Circulation of Geldart D type particles: Part II—Low solids fluxes: Measurements and computation under dilute conditions

In Part I of this paper, solids slugging phenomena were studied for high solids fluxes. In this study, the solids slugging was eliminated for extremely low solids fluxes. Here, gamma ray densitometry and PIV techniques were used to measure radially averaged solids volume fractions, and solids laminar and turbulent properties near the wall, respectively.The PIV system measured turbulent properties for solids, such as stresses, granular temperatures, and dispersion coefficients, non-invasively near the wall, in the developing region. This study was the first known measurement of solids dispersion coefficients in the axial and radial directions, using the PIV technique. A two-dimensional kinetic theory based IIT CFD code was used to perform simulations. The measured and computed radially averaged total granular temperatures, axial and radial solids and axial gas dispersion coefficients, reasonably agreed with the literature. This study also showed the capabilities of the kinetic theory based CFD codes to reasonably match the solids dispersion coefficients measured using the PIV technique.