. The effects of jet diameter, injection orientation, interior structures, and enclosure aspect ratio on heat transfer augmentation are illustrated with analysis of experimental results. (authors)