Polymer Injection into a Developing Boundary Layer.
Final rept. 1 Oct 74-31 Mar 76,
COLORADO STATE UNIV FORT COLLINS HYDRO MACHINERY LAB
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This report describes the last phase of a study on the drag reduction at the entrance region of a 12-inch pipe by injection of polymer solutions. In this phase of the study the effect of injecting concentrated solutions of WSR 301, up to 3600 ppmw, was examined. This study indicates that the local friction downstream from the injector can be considerably reduced by increasing the discharge of the polymer injected into the pipe. However, the injection disturbs the flow and increases the pressure losses across the injector. When the total drag reduction of a given pipe length XD, which includes the losses due to the injection, is considered, it is found that different optimal conditions exist for reducing the drag of short pipe sections and for reducing the drag of long pipe sections. This report also summarizes a study of drag reduction in a pipe flow of Calgon TRO-375 solutions. For certain tests, this polymer caused an apparent increase in the effective roughness of the pipe walls. In addition, the report summarizes a study of the effect of a polymer WSR 301 on the cavitation characteristics of a pipe orifice. Author
- Fluid Mechanics