Bubbling Bed Reactor Simulations Using Two-Fluid Models

5 Bubbling Bed Reactor Simulations Using Two-Fluid Models 

The bubbling bed reactor flow investigation performed by Lindborg [91] and Lindborg et al [92] is assessed in this section. 

Srivastava and Sundaresan [127] calculated the total stress as a linear sum of the kinetic, collisional, and frictional stress components, where each of the contributions are evaluated as if they were alone. The extended particle pressure and viscosity properties are calculated as  

This model is supposed to capture the two extreme limits of granular flow, which are designating the rapid shear and quasi-static flow regimes. In the rapid shear flow regime the kinetic stress component dominates, whereas in the quasi-static flow regime the friction stress component dominates [127]. 

The parameters adopted in the work of Lindborg et al [92] were taken from Ocone et al [105]. Johnson et al [70] used a similar set of parameters. Both sets of parameter values are listed in table 10.4. 

In the literature numerous two-fluid models of different complexity have been proposed to predict the fluidized bed reactor cold flow and reactive flow behaviors. Four decades ago emphasis was placed on the modeling of the velocity fluctuation co-variance terms in the dispersed particle fluid phase momentum equations. The early one-dimensional models were normally closed by an elasticity modulus parameterization for the particle phase collisional pressure and a constant viscosity parameter for the corresponding shear stresses. Later, with the improved computer memory and speed capacities, multi-dimensional flow models and more advanced model closures were developed based on the kinetic theory of granular flow (KTGF). Moreover, the 

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