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Author
Delichatsios, M. A. | Orloff, L.
Title
Entrainment Measurements in Turbulent Buoyant Jet Flames and Implications for Modeling.
Coporate
Factory Mutual Research Corp., Norwood, MA
Sponsor
National Bureau of Standards, Gaithersburg, MD
Report
FMRC J.I. 0K0J2.BU; RC84-BT-6, November 1984,
Book or Conf
Combustion Institute, Symposium (International) on Combustion, 20th. August 12-17, 1984, Combustion Institute, Pittsburgh, PA, Ann Arbor, MI, 367-375 p., 1984
Keywords
turbulent jet flames | nozzles | fire plumes | flame research | entrainment
Abstract
Air entrainment rates were measured along turbulent buoyant jet flames having heat release rates up to 45 kW and nozzle diameters 12 mm and 23 mm. We used the Ricou-Spalding measurement technique which involves supplying just enough ambient air to an enclosure around the flame to produce zero pressure drop across an exit orifice plate. The experimental enclosure, the orifice plate and the pressure lines were water-cooled because of the large radiative output from the fires. The entrainment rates at various positions in the turbulent flame for the larger nozzle (23 mm dia) were independent of the total heat release rate (20 kW, 31 kW and 45 kW) and increased with the 5/2 power o the distance from the nozle exit. Similar behavior was observed for the smaller nozzle but with a virtual origin some distance above the nozzle exit. Our results indicate that existing integral models of turbulent burning fail to account for the nonequilibrium nature of turbulence in fire plumes.