- Author
- Cooper, L. Y.
- Title
- Ceiling Jet Properties and Wall Heat Transfer in Compartment Fires Near Regions of Ceiling Jet-Wall Impingement.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
- Report
- NBSIR 86-3307, January 1986, 33 p.
- Distribution
- Available from National Technical Information Service
- Keywords
- ceilings | compartment fires | convective heat transfer | enclosure fires | fire plumes | fire modeling | heat transfer | room fires | walls
- Abstract
- The problem of heat transfer to walls from fire plume-driven ceiling jets during compartment fires is introduced. An analogy is drawn between the flow dynamics and heat transfer at ceiling jet-wall impingement and at the line impingement of a wall and a two-dimensional, plane, free jet. Using the analogy, the literature on plane, free jet flows and corresponding wall stagnation heat transfer rates leads to readily useable estimates for the heat transfer from, and the mass, momentum, and enthalpy fluxes of the turned compartment fire ceiling jet as it begins its initial descent as a negatively buoyant flow along the compartment walls. Availble data from a reduced-scale experiment provides some limited verification of the heat transfer estimate. Depending on the proximity of a wall to the point of plume-ceiling impingement, the estimates indicate that for "typical" full-scale compartment fires with energy release rates in the range 200-2000kW and fire-to-ceiling distances of 2-3m, the rate of het transfer to walls can be enhanced by a factor of 1-2.5 over the heat transfer to ceilings immediately upstream of ceiling jet-wall impingement.