Drag reduction in developing pipe flow with polymer injection
Drag-reduction measurements obtained for polymer injection into the developing boundary layer of a pipe are discussed. Tests were conducted in a 305-mm diameter 60-m long rough steel pipe. Concentrated solutions of Polyox WSR 301 were injected through a perforated wall section located 3.5 diameters from the pipe entrance. Injection concentrations varied from 100 ppm to 2,400 ppm; Reynolds numbers from 3 x 10/sup 5/ to 3 x 10/sup 6/, polymer injection rates from 1,900 cu cm/sec to 14,000 cu cm/sec, and maximum wall shear stresses were in excess 3,000 dynes; sq cm with injection. This high drag reduction reduced with distance and levelled off to the value for homogeneous flow to the value for homogeneous flow as measured in the fully developed flow region. It became constant near the location where the concentration profile became uniform. The drag reduction near the injector was greater than that previously measured for porous wall or slot injectors. Turbulent diffusion away from the wall is less for the injected polymer than for water injection. The total drag reduction over the inlet reach was not affected by the injection concentration but did vary with Reynolds number. (18 refs.)
- Research Organization:
- Colorado State Univ., Fort Collins
- OSTI ID:
- 6581394
- Report Number(s):
- CONF-7409184-
- Journal Information:
- Proc. Int. BHRA Drag Reduction Conf.; (), Conference: International BHRA drag reduction conference, Cambridge, UK, 4 Sep 1974
- Country of Publication:
- United States
- Language:
- English
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