Pressure drop and voidage measurement in solid-liquid fluidized bed: experimental, mathematical and computational study

This study is concerned with pressure drop and bed expansion behaviour of a solid liquid fluidized bed (SLFB) containing mono and binary particles of different sizes. An energy balance pressure model (EBPM) has been developed based on balancing the energy input and output rate of the mono and binary segregated SLFB. The bed voidage and pressure drop predictions of the EBPM are compared with those of Richardson-Zaki [1] and Ergun equation [2] and verified against our experimental data. EPBM well predicts (within 7% of positive deviation) in mono and binary SLFB (partially and completely segregated). However up to 30% of deviation can be seen in the completely mixed binary SLFB, because EBPM was developed considering the binary segregated SLFB. A 2D CFD model which was developed using the commercial solver ANSYS Fluent have been carried out to observe the absolute pressure distribution along the axial direction of binary SLFB. It can be seen that axial pressure distribution predictions of EBPM has a good capability in completely and partially segregated binary SLFB (compared with CFD). CFD predicted particulars information of absolute pressure in different surface location (interior surface body, velocity inlet, wall and net) of SLFB containing three different binary mixtures are also reported in this study. In addition, different averaging approaches namely serial model, packing model, property-averaging model and voidage-averaging model on bed voidge predictions are compared with present experiments and the limitations are discussed. CFD predicted bed voidage also validated against our experimental data which deviates around 6%.