Fire Safety Science Digital Archive

Based on the Froude modeling concept, Heskestad proposed a set of scaling relationships for the spray-plume interaction for high droplet Reynolds number conditions (ReD ? 10). The droplet Reynolds number is defined as the ratio of the product of droplet diameter and the absolute value of the droplet velocity relative to the gas velocity over the gas kinematic viscosity. Recently, Yu showed theoretically that the scaling methodology can be extended to low droplet Reynolds number conditions (ReD ?1) except for the scaling requirement for droplet size. High droplet Reynolds number conditions in general prevail in sprinkler applications and low droplet Reynolds conditions usually take place in water mist applications. To bridge the scaling gap, this paper describes a generalization of the Froude modeling approach and presents a set of general scaling relationships applicable to spray-plume interactions for all droplet Reynolds number conditions. These general scaling relationships should be experimentally validated before engineering applications.