AbstractDrag reduction in the turbulent flow of aqueous solutions of polyacrylamide and poly(ethylene oxide) was studied in tubes and parallel plates. Friction factors were determined at Reynolds numbers up to 20,000 for polymer concentrations of 0.10 to 400g/m3in glass tubes run in a constant‐head, gravity flow system in which the velocity was determined from the horizontal distance traveled by the effluent stream while falling a set vertical distance; and in Plexiglas parallel plates run in a constant‐velocity, machine‐driven system in which the pressure drop between two points on the plates was measured with a differential pressure transducer. A general method of correlating fraction laminarization or drag reduction effectiveness with polymer concentration for Reynolds numbers above 6000 was developed in which two master curves, one for very low concentrations which was the same for both tubes and parallel plates, and one for higher concentrations which differed for tubes and parallel plates, were found to represent the data very well for both polymers and all conduit sizes and Reynolds numbers. Additionally, relationships were found between conduit size and maximum fraction laminarization and optimum polymer concentr
展开▼
