Hydrodynamics modeling of an LSCFB riser using ANFIS methodology: Effects of particle shape and size

ANFIS modeling approaches is applied to study the phase holdup distributions of a pilot scale LSCFB system. A detail modeling on four different type spherical glass beads (500 and 1250 μm) and irregular shape lava rocks (500 and 920 μm) are used as solid phase with water as liquid phase. The densities of both the particles are comparable. In model development various auxiliary and primary liquid velocities, superficial solids velocity on radial phase distribution at different axial positions are considered. The competency of the developed models is examined by comparing the model predicted with experimental data of phase holdups at different radial and axial locations of the riser. ANFIS model successfully predict solids holdups distributions at various positions of the bed. It is revealed that under different superficial liquid velocities the solids holdup is higher for the glass beads as compare to lava rocks due to higher drag force imposed on the spherical shape particles. The solids holdup decreased with increasing liquid velocity at all axial locations. The non-uniformity of solids holdup in central region decreased axially as the flow is well developed at higher levels as revealed by both the models prediction and experimental observations. When compared with a previously developed ANN model, the ANFIS model shows a superior performance in predicting the LSCFB experimental data and their trends.