Dynamical features of the solid motion in gas–solid risers

Non-intrusive measurement and hydrodynamics characterization of gas–solid fluidized beds: a review

“…Based on the particle backflow phenomenon in a riser, Bhusarapu et al [105,146,181] measured the solids circulation rate, overall solids flux and turbulent parameter profiles. More dynamic properties were characterized by processing the RPT signals through statistical analysis, non-linear dynamics analysis, symbolic dynamics analysis and data mining [182][183][184]. Moreover, a multiple radioactive particle tracking (MRPT) technique has been developed to determine the trajectories of multiple tracers in the three dimensions.…”

DSMC prediction of granular temperatures of clusters and dispersed particles in a riser

“…Simulations indicate that the granular temperatures of clusters are lower than those of dispersed particles. The averaged granular temperatures of clusters and dispersed particles are 468.89 (cm/s) 2 and 976.62 (cm/s) 2 , respectively. Because the averaged number of particles in the clusters is about 131 at the threshold value ε s + 2σ, the ratio of the total fluctuating energy of cluster to a single particle is (n c n s mθ c )/(mθ d ) = 131 × 468.89/976.62 = 62.9.…”

“…The continuing process of formation, breakup, and reformation of particle clusters is a basic cause for the high slip velocity between gas and solid phases, and for the mixing and backflow of solids in risers. Experiments show that flow of particle clusters features differently from that of the dispersed particles in the riser [1][2][3][4][5]. Flow behavior of particle clusters affects the particle mixing, and heat and mass transfer in the CFB riser.…”

A method for characterising solids translational and rotational motions using Multiple-Positron Emission Particle Tracking (Multiple-PEPT)

“…Other tomographic studies have been made on the dynamics of solids in multiphase flows. Bhusarapu et al (2007) use radioactive tracers to study circulating fluidised beds, and identify differences in the behaviour between the fast fluidised and dilute phase transport flows, whilst Razzak et al (2007) use electrical resistance tomography to study these flows.…”