Momentum Exchange in Solid–Fluid System Modeling with the Eulerian Multiphase Model

Abstract

This article presents the results of spouted bed grain dryer simulation tests where barley grain was the working medium and analyzes the influence of the model describing momentum exchange between components of the fluid–solid type mix on the dynamics of the fluidized bed and height of the fountain characteristic for that type of devices. The Eulerian multiphase model (EMM), in which the model describing the interphase momentum exchange was changed, while other conditions were constant, was the base of the simulation. For analysis 12 such models were used: Ergun, Wen-Yu, Nieuwland et al., Ishi-Mishima, Gibilaro et al., Syamlal-O'Brien, Gidaspow, Arastoopour et al., Ma-Ahmadi, Louge et al., Di Felice, and Andrews-O'Rourke. The computations were made using the FLUENT software package and the so-called user-defined functions. The individual sections of the article contain the mathematical description of the resistance models mentioned; verification of correctness of implementation of those models (for the models for which it was possible); presentation of the object of study (simulation tests were based on earlier made experimental tests); results of simulations for 12 resistance models and two granular viscosity models (according to Syamlal-O'Brien and Gidaspow); and considerations on selection of the resistance model in the context of a spouted bed grain dryer. Additionally, the article presents the results of simulations based on the so-called sphericity coefficient. The study aimed at verifying the possibility of applying various interaction models in modeling the dynamics of a spouted bed grain dryer.

Keywords:

• CFD
• Drag model
• Eulerian multiphase model
• Spouted bed dryer