Because the nanopowders fluidization is characterized by a homogeneous
expansion of the bed without bubbles, a combination of Richardson-Zaki equation
with fractal analysis of agglomerates, proposed by Nam et al. (13), has been used in
order to estimate the agglomerates properties by working out the experimental bed
expansion data. In particular, agglomerate sizes of 60 μm and 200 μm and
agglomerate densities of 450 kg/m3 and 300 kg/m3 have been obtained for Al2O3 and
SiO2 powders respectively with reference to the sound assisted fluidization test
carried out at SPL=140 dB and f=120 Hz.