Local mass transfer and flow visualization around a cylinder in a liquid-solid fluidized bed /Lokalni prenos mase i vizualizacija toka oko cilindra u fluidizovanom sloju tecno-cvrsto

Adsorption method has been used for flow visualisation and determination of the local and average mass transfer coefficients around a horizontal cylinder in a liquid-solid fluidized bed. The obtained concentration fields on the adsorbent (silica-foils) represent a clear qualitative flow pattern around the cylinder. By comparison of the concentration fields around the cylinder in the single-phase flow and in the fluidized bed, a significant disturbance of the boundary layer by fluidized particles can be observed. Local mass transfer coefficients were shown to be dependent on the angular position around the cylinder with the maximum determined at the angle 140[degrees] (measured from the stagnant point 0[degrees]). Selected correlations were applied to predict the average mass transfer coefficients and the two best have shown deviations from the experimental data up to 5 %. Keywords: Mass transfer coefficients; adsorption method; flow past cylinder; concentration fields.