The objective of this work is to study the effect of confining walls on the free settling of spherical particles along the axes of five vertical cylindrical tubes in Newtonian and non-Newtonian liquids. Experimental results were predominantly obtained in the particle flow region between the Stokes and the Newton regimes (intermediate region) and displayed Reynolds numbers in the ranges 0.7<Re<311 for aqueous glycerine solutions and 0.2<Re<340 for aqueous carboximethilcellulose solution considering the range of 0<<FONT FACE="Symbol">b</font><0.55. These results allowed to analyze the procedure for estimating vt<FONT FACE="Symbol">¥ </font>as a function of b based on vt data and present correlations for estimating the wall effects on the fall of spheres in Newtonian liquids as well as for the characteristic shear rate of spheres in non-Newtonian fluids.
wall effects; spherical particles; Newtonian and non-Newtonian liquids
