CFD-DEM Simulation of Minimum Fluidisation Velocity in Two Phase Medium

H Khawaja


In this work, CFD-DEM (computational fluid dynamics - discrete element method) has been used to model the 2 phase flow composed of solid particle and gas in the fluidised bed. This technique uses the Eulerian and the Langrangian methods to solve fluid and particles respectively. Each particle is treated as a discrete entity whose motion is governed by Newton's laws of motion. The particle-particle and particle-wall interaction is modelled using the classical contact mechanics. The particles motion is coupled with the volume averaged equations of the fluid dynamics using drag law.

In fluidised bed, particles start experiencing drag once the fluid is passing through. The solid particles response to it once drag experienced is just equal to the weight of the particles. At this moment pressure drop across the bed is just equal to the weight of particles divide by the cross-section area. This is the first regime of fluidization, also referred as ‘the regime of minimum fluidization’.

In this study, phenomenon of minimum fluidization is studied using CFD-DEM simulation with 4 different sizes of particles 0.15 mm, 0.3 mm, 0.6 mm, and 1.2 mm diameters. The results are presented in the form of pressure drop across the bed with the fluid superficial velocity. The achieved results are found in good agreement with the experimental and theoretical data available in literature.

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Anderson J.D. (1995). Computational fluid dynamics, McGraw-Hill, 237-239.

Anderson T.B, Jackson R. (1967). Industrial and Engineering Chemistry Fundamentals, 6, 4, 527-539. CrossRef

Beetstra R., Van der Hoef, M.A., Kuipers J.A.M. (2007). Numerical study of segregation using a new drag force correlation for polydisperse systems derived from Lattice Boltzmann simulations. Chemical Engineering Science, 62, 246-255. CrossRef

Chitester D. C., Kornosky M. R., Fan L. S. and Danko J. P. (1984) Characteristics of fluidization at high pressure, Chemical Engineering Science, 39, 253-261. CrossRef

Courant R, Friedrichs K, Lewy H. (1967) On the partial difference equations of mathematical physics, IBM Journal, 215-234.

Cundall P, & Strack O. (1979) A discrete element model for granular assemblies, Geotechnique, 29, 47. CrossRef

Hairer, Nørsett, Wanner, Gerhard (1993) Solving ordinary differential equations I: Nonstiff problems, Springer Verlag.

Hertz H. (1882) Uber die Beruhrang fester elastischer Korper (On the contact of elastic solids), Journal der rennin und angewandeten Mathematik. 92, S. 156-171.

Kunii D. and Levenspiel O. (1991). Fluidization Engineering. Butterworth-Heinemann, Stoneham, USA

Lee S. and Lee L. (2005) Encyclopaedia of Chemical Processing, CRC Press, Boca Raton, Florida

Mindlin R. D. & Deresiewicz H. (1953) Elastic Spheres in Contact under Varying Oblique Forces, Journal of Applied Mechanics, 20, 327.

Tsuji Y, Kawaguchi T, & Tanaka T. (1992) Discrete particle simulation of two-dimensional fluidised bed, Powder Technology, 77, 79-87. CrossRef

Wen C. Y. and Yu Y. H. (1966) A generalized method for predicting the minimum fluidization velocity, AIChE Journal, 12, 610-612. CrossRef


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