Entrainment by two-dimensional spill plumes

Abstract A simple model is proposed for estimating the mass entrainment into two-dimensional (2D) free plumes. The model rests on the assumption that the entrainment into the curved section of a spilling plume is approximately equal to the entrainment into a vertical free plume rising through the same height. The model is shown to be in good agreement with measurements in several small-scale models. The measured entrainment coefficient for the 2D plumes in the scale model studies, which had been determined from measurements of entrainment into the vertical portion of those plumes, was found to be around C m =0·44, slightly below recently proposed values for unbounded 2D plumes. It is suggested that the observed deviations from the proposed model of measurements in two small-scale models of atria might have been caused by the relatively small size or shape of those atria.

[1]  P. H. Thomas,et al.  On the upward movement of smoke and related shopping mall problems , 1987 .

[2]  M. S. Chandrasekhara,et al.  Measurements in Vertical Plane Turbulent Plumes , 1989 .

[3]  Geoffrey Ingram Taylor,et al.  Turbulent gravitational convection from maintained and instantaneous sources , 1956, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[4]  Edward E. Zukoski,et al.  Entrainment in the Near and Far Field of Fire Plumes , 1984 .

[5]  P. L. Hinkley.  Rates of 'production' of hot gases in roof venting experiments , 1986 .

[6]  Matthew Law.  A note on smoke plumes from fires in multi-level shopping malls , 1986 .

[7]  M. Delichatsios,et al.  Strong Turbulent Buoyant Plumes. I. Similarity , 1980 .

[8]  H. W. Emmons,et al.  A study of natural convection above a line fire , 1961, Journal of Fluid Mechanics.

[9]  Wolfgang Rodi,et al.  Vertical turbulent buoyant jets : a review of experimental data , 1980 .

[10]  H. P. Morgan.  The horizontal flow of buoyant gases toward an opening , 1986 .

[11]  H. P. Morgan,et al.  On power laws for describing the mass flux in the near field of fires , 1996 .

[12]  Margaret Law.  Measurements of balcony smoke flow , 1995 .

[13]  Gunnar Heskestad,et al.  Engineering relations for fire plumes , 1984 .

[14]  Hunter Rouse,et al.  Gravitational Convection from a Boundary Source , 1952 .

[15]  Gunnar Heskestad,et al.  Virtual origins of fire plumes , 1983 .

[16]  P. H. Thomas.  Discussion of 'measurements of balcony smoke flow', [fire safety j., 24 (1995) 189-195 , 1995 .