Aerodynamics and Heat and Mass Transfer of Fluidized Particle Beds in Vortex Chambers

Abstract

This article is devoted to the results of studying the heat and mass transfer processes in "particle-gas" systems proceeding in a bed fluidized in the field of centrifugal force. It has been shown that the processes are essentially intensified under these conditions as compared to those in fluidized beds. Under fluidization in the field of centrifugal force it is possible to obtain a steady uniform vorticallayer of particles, which is uniformly blown through by gas with relative velocities exceeding the velocity of the particle swirling in a carrying medium. There exists a possibility of controlling this layer lind the residence time of particles.This article presents the results of experimental and computational studies of aerodynamics and heat and mass transfer of vortex chambers with a fluidized bed ofparticles. The peculiarities of the particle bed formation depending on the bed mass, dispersed composition, aerodynamics, and geometric characteristics of vortex chambers have been analyzed. The study of the heat and mass transfer between tire heat carrierflux and particles is carried out for the case ofparticle bed heating in the vortex chamber and tire evaporation of tire surface moisture from a dispersed material.Tire problems of the use of centrifugal fluidization in different technological processes are discussed.

Modeling fast biomass pyrolysis in a gas–solid vortex reactor

“…The past decades have seen a relative resurgence RFB-SG research in several different fields, including nuclear technologies [10,11], drying applications [12,13], and chemical reactors [14][15][16]. The RFB-SG technology has hybrid characteristics of both fluidized bed and packed bed reactors.…”

On the mechanisms of secondary flows in a gas vortex unit

“…29 The quantitative deviation of the azimuthal velocity profile from the hyperbolic free-vortex flow profile arises from the fact that the friction losses encountered by the gas at the end-walls reduce U h to some extent. 33 However, the qualitative trend of increasing U h with decreasing radius is retained. In the exhaust region of the unit (0 < r < 0.0075 m), the BR and an intense turbulence develop causing the swirling structure to break.…”

Rotating fluidized bed with a static geometry: Guidelines for design and operating conditions

“…1) (Anderson et al, 1972;Volchkov et al, 1993;Goldshtik et al, 1997;de Broqueville, 2005de Broqueville, , 2006aDe Wilde et al, 2006, 2007aDe Wilde andde Broqueville, 2007, 2008). The fluidization gas is forced to leave the fluidization chamber via a central chimney, introducing a radial motion of the gas.…”

“…An optimum inlet slot width ensures substantial tangential motion resulting in sufficiently large centrifugal accelerations to maintain the solids inside the bed and minimizes solids losses through entrainment and elutriation. High radial and tangential gas-solid slip velocities are expected to significantly improve heat transfer (Volchkov et al, 1993;de Broqueville and De Wilde, 2009). Despite higher fluidization gas velocities, excellent gas-solid separation can be obtained due to the centrifugal force (Sazhin et al, 2008).…”