Dynamic behavior of freely rising buoyant solid spheres in non-Newtonian liquids

✍ Scribed by K. H. Dewsbury; D. G. Karamanev; A. Margaritis

• Publisher: American Institute of Chemical Engineers
• Year: 2000
• Tongue: English
• Weight: 106 KB
• Volume: 46
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690460107

✦ Synopsis

Abstract

The results of the hydrodynamic study of rising solid spheres in non‐Newtonian (pseudoplastic) fluids are reported. The hydrodynamic parameters including drag coefficient, trajectory of rise, and terminal velocity were determined. The behavior of free‐rising spheres was compared to that of falling spheres in the same type of fluids to see if any differences exist. It was observed that rising solid spheres behave differently from falling solid spheres at higher Reynolds numbers in non‐Newtonian (pseudoplastic) fluids. At high Reynolds numbers rising solid spheres display a spiraling motion, while falling spheres display a linear trajectory. The angle between the velocity vector and horizontal plane of the spiraling trajectory was 60°. The spiraling trajectory led to a drag coefficient that was more than two times higher for rising solid spheres than that established for falling spheres in the Newton's law range in a non‐Newtonian (pseudoplastic) liquid. The first ever correlation is proposed to calculate the drag coefficient of freely rising light solid spheres in non‐Newtonian (pseudoplastic) fluids.