Experimental investigation of the behavior of non-spherical particles in a small-scale gas-solid fluidized bed

Abstract

The present work examined the effect of particle shape on the fluidization behavior at different inlet superficial gas velocities. The experiments are performed in a laboratory-scale 3D circular fluidized bed column of 1 m height and 0.067 m inner diameter with Geldart D particles of four different shapes. The effect of particle shape on pressure drop, bed expansion, and solids holdup are analyzed. Non-spherical particles have lower minimum fluidization velocities and higher bed expansion than spherical particles. The shape of particles significantly impacts the solids holdup, and it has been observed that spherical particles exhibit a higher solids holdup at the same superficial velocity. The time series analysis of the pressure signals is investigated by the frequency domain method using the Fast Fourier Transform (FFT). The FFT is implemented in Matlab R2021b to obtain the Power Spectral Density (PSD). The analysis of the PSD pattern shows the flow regime transition with the change in the particle shape. PSD pattern has observed a broad range of frequencies between 1 and 5 Hz. The dominant frequency of around 3 Hz corresponds to the bubbles or slugs that pass the bed.