CFD: assessment on different bed height effect over drag model of fluidized bed

Abstract

Fluidized beds are widely used by various industries because of low pressure drop, uniform temperature distribution, high heat transfer rate and large contact area which enhances chemical reaction. It seems that the efficiency of the fluidized bed depends on the knowledge of the flow behaviour which are important for scaling, design and optimization. In modelling of gas-solid phase, drag force is one of the main mechanisms for inter-phase momentum transfer. Therefore in this study, 2D model of fluidized bed was developed to study the effect of using various drag models over different bed height of H/D ratio such as 0.5, 1 and 2. The drag correlations of Gidaspow, Wen Yu, Syamlal-O'Brien, Hill Koch Ladd (HKL) and Representative Unit Cell (RUC) are to be implemented using a multiphase Eulerian Granular Model (EGM) to simulate the interaction between phases. Simulation of the model is be conducted via commercial CFD software ANSYS FLUENT 14. The main contribution of this study is to identify the important of bed height during gasification process in order to contribute in the development of TNB Research of IGCC. From the results obtained show that EGM greatly suitable for dense particle flow. As overall, the result shows Wen Yu and Gidaspow drag model are suitable for dense fluidized bed application. While for Syamlal-O'Brien drag model is more suitable for all range of application. Finally for RUC and HKL can predict highest drag at volume fraction which is more likely occur in dense phase.