Publicado 6 números por año
ISSN Imprimir: 2152-5102
ISSN En Línea: 2152-5110
Indexed in
Particulate Pressure in Disperse Flow
SINOPSIS
We develop a model to describe the velocity variance and particulate pressure in fluidized beds, and also in one-dimensional disperse flows. These quantities involve contributions caused by 1) short-scale pseudoturbulent fluctuations of particles in the dense phase of a fluidized bed, and 2) long-scale fluctuations due to macroscopic flow patterns, such as rising bubbles that are practically devoid of particles. Energy comes to the pseudoturbulent fluctuations from the relative motion of the ambient fluid as it interacts with random fluctuations of the dispersion concentration, and also from gravity working at density fluctuations. Inter-particle exchange by momentum and energy is assumed to be carried out by particle collisions, in which case the particles may be approximately treated as statistically independent, and their fluctuations can be regarded as nearly isotropic. The long-scale contributions to velocity variance and particulate pressure are evaluated on the basis of a simple dimensionality consideration. In some dispersion flows, the gas slip velocity may greatly exceed the particle terminal velocity, and consequently, the pseudoturbulent particulate pressure turns out to be much larger than that in a fluidized bed of the same particles at the same concentration. The theoretical conclusions are proven to be in good keeping with all experimental data for fluidized beds available to date.
-
Lettieri Paola, Mazzei Luca, Challenges and Issues on the CFD Modeling of Fluidized Beds: A Review, The Journal of Computational Multiphase Flows, 1, 2, 2009. Crossref
-
Wang Junwu, Ge Wei, Collisional particle-phase pressure in particle-fluid flows at high particle inertia, Physics of Fluids, 17, 12, 2005. Crossref
-
Huang X., Liu Z., Granular Temperature in Bubbling Fluidized Beds, Chemical Engineering & Technology, 31, 9, 2008. Crossref
-
Ye M., van der Hoef M.A., Kuipers J.A.M., The effects of particle and gas properties on the fluidization of Geldart A particles, Chemical Engineering Science, 60, 16, 2005. Crossref
-
Cody George D., Johri Jayati, Goldfarb David, Dependence of particle fluctuation velocity on gas flow, and particle diameter in gas fluidized beds for monodispersed spheres in the Geldart B and A fluidization regimes, Powder Technology, 182, 2, 2008. Crossref
-
Wang Junwu, Ge Wei, Multi-scale analysis on particle-phase stresses of coarse particles in bubbling fluidized beds, Chemical Engineering Science, 61, 8, 2006. Crossref
-
Zivkovic V., Biggs M. J., Glass D., Granular pressure in a liquid-fluidized bed as revealed by diffusing wave spectroscopy, AIChE Journal, 58, 4, 2012. Crossref
-
Sergeev Y.A., Swailes D.C., Petrie C.J.S., Stability of uniform fluidization revisited, Physica A: Statistical Mechanics and its Applications, 335, 1-2, 2004. Crossref
-
Wang Junwu, Zhao Bidan, Li Jinghai, Toward a mesoscale-structure-based kinetic theory for heterogeneous gas-solid flow: Particle velocity distribution function, AIChE Journal, 62, 8, 2016. Crossref
-
Wang Junwu, Continuum theory for dense gas-solid flow: A state-of-the-art review, Chemical Engineering Science, 215, 2020. Crossref
-
Cody G. D., Particle Fluctuation Velocity in Gas Fluidized Beds - Fundamental Models Compared to Recent Experimental Data, MRS Proceedings, 627, 2000. Crossref
-
Zhao Bidan, He Mingming, Wang Junwu, Multiscale kinetic theory for heterogeneous granular and gas-solid flows, Chemical Engineering Science, 232, 2021. Crossref
-
Wang Junwu, A Review of Eulerian Simulation of Geldart A Particles in Gas-Fluidized Beds, Industrial & Engineering Chemistry Research, 48, 12, 2009. Crossref
-
Siginer Dennis A., Constitutive formulations for non-colloidal suspensions, Journal of Molecular Liquids, 355, 2022. Crossref