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The diffusion of conserved and reactive scalars behind line sources in homogeneous turbulence

Published online by Cambridge University Press:  26 April 2006

J. D. Li
Affiliation:
Department of Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia Present address: Department of Mechanical Engineering, Victoria University of Technology, PO Box 14428, MMC, Melbourne, Victoria 3000, Australia.
R. W. Bilger
Affiliation:
Department of Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia

Abstract

Experimental results for the statistics of turbulent reactive plumes behind line sources are given. The results are obtained with sufficient spatial and time scale resolution and cover the near and far fields. The results for the conserved scalar, which is constructed from the two reactive scalars, are consistent with those measured in passive thermal plumes. The results for the reactive scalars show that within the experimental range, turbulent mixing is the dominant contributor to the spread rate of the plume and the contribution from chemical reaction is small. However it is found that chemical reaction has a large effect on the decay of the plume reactant concentration and this effect depends on the stoichiometric mixture fraction. The gradient model for turbulent diffusion and the conventional model for the dissipation time scale of scalar variance have been tested and it is found that they are satisfactory in the far field of the plume. However large errors can result in the near field. Also it is found that the turbulent diffusitivities derived from the conserved and reactive scalars are about the same. Various models for the mean chemical reaction rate have been checked and it is concluded that an interpolation between the frozen and equilibrium limits for the covariance of the two reactive scalars will model the mean chemical reaction rate reasonably well.

Type
Research Article
Copyright
© 1996 Cambridge University Press

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References

Anand, M. S. & Pope, S. B. 1985 Diffusion behind a line source in grid turbulence. In Turbulent Shear Flows 4 (ed. L. J. S. Bradbury, F Durst, B. E. Launder, F. W. Schmidt & T. H. Whitelaw), pp. 4661. Springer.
Bilger, R. W. 1989 Turbulent diffusion flames. Ann. Rev. Fluid Mech. 21, 101135.Google Scholar
Bilger, R. W. 1993 Conditional moment closure for turbulent reacting flow. Phys. Fluids A 5, 436444.Google Scholar
Bilger, R. W., Saetran, L. R. & Krishnamoorthy, L. V. 1991 Reaction in a scalar mixing layer. J. Fluid Mech. 233 211242.Google Scholar
Brown, R. J. & Bilger, R. W. 1996 An experimental study of a reactive plume in grid turbulence. J. Fluid Mech. 312, 373407.Google Scholar
Chameides, W. L. & Stedman, D. H. 1977 Tropospheric ozone: coupling transport and photo chemistry. J. Geophys. Res. 82, 17871794.Google Scholar
Chatwin, P. C. & Sullivan, P. J. 1990 A simple and unifying physical interpretation of scalar fluctuation measurements from many turbulent shear flows. J. Fluid Mech. 212, 533556.Google Scholar
Corrsin, S. 1974 Limitations of gradient transport models in turbulence. Adv. Geophys. 18A, 2560.Google Scholar
Deardorff, J. W. 1978 Closure of second- and third-moment rate equation for diffusion on homogeneous turbulence. Phys. Fluids 21, 525530.Google Scholar
Deardorff, J. W. & Wills, G. E. 1975 A parameterization of diffusion into the mixing layer. J. Appl. Met. 14, 14511458.Google Scholar
Durbin, P. A. 1980 A stochastic model of two-particle dispersion and concentration fluctuations in homogeneous turbulence. J. Fluid Mech. 100, 279302.Google Scholar
Fackrell, J. E. & Robins, A. G. 1982 Concentration fluctuations and fluxes in plume from point sources in a turbulent boundary layer. J. Fluid Mech. 117, 126.Google Scholar
Jayesh Warhaft, Z. 1992 Probability distribution, conditional dissipation and transport of passive temperature fluctuations in grid generated turbulence. Phys. Fluids A 4, 22922307.Google Scholar
Komori, S., Hunt, J. C. R., Kanzaki, T. & Murakami, Y. 1991 The effects of turbulent mixing on the correlation between two species and on concentration fluctuations in non-premixed reacting flows. J. Fluid Mech. 228 629659.Google Scholar
Koochesfahani, M. M. & Dimotakis P. E. 1986 Mixing and chemical reactions in a turbulent liquid mixing layer. J. Fluid Mech. 170, 83112.Google Scholar
Li, J. D. & Bilger, R. W. 1993 Measurement and prediction of the conditional variance in a turbulent reactive scalar-mixing layer. Phys. Fluids A 5, 32553264.Google Scholar
Li, J. D. & Bilger, R. W. 1994 A simple theory of conditional mean velocity in turbulent scalar-mixing layer. Phys. Fluids A 6, 605610.Google Scholar
Li, J. D., Brown, R. J. & Bilger, R. W. 1992 Experimental study of scalar mixing layer using reactive and passive scalars. In Proc. Eleventh Australasian Fluid Mechanics Conf., University of Tasmania (ed. M. R. Davis & G. J. Walker), pp. 159162.
Mole, N. & Clarke, E. D. 1995 Relationships between higher moments of concentration and of dose in turbulent dispersion. Boundary-Layer Met. 73, 3552.Google Scholar
Mole, N. & Jones, C. D. 1994 Concentration fluctuation data from dispersion experiments carried out in stable and unstable conditions. Boundary-Layer Met. 67, 4174.Google Scholar
Monin, A. S. & Yaglom, A. M. 1975 Statistical Fluid Mechanics, vol. 2. MIT Press.
Mudford, N. R. & Bilger, R. W. 1983 A facility for the study of non-equilibrium chemistry in an isothermal turbulent flow. In Proc. Eighth Australasian Fluid Mechanics Conf., University of Newcastle.
Mudford, N. R. & Bilger, R. W. 1985 Examination of closure models for mean chemical reaction using experimental data for an isothermal turbulent reacting flow In 20th Symp. (Intl) on Combustion, pp. 387394. The Combustion Institute.
Post, K. & Kewley, D. J. 1978 Calibration of an ozone calibration reference instrument. Clean Air 12, 25.Google Scholar
Roshko, A. 1954 On the development of turbulent wakes from vortex streets. Rep. 1191. California Institute of Technology.
Sawford, B. L. 1992 Spatial structure of concentration moments in homogeneous turbulence. In 10th Symp. on Turbulent and Diffusion. Portland, Oregon, pp. 180183. AMS (Boston).
Sawford, B. L. & Hunt, J. C. R. 1986 Effects of turbulence structure, molecular diffusion and source size on scalar fluctuation in homogeneous turbulence. J. Fluid Mech. 165, 373400.Google Scholar
Sawford, B. L. & Sullivan, P. J. 1995 A simple representation of a developing contaminant concentration field. J. Fluid Mech. 289, 141157.Google Scholar
Stapountzis, H. & Britter, R. E. 1989 Turbulent diffusion behind a heated line source in a nearly homogeneous turbulent shear flow. In Turbulent Shear Flow 6 (ed. F. J. Durst, B. E. Launder, F. W. Schmidt & J. H. Whitelaw), pp. 97108. Springer.
Stapountzis, H., Sawford, B. L., Hunt, J. C. R. & Britter, R. E. 1986 Structure of the temperature field downstream of a line source in grid turbulence. J. Fluid Mech. 165, 401424.Google Scholar
Sykes, R. I., Lewellen, W. S. & Parker, S. F. 1984 A turbulent-transport model for concentration fluctuations and fluxes. J. Fluid Mech. 139, 193218.Google Scholar
Thomson, D. J. 1990 A stochastic model for the motion of particle pairs in isotropic high-Reynolds-number turbulence, and its application to the problem of concentration variance. J. Fluid. Mech. 210, 113153.Google Scholar
Toor, H. C. 1969 Turbulent mixing of two species with and without chemical reaction. Indust. Engng Chem. Fundam. 8, 655659.Google Scholar
Toor, H. C. 1993 Effect of chemical reactions on turbulent diffusitivity AIChE J. 39, 16031610.Google Scholar
Townsend, A. A. 1954 The diffusion behind a line source in homogeneous turbulence. Proc. R. Soc. Lond. A 224, 487512.Google Scholar
Uberoi, M. S. & Corrsin, S. 1952 Diffusion of heat from a line source in isotropic turbulence. National Advisory Committee for Aeronautics. Tech. Note 2710.
Veeravalli, S. & Warhaft, Z. 1989 The shearless turbulent mixing layer. J. Fluid Mech. 207, 191229.Google Scholar
Warhaft, Z. 1984 The interference of thermal fields from line sources in grid turbulence. J. Fluid Mech. 144, 363387.Google Scholar
Warhaft, Z. & Lumley, J. L. 1978 An experimental study of the decay of temperature fluctuations in grid turbulence. J. Fluid Mech. 88, 659684.Google Scholar