Steady Laminar Flow of Non-Newtonian Fluids in the Inlet Region of Rectangular Duct

A steady laminar flow of incompressible Non-Newtonian fluids (power law fluid and Sutterby fluid) in the inlet region of rectangular duct was analyzed by finite difference methods. The main results obtained are as follows. (1) The pressure drop of a Non-Newtonian fluid in the inlet region is smaller than that of a Newtonian fluid and its measure increases with an increase in Non-Newtonian property of the fluid. (2) The velocity in the duct center of a Non-Newtonian fluid in the inlet region is smaller than that of a Newtonian fluid and its measure increases with an increase in Non-Newtonian property of the fluid. (3) The velocity profile in a Non-Newtonian fluid becomes flatter than that in a Newtonian fluid, and the velocity in the inlet region develops retaining flatter profile. (4) The additional pressure loss in the inlet region is smaller in a Non-Newtonian fluid than in a Newtonian fluid and its measure increases with an increase in Non-Newtonian property of the fluid. (5) The inlet length of a Non-Newtonian fluid is larger than that of a Newtonian fluid. (6) The pressure drop and the velocity in the duct center of a Non-Newtonian fluid in the inlet region of a rectangular duct decrease with an increase in the aspect ratio of the duct as those of a Newtonian fluid.