CFD Modeling of gas-solid

Ranade, V.V. (1999), Modelling of gas-solid flows in FCC riser reactor fully developed flow, 2nd International Conference on CFD, Melbourne. 

The EMMS model was proposed for the time-mean behavior of fluidized beds on the reactor scale. A more extensive application of the EMMS model to gas-solid flow is through its coupling with the two-fluid CFD approaches, which brings about an EMMS-based multi-scale CFD framework for gas—solid flow. For this purpose, Yang et al. (2003) introduced an acceleration, a, into the EMMS model to account for the... 

Rampure, M.R., Buwa, V.V., and Ranade, V.V. (2003), Modelling of gas-liquid/gas-liquid-solid flows in bubble columns Experiments and CFD simulations, The Canadian Journal of Chemical Engineering, 81 692-706. 

Jia X, Wen J, Wang X, Feng W, Jiang Y. CFD modelling of phenol biodegradation by immobilized Candida tropicalis in a gas-liquid-solid three-phase bubble column. Chem. Eng. J. 2010 157 451-465. 

Prediction of gas solid flow fields, in processes such as pneumatic transport lines, risers, fluidised-bed reactors, hoppers and precipitators are crucial to the operation of most process plants. Up to now, the inability to accurately model these interactions has limited the role that simulation could play in improving operations. In recent years, CFD software developers have focused on this area to develop new modelling methods that can simulate gas-liquid-solid flows to a much higher level of reliability. As a result, process industry... 

Wang W, Li J Simulation of gas-solid two-phase flow by a multi-scale CFD approach— extension of the EMMS model to the sub-grid level, Chem Eng Sci 62 208—231, 2007. Wang H, Menon N Heating mechanism affects equipartition in a binary granular system, Phys Rev Lett 100 158001, 2008. 

In the Euler-Euler models, i.e., the TFMs, it is assumed that both the gas and the solid phase are interpenetrating continua. This continuous approach is especially useful and computationally cost-effective when the volume fractions of the phases are comparable, or when the interaction within and between the phases plays a significant role in determining the hydrodynamics of the system. As discussed before, it is relatively straightforward to model the gas phase, for instance by the use of well-established CFD techniques. The challenge is to establish an accurate hydrodynamic description of the particulate phase. 

Our discussion of multiphase CFD models has thus far focused on describing the mass and momentum balances for each phase. In applications to chemical reactors, we will frequently need to include chemical species and enthalpy balances. As mentioned previously, the multifluid models do not resolve the interfaces between phases and models based on correlations will be needed to close the interphase mass- and heat-transfer terms. To keep the notation simple, we will consider only a two-phase gas-solid system with ag + as = 1. If we denote the mass fractions of Nsp chemical species in each phase by Yga and Ysa, respectively, we can write the species balance equations as... 

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