Measurement and prediction of solid sphere trajectories in accelerated gas flow

Trajectories are measured and compared with computed trajectories of solid particles with a diameter of 1–2 mm in downward gas flow near a solid cylinder with a diameter, dc, of 25 mm. The Reynolds number based on dc has been varied from 3000–13,000. The particle Reynolds numbers, based on the relative velocity |UG - Up|, ranged from 0 to 2000. Of all forces other than gravity, drag is dominant, although the pressure gradient and added mass forces for Rec > 10,000 have the same order of magnitude. The Basset force can be neglected. The correlation [3], originally derived by Sridhar and Katz (1995) for the lift force coefficient of bubbles, has been found to be appropriate for freely moving solid particles with shear number less than 0.04.