SETTLING VELOCITIES OF NONSPHERICAL PARTICLES IN NON-NEWTONIAN POLYMER-SOLUTIONS

The free fall velocity of numerous cylinders (of perspex, glass and steel), needles (of steel) and rectangular prisms (of perspex) falling with their major axis parallel to the direction of gravity has been measured in shear thinning polymer solutions. The measurements have been carried out in three to four fall tubes of different inside diameters to correct the terminal velocity data for wall effects. The present set of experimental results encompass the following ranges of conditions: L/d ratio of needles and cylinders from 5 to 50 and rectangular prisms with ratios 1:1:1 to 1:5:5; 0.05<Re<150; 6.5 less-than-or-equal-to V less-than-or-equal-to 540 mm s-1; 0.77 less-than-or-equal-to n less-than-or-equal-to 1 and 0.00317 less-than-or-equal-to (d(eq)/D) less-than-or-equal-to 0.68. There are altogether 675 individual data points which have been correlated using a simple expression involving the usual drag coefficient and Reynolds number. The expression presented herein also describes the scant literature data for cylinders and cones satisfactorily.