Mass and momentum transfer in packed beds of spherical inert particles

Mass transfer coefficients between fluid and immersed sphere in liquid dense and loose packed beds of spherical inert particles have been studied experimentally using column 40 mm in diameter. Mass transfer data were obtained by studying transfer of benzoic acid from a large spherical particle to flowing water using the disssolution method. In all runs mass transfer rates were determined in the presence of inert spherical glass particles 0.54, 0.68, 1.20, 1.94, 2.98 and 4.98 mm in diameter. Measurements have covered a particle Reynolds number range from 0.35 to 400 and one Schmidt number (25°C) 969. Experimental data are correlated by the widely used general form, j D = f(Re p ). The resulting correlation for packed beds, which covers dense and loose packed beds, is j D = 0.395ε -1,2 Re p -0,39 . In the same experimental systems a relationship between friction factor and particle Reynolds number has been studied. The results indicate that numerical constants in Ergun equation are system specific.