Psychostimulant Use for Children with ADHD in Australia

Heat transfer and pressure drop were measured for flow of water, mineral oil, and aqueous solutions of viscoelastic polymers through a vertical tube filled with porous media. The heated stainless steel test section has an inside diameter of 2,25 cm, and is 200 diameters long. The porosity was varied from 0.32 to 0.68 by using uniform spherical glass beads. Uniform heat flux thermal boundary condition was imposed by passing direct electric current through the tube wall. Over a range of the parameters 8 < Re < 31,000, 7 < Pr < 245, 0.22 < d/D < 0.6, and polymer concentration from 100 to 500 parts per million, the friction factor data for Newtonian fluids agreed with the predictions in the literature. Drag reduction was noticed in the turbulent flow of dilute viscoelastic polymer solutions (Praestol at 100 and 200 wppm; polyox at 500 wppm) at (phi) = 0.68. Viscoelastic effect on heat transfer was insignificant. A new correlation was proposed for predicting heat transfer to Newtonian as well as viscoelastic flows through confined porous media.