HEAT TRANSFER AND DRAG REDUCTION IN PIPES OF VARIOUS GEOMETRIES

The friction factors and heat transfer coefficients have been determined for the turbulent flow of water and 100 ppm aqueous solutions of polyacrylamide in circular, square and rectangular pipes. The heat transfer reduction in the circular and square pipes was found to be larger than the drag reduction: 30% as compared to 20%. In the rectangular pipe, the reduction of the heal transfer was about equal to the drag reduction (similar or equal to 15%) and much less than in the other geometries. The Colburn analogy between heat and momentum transfer was found to be valid for the circular pipe but not for the other geometries.