LAUSR

Abstract Interparticle forces (IPFs) are among the important parameters that can influence the hydrodynamics of a gas-solid fluidized bed and, hence, its overall performance. They are particularly critical at elevated temperatures, where their magnitude is typically greater than that at ambient conditions. Two simple and indirect approaches were developed in this study to quantify the magnitude of IPFs and its variation with temperature in a gas-solid fluidized bed. Quantification of thermally induced IPFs, i.e., the difference between the level of IPFs at a given temperature and that at ambient conditions, was attempted in the first approach. It was shown that the variation of IPFs with temperature is related to the difference between the experimental minimum fluidization velocity ( U mf , e x p ) and that predicted by a correlation ( U mf , p r e d ) based purely on hydrodynamic principles. The magnitude of thermally induced IPFs at a given temperature was then quantified with the help of the Ergun equation and the difference between U mf , e x p and U mf , p r e d . The second approach was developed for the quantification of absolute values of IPFs based on the difference between the loose bulk voidage ( e 0 ) and the minimum fluidization voidage ( e mf ). It was shown that the magnitude of IPFs directly affects the ratio of e mf / e 0 , which we called “dynamic Hausner ratio”. A phenomenological model was, hence, proposed where the magnitude of IPFs is expressed as a function of the dynamic Hausner ratio. The performances of these approaches were verified and qualitatively validated, while their limitations and opportunities were also discussed.