Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-26T21:38:46.840Z Has data issue: false hasContentIssue false

Phase Doppler anemometry measurements and analysis of turbulence modulation in dilute gas–solid two-phase shear flows

Published online by Cambridge University Press:  27 September 2010

FEI LI
Affiliation:
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
HAIYING QI*
Affiliation:
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
CHANGFU YOU
Affiliation:
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
*
Email address for correspondence: hyqi@mail.tsinghua.edu.cn

Abstract

Flow velocities of a dilute gas–solid two-phase flow in a vertical sudden expansion were measured using phase Doppler anemometry to study the behaviour of the turbulence modulation for the stronger shear for various particle mass loadings, inlet Reynolds numbers and particle diameters. The measurements show that the particles changed the gas turbulence by elongation of the entire gas flow field in the downstream direction, which displaced the axial profile of the section-averaged fluctuation velocity in comparison with that of the single-phase flow, and by either the particle inertia reducing the local turbulence or the wake eddy effects enhancing the turbulence. Both mechanisms resulted in an apparent turbulence modulation, which has not been referred to in the related literature, and have led to an ambiguous understanding of turbulence modulation. The elongation and inlet effects should be eliminated to estimate whether the gas turbulence was really modified. The linear relationship between the gas mean velocity gradient and the root-mean-square fluctuation velocity, which was found to be similar to that in single-phase flows, gradually disappeared as the flow developed and the shear intensity reduced. The linear relationship also varied with different conditions. Specifically, the turbulence modulation was enhanced by higher particle mass loadings and the linear relationship disappeared with increasing particle mass loading. This linearity can perhaps be regarded as a criterion for determining the effect of stronger turbulence modulation.

Type
Papers
Copyright
Copyright © Cambridge University Press 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Boivin, M., Simonin, O. & Squires, K. D. 1998 Direct numerical simulation of turbulence modulation by particles in isotropic turbulence. J. Fluid Mech. 375, 235263.CrossRefGoogle Scholar
Crowe, C. T. 2000 On models for turbulence modulation in fluid–particle flows. Intl J. Multiphase Flow 26, 719727.CrossRefGoogle Scholar
DANTEC 1994 PDA Installation and User's Guide.Google Scholar
Elghobashi, S. & Truesdell, G. C. 1993 On the two-way interaction between homogeneous turbulence and dispersed solid particles. I: Turbulence modification. Phys. Fluids A 5, 17901801.CrossRefGoogle Scholar
Fessler, J. R. & Eaton, J. K. 1999 Turbulence modification by particles in a backward-facing step flow. J. Fluid Mech. 394, 97117.CrossRefGoogle Scholar
Gore, R. A. & Crowe, C. T. 1989 Effect of particle size on modulating turbulent intensity. Intl J. Multiphase Flow 15, 279285.CrossRefGoogle Scholar
Hadinoto, K., Jones, E. N., Yurteri, C. & Curtis, J. S. 2005 Reynolds number dependence of gas-phase turbulence in gas–particle flows. Intl J. Multiphase Flow 31, 416434.CrossRefGoogle Scholar
Hetsroni, G. 1989 Particle–turbulence interaction. Intl J. Multiphase Flow 15, 735746.CrossRefGoogle Scholar
Hetsroni, G. & Sokolov, M. 1971 Distribution of mass, velocity, and intensity of turbulence in a two-phase turbulent jet. J. Appl. Mech. 38, 315327.CrossRefGoogle Scholar
Hinze, J. O. 1975 Turbulence. McGraw-Hill.Google Scholar
Kussin, J. & Sommerfeld, M. 2002 Experimental studies on particle behaviour and turbulence modification in horizontal channel flow with different wall roughness. Exp. Fluids 33, 143159.CrossRefGoogle Scholar
Levy, Y. & Lockwood, F. C. 1981 Velocity measurements in a particle laden turbulent free jet. Combust. Flame 40, 333339.CrossRefGoogle Scholar
Li, F., Qi, H. Y. & You, C. F. 2007 Analysis of turbulence modulation in a sudden-expansion flow laden with fine particles. In Multiphase Flow: The Ultimate Measurement Challenge (ed. Cai, X., Wu, Y., Huang, Z., Wang, S. & Wang, M.), vol. 914, pp. 6979. American Institute of Physics.Google Scholar
Li, F., Qi, H. Y., You, C. F. & Bao, Y. J. 2006 Study on turbulence modulation of gas–solid two-phase flow in a sudden-expansion tube. J. Engng Thermophys. 27, 201204.Google Scholar
L'vov, V. S., Ooms, G. & Pomyalov, A. 2003 Effect of particle inertia on turbulence in a suspension. Phys. Rev. E 67, 046314.Google Scholar
Modarress, D., Tan, H. & Elghobashi, S. 1984 Two-component LDA measurement in a two-phase turbulent jet. AIAA J. 22, 624630.CrossRefGoogle Scholar
Ooms, G., Poelma, C., Poesio, P., Pourquie, M. B. M. & Westerweel, J. 2008 Verification of a model to predict the influence of particle inertia and gravity on a decaying turbulent particle-laden flow. Intl J. Multiphase Flow 34, 2941.CrossRefGoogle Scholar
Poelma, C., Westerweel, J. & Ooms, G. 2007 Particle–fluid interactions in grid-generated turbulence. J. Fluid Mech. 589, 315351.CrossRefGoogle Scholar
Prandtl, L. 1952 Essentials of Fluid Dynamics. Hafner.Google Scholar
Qi, H. 1997 Euler/Euler-simulation der Fluiddynamik Zirkulierender Wirbelschichten. Verlag Mainz, Wissenschaftsverlag.Google Scholar
Sheen, H. J., Jou, B. H. & Lee, Y. T. 1994 Effect of particle size on a two-phase turbulent jet. Exp. Therm. Fluid Sci. 8, 315327.CrossRefGoogle Scholar
Sundaram, S. & Collins, L. R. 1999 A numerical study of the modulation of isotropic turbulence by suspended particles. J. Fluid Mech. 379, 105143.CrossRefGoogle Scholar
Tashiro, H., Watanabe, E., Shinano, H., Funatsu, K. & Tomita, Y. 2001 Effect of mixing gas–fine particle suspension flow with small amount of coarse ones in a horizontal pipe. Intl J. Multiphase Flow 27, 20012013.CrossRefGoogle Scholar
Tsuji, Y. & Morikawa, Y. 1982 LDV measurements of an air–solid two-phase flow in a horizontal pipe. J. Fluid Mech. 120, 385409.CrossRefGoogle Scholar
Tsuji, Y., Morikawa, Y. & Shiomi, H. 1984 LDV measurements of an air–solid two-phase flow in a vertical pipe. J. Fluid Mech. 139, 417434.CrossRefGoogle Scholar
Tsuji, Y., Morikawa, Y., Tanaka, T., Karimine, K. & Nishida, S. 1988 Measurement of an axisymmetric jet laden with coarse particles. Intl J. Mutiph. Flow 14, 565574.CrossRefGoogle Scholar
Varaksin, Yu, , A., Kurosaki, Y., Satoh, I., Polezhaev, Yu, , V. & Polyakov, A. F. 1998 Experimental study of the direct influence of the small particles on the carrier air turbulence intensity for pipe flow. In Third International Conference on Multiphase Flow (On CD-ROM).Google Scholar
Yan, X. F. & Wang, X. L. 2007 Effect of different material particle on the modulation of two-phase turbulent jets. J. Tsinghua Univ. (Sci. Technol.) 47, 13751379.Google Scholar
Yarin, L. P. & Hetsroni, G. 1994 Turbulence intensity in dilute two-phase flows: the particles–turbulence interaction in dilute two-phase flow. Intl J. Multiphase Flow 20, 2744.CrossRefGoogle Scholar
Yu, Y. 2004 Studies on gas turbulence modification in gas-particle flows and a dense two-phase turbulence model. PhD thesis, Tsinghua University, Beijing.Google Scholar
Yuan, Z. & Michaelides, E. E. 1992 Turbulence modulation in particulate flows: a theoretical approach. Intl J. Multiphase Flow 18, 779785.CrossRefGoogle Scholar
Zhang, Z. S., Cui, G. X. & Xu, C. X. 2005 Theory and Modeling of Turbulence. Tsinghua University Press.Google Scholar