Numerical computation of turbulent gas-particle flow in a 90 degree bend: comparison of two particle modelling approaches

Abstract

A numerical study into the physical characteristics of dilute gas-particle flows over a square-sectioned $90^\circ$~bend is reported. Two approaches, namely the Lagrangian particle tracking model and Eulerian two fluid model are employed to predict the gas-particle flows. Renormalization Group based $k$-$\epsilon$ model is used as the turbulent closure for both the approaches; however, for the Eulerian model, additional transport equations are solved to account for the combined gas-particle interactions and the turbulence kinetic energy of the particulate phase. In comparison to both Eulerian-Eulerian and Eulerian-Lagrangian approaches the former was found to yield closer agreement with the measured values. The Eulerian-Lagrangian approach obtains finer details of the behaviour of particles, while Eulerian-Eulerian model can be used for industrial scale problems. All the simulated results are compared against the experimental finding of Kliafas and Holt (1987). References J. A. C. Humphrey, J. H. Whitelaw, and G. Yee. Turbulent flow in a square duct with strong curvature. J. Fluid Mech., 103:443--463, 1981. doi:10.1017/S0022112081001419. Y. Kliafas and M. Holt. Ldv measurements of a turbulent air-solid two-phase flow in a 90 degree bend. Exp. Fluids, 5:73--85, 1987. doi:10.1007/BF00776177. J. D. Kulick, J. R. Fessler, and J. K. Eaton. Particle response and turbulence modification in fully developed channel flow. J. Fluid Mech., 277:109--134, 1994. doi:10.1017/S0022112094002703. Z. F. Tian, J. Y. Tu, and G. H Yeoh. Numerical simulation and validation of dilute gas- particle flow over a backward-facing step. Aerosol Sci. Technol., 39:319--332, 2005. doi:10.1080/027868290930961. J. Y Tu. Computational of turbulent two-phase flow on overlapped grids. Numer. Heat Transfer Part B Fundam, 32:175?195, 1997. doi:10.1080/10407799708915004. J. Y. Tu and C. A. J. Fletcher. An improved model for particulate turbulence modulation in confined two-phase flows. Int. Commun. Heat Mass Transfer, 21(6):775--783, 1994. doi:10.1016/0735-1933(94)90031-0. J. Y. Tu and C. A. J. Fletcher. Numerical computation of turbulent gas-solid particle flow in a 90 degree bend. AIChE Journal, 41(10):2187--2197, 1995. doi:10.1002/aic.690411003. A. Adeniji-Fashola and C. P. Chen. Modelling of confined turbulent fluid-particle flows using eulerian and lagrangian schemes. Int. J. Heat Mass Transfer, 3(4):691--701, 1990. doi:10.1016/S0307-904X(98)00007-9. F. Durst, D. Milojevic, and B. Schonung. Eulerian and lagrangian predictions of particulate two-phase flows :a numerical study. Appl. Math. Model, 8(2):101--115, 1984. doi:10.1016/0307-904X(84)90062-3. J. R. Fessler and J. K. Eaton. Particle response in a planar sudden expansion flow. Expl Thermal and Fluid Sci, 15:413--423, 1997. doi:10.1016/S0894-1777(97)00010-1. J. R. Fessler and J. K. Eaton. Turbulence modification by particles in a backward-facing step flow. J. Fluid Mech, 394:97--117, 1999. http://journals.cambridge.org/action/displayAbstract?aid=15369.