Disperse multiphase flow dense

Frequently encountered in nature and process industries, multiphase flows may comprise various states of matter, e.g., gas and solid in fluidization gas and liquid in bubble column and gas, liquid, and solid in airlift slurry bed (Mudde, 2005). In this article, the term phase in multiphase flow is related to the aggregative state of flow, which is normally far from equilibrium states. And it is different from the phase for a thermodynamic equilibrium system, where the phase is used to refer to a set of equilibrium states that can be demarcated in terms of state variables by a phase boundary on a phase diagram. As a result, it is possible to have a gas—soHd flow mixture with more than two phases, which can be classified by size, density of particles, or by the states of dispersion, e.g., poly disperse multiphase flow pCue and Fox, 2014) and dilute—dense, gas—soHd multiphase flow (Hong et al, 2012). 

It is the author s conviction that in many (turbulent) dispersed multiphase flows—except probably in very dense multiphase flow systems—the origin of mesoscale structures is in the fluid—particle interaction, with a secondary role for particle-particle interaction (coUisions, coalescence, breakup). Clustering of particles is believed to be intimately connected with the chaotic dynamics of fluid accelerations, as particles converge toward each other where and when the divergence of the acceleration field is positive (Goto... 

Langlois WE (1964) Slow Viscous Flow. Macmillan, New York Laux H (1998) Modeling of dilute and dense dispersed fluid-particle flow. Dr Ing Thesis, Norwegian University of Science and Technology, Trondheim, Norway Lawler MT, Lu P-C (1971) The role of lift in radial migration of particles in a pipe flow. In Zandi 1 (ed) Advances in Solid-Liquid Flow in Pipes and its Apphcations. Pergamon Press, Oxford, Chap 3, pp. 39-57 Lee SL (1987) Particle drag in a dilute turbulent two-phase suspension flow. Int J Multiphase Flow 13(2) 247-256... 

In the Euler—Euler approach of more dense multiphase flows, the dispersed phase may well be conceived as a second continuous phase that... 

The multi-fluid models discussed in Chap. 3 have been employed extensively describing the behavior of cold flow and reactive flow systems in multiphase reactors. However, for gas-solid fluidized bed systems, and in particular for dense systems, it has been found that the dispersed phase behavior cannot be captured without an extended description of the pressure tensor closure. The first extensions of the dilute continuum mechanical two-fluid model concept included a very rough approximation of the solid phase collisional pressure in terms of a semi-empirical correlation for the modulus of elasticity and a constant representative particle fluid viscosity. This type... 

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