Numerical analysis of interphase heat and mass transfer of cluster in a circulating fluidized bed

Interphase heat and mass transfer characteristics of a naphthalene particle cluster in a circulating fluidized riser are numerically analyzed using a three-dimensional CFD model. Heat and mass transfer characteristics of gas over an in-line array of three naphthalene particles and an isolated naphthalene particle are analyzed. Distributions of gas concentration, temperature and velocity are obtained. The heat and mass transfer rates of gas-to-cluster increase with the increase of the cluster porosity and Reynolds number. Present simulations indicate that the small cluster gives higher heat and mass transfer coefficients than those of the large cluster. The heat and mass transfer rates of individual particles in the cluster are lower than that of an isolated particle and particles in an in-line array under a given cluster porosity.

Graphical abstractThe Nusselt and Sherwood numbers are computed as a function of cluster porosity. Both Nusselt and Sherwood numbers increase with the increase of cluster porosity. Heat and mass fluxes of an individual particle in the cluster are lower than that of an isolated particle and particles in an in-line array. The smaller cluster gives higher heat and mass transfer rates than those of the larger cluster at the given cluster porosity. The heat and mass transfer of gas-to-particle in the cluster are affected by its neighboring particles as well as interstitial flow distribution.Figure optionsDownload full-size imageDownload as PowerPoint slide