Turbulent dispersion of droplets for air flow in a pipe
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Abstract
An optical technique was used to study the dispersion of 50 μm, 90 μm and 150 μm droplets downstream of a source located in the center of a vertical pipe through which turbulent air is flowing. A turbulent dispersion coefficient, ɛP, and a mean-square of the fluctuations in the turbulent velocity, v p 2 , are determined from the change of the measured mean-square displacement of the droplets over the pipe cross section with time. The interesting aspect of the experiments is that they explored conditions where the inertia of the particles is believed to be a much more important effect than that of the “crossing of trajectories” associated with the inequality of the average velocities of the particles and the fluid.
Keywords
Average Velocity Interesting Aspect Dispersion Coefficient Optical Technique Turbulent VelocityPreview
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References
- Adam, J. R.; Cataneo, R.; Semonin, R. G. 1971: The production of equal and unequal size droplet pairs. Rev. Sci. Instrum. 42, 1847Google Scholar
- Boothroyd, R. G. 1967: Turbulence characteristics of the gaseous phase in duct flow of a suspension of fine particles. Trans. Inst. Chem. Eng. 45, T297Google Scholar
- Burchill, W. E. 1970: Statistical properties of velocity and temperature in isothermal and nonisothermal turbulent pipe flow. Ph.D. Thesis in Nucl. Eng., University of Illinois, Urbana/IL, USAGoogle Scholar
- Flint, D. L.; Kada, H.; Hanratty, T. J. 1960: Point source turbulent diffusion in a pipe. AIChE J. 6, 325Google Scholar
- Friedlander, S. K. 1957: Behavior of suspended particles in a turbulent fluid. AIChE J. 3, 381Google Scholar
- Ginsberg, T. 1970: Droplet transport in turbulent pipe flow. Ph.D. Thesis in Nucl. Eng., Pennsylvania State University, State College/PA, USAGoogle Scholar
- Groenhof, H. C. 1970: Eddy diffusion in the central region of turbulent flows in pipes and between parallel plates. Chem. Eng. Sci. 25, 1005Google Scholar
- Hinze, J. O. 1972: Progress in heat and mass transfer, vol. 6, p. 433. New York: Pergamon PressGoogle Scholar
- Laufer, J. 1954: The structure of turbulence in fully-developed pipe flow. NACA Report No. 1174Google Scholar
- Lawn, C. J. 1971: The determination of the rate of dissipation in turbulent pipe flow. J. Fluid Mech. 48, 477Google Scholar
- Lee, M. M. 1984: Droplet dispersion in vertical turbulent pipe flow. M.S. Thesis in Chem. Eng., University of Illinois, Urbana/IL, USAGoogle Scholar
- McCoy, D. D.; Hanratty, T. J. 1979: Droplet mixing and deposition in a turbulent pipe flow. In: Two-phase momentum, heat and mass transfer in chemical process and energy engineering (eds. Durst, F.; Tsiklauri, G. V.; Afgan, N. H.). Vol. 1, pp. 119–132. New York: HemisphereGoogle Scholar
- Morsi, S. A.; Alexander, A. J. 1972: An investigation of particle trajectories in two-phase flow systems. J. Fluid Mech. 55, 193PubMedGoogle Scholar
- Nir, A.; Pismen, L. M. 1979: The effect of a steady drift on the dispersion of a particle in turbulent fluid. J. Fluid Mech. 94, 369Google Scholar
- Pismen, L. M.; Nir, A. 1978: On the motion of suspended particles in stationary homogeneous turbulence. J. Fluid Mech. 84, 194Google Scholar
- Rayleigh, Lord 1879, In: Proc. London Math. Soc. 10Google Scholar
- Reeks, M. W. 1977: On the dispersion of small particles suspended in an isotropic turbulent fluid. J. Fluid Mech. 83, 529Google Scholar
- Saffman, P. G. 1965: The lift on a small sphere in a slow shear flow. J. Fluid Mech. 22, 385Google Scholar
- Sandborn, V. A. 1955: Experimental evaluation of momentum terms in turbulent pipe flow. NACA TN 3266Google Scholar
- Schneider, J. M.; Lindblad, N. R.; Hendricks, C. D.; Crowley, J. M. 1967: Stability of an electrified liquid jet. J. Appl. Phys. 38, 2599Google Scholar
- Tatterson, D. F. 1975: Rates of atomization and drop size in annular two-phase flow. Ph.D. Thesis in Chem. Eng., University of Illinois, Urbana/IL, USAGoogle Scholar
- Taylor, G. I. 1921: Diffusion by continuous movements, Proc. London Math. Soc. 151, 196Google Scholar
- Taylor, A. R.; Middleman, S. 1974: Turbulent dispersion in drag reducing fluids. AIChE J. 20, 454Google Scholar
- Towle, W. L.; Sherwood, T. K. 1939: Mass transfer in the central portion of a turbulent air stream. Ind. Chem. Eng. 31, 457Google Scholar
- Ueda, H.; Mizushina, T. 1977: Turbulence structure in the inner part of the wall region in a fully developed turbulent tube flow. 5th biennial symposium on turbulence in liquids, University of Missouri-Rolla/MO, USAGoogle Scholar
- Vames, J. S. 1982: Droplet dispersion in a turbulent pipe flow. M.S. Thesis in Chem. Eng. University of Illinois, Urbana/IL, USAGoogle Scholar
- Vames, J. S. 1985: Droplet dispersion in a turbulent pipe flow. Ph.D. Thesis in Chem. Eng. University of Illinois, Urbana/IL, USAGoogle Scholar
- Wells, M. R.; Stock, D. E. 1983: The effects of crossing trajectories on the dispersion of particles in a turbulent flow. J. Fluid Mech. 136, 31PubMedGoogle Scholar
- Yudine, M. I. 1959: Physical considerations on heavy-particle diffusion. In: Atmospheric diffusion and air pollution (Advances in Geophysics, vol. 6, p. 185). New York: Academic PressGoogle Scholar