A review of instability criteria of smoke layers under sprinkler spray

Three different criteria have been developed to determine the smoke layer behavior under sprinkler spray and these are known as the Bullen criterion, the Zhang criterion and the Li criterion. A review is carried out theoretically and experimentally to validate these criteria. The experimental results have shown that the values of all three criteria are less than unity when a smoke layer is stable under sprinkler spray, but only the Li criterion becomes greater than unity after smoke logging occurs. When the three criteria are physically compared the results show that the spatial distribution has a significant impact on the smoke layer behavior and also determines the shape of the smoke logging plume