Analysis of particle behaviors using a region-dependent method in a jetting fluidized bed

Abstract

The analysis of the flow hydrodynamics in jetting fluidized beds is of considerable significance as it is widely applied in pharmaceutical, food, chemical, and petrochemical industries. In this study, an improved sub grid scale (SGS) model in the large eddy simulation (LES) method has been used based on a discrete hard sphere particle model in a jetting fluidized bed. The comparison of simulation results with experimental data shows that the improved SGS method, with a mutative Smagorinsky constant SGS approach, results in a better agreement than when using an invariant constant. Furthermore the particle behavior was analyzed by a region-dependent analysis method to obtain the spatial relationship of the particle behavior. The tendency of macro particle behavior is quite different from that at the micro level, which means that the fluctuation in the bed is not related to the overall particle movement. The particle macro characteristics can be affected by multiple factors such as the type of gas in the jet, the type of particles and the bubbles in the bed. The granular temperature distribution, which is related to the micro turbulent movement, presents strong anisotropic features, and specific rules of bubble and particle behavior are deduced. The region-dependent analysis method is also discussed in this work.