Yu. S. Teplitskii

Horizontal particle mixing in a free fluidized bed

Horizontal particle diffusion in free fluidized beds is investigated experimentally.

About choice of particle parameters for visualization and diagnostics of free concentrated air vortices

The problem of the choice of parameters (density, size) of particle inertia for visualization and diagnostics of free vortices of various intensities (characteristic velocity, vortex funnel diameter) is considered. The dimensionless criterion (Stokes number) is used, which determines the peculiarities of solid particles behavior in concentrated vortex structures. An example of the choice of particle parameters for visualization of a laboratory-simulated air vortex funnel and debris cloud is described.

External heat transfer in polydispersed fluidized beds at elevated temperatures

The authors present results of a theoretical and experimental study of heat transfer in polydispersed fluidized beds of coarse particles at temperatures up to 1273 K.

Heat Exchange in a Tube Filled with Granular Bed

Results of modeling of the process of heat transfer from a circular tube filled with granular bed with boundary conditions of the first, second, and third kind have been presented. The physical characteristics of the wall zone and the relative value of its thermal resistance have been determined based on an analysis of experimental data on the nonstationary heat exchange of the unblown granular bed. Recommendations on calculation of the heat exchange at elevated temperatures have been given.

Heat transfer in a circulating fluidized bed

On the basis of similarity theory a relationship is established for calculating the conductive-convective component of the coefficient of heat transfer in a circulating bed. Recommendations on the calculation of the total coefficient of heat transfer in a high-temperature bed are given. The gas gap between the heat-transfer surface and the first row of particles is evaluated.

Heat transfer in fluidized beds

We propose a simplified model of external heat transfer in a fluidized bed. We compare calculated and experimental data, and recommend a computational procedure in polydisperse beds.

Expansion of an inhomogeneous fluidized bed

The expansion of an inhomogeneous fluidized bed in a column 700 mm in diameter is determined experimentally. A calculated correlation is obtained on the basis of a two-phase model.

Near-Wall Hydrodynamics of a Circulating Fluidized Bed

The available experimental data on the velocities of phases, concentrations of particles, size of clusters in the wall layer of a circulating fluidized bed, and also on the width of this zone have been generalized within the framework of similarity theory. An analysis of the relationship between the velocity of a cluster and its vertical dimension has made it possible to elucidate the character of gas flow around the cluster.

Resistance of a Circulating Fluidized Bed

Available experimental data on the resistance of the riser of a circulating fluidized bed under different conditions of control over its operation are generalized within the framework of similarity theory. Dependences for calculating the height of the fluidized bed formed in the lower part of the riser are obtained based on an analysis of the components of the resistance of this bed.

Mixing of Particles in a Circulating Fluidized Bed

A phenomenological model of longitudinal mixing of particles in a circulating fluidized bed is formulated. The model allows for the main features of the process: ascending motion of particles in the core of the bed and their descending motion in the annular zone (internal circulation of the solid phase); considerable changes in the concentration of particles and in the values of the ascending and descending zones over the bed height; external circulation of the solid phase and the effect of the near‐bottom fluidized bed on the process as a whole. The validity of the initial proposition is confirmed by comparison of calculated and experimental curves of mixing.