Drag on Two Co-axial Rigid Spheres Moving Normal to a Plane: Newtonian and Carreau Fluids
Advancing the chemical engineering fundamentals
Particulate Systems (T2-3P)
Keywords: sedimentation, two coaxial rigid spheres, Newtonian and Carreau fluid, boundary effect, normal to a plane, drag coefficient
The boundary effect and the presence of a nearby entity on the drag of a rigid entity is investigated by considering the movement of two identical, rigid, coaxial spheres normal to a plane in both a Newtonian and a Carreau fluid for a low to medium large Reynolds number. The parameters key to the phenomenon under consideration, including the nature of the fluid, the separation distance between two particles, the distance between particle and the plane, and the Reynolds number, on the drag coefficient are discussed. We show that the influence of a boundary on the drag coefficient is more important than that of the nature of a fluid and that of the distance between two particles. The variation of the drag coefficient as a function of Reynolds number for a Carreau fluid is similar to that for a Newtonian fluid. Due to the shear-thinning nature of the former fluid the drag coefficient in the former is smaller than that in the latter fluid. The magnitude of the drag coefficient is inversely proportional to the Carreau number. The influence of the index parameter of a Carreau fluid becomes appreciable when the Carreau number is sufficiently large. A correlation relation between the drag coefficient and the key parameters of a system is developed for both Newtonian and Carreau fluids.
Presented Monday 17, 13:30 to 15:00, in session Particulate Systems (T2-3P).
