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Flow patterns in viscoelastic liquids upstream of orifices
Author(s) -
Oliver D. R.,
Bragg R.
Publication year - 1973
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450510304
Subject(s) - body orifice , flow (mathematics) , conical surface , mechanics , hele shaw flow , orifice plate , flow coefficient , materials science , flow velocity , viscoelasticity , isothermal flow , physics , open channel flow , composite material , engineering , mechanical engineering
The flow patterns obtained when aqueous polyacrylamide solutions flow into orifices are photographed. The polymer concentrations are 0.01, 0.03 and 0.10 per cent, the orifice diameters 1.27, 0.95, 0.50, 0.20 and 0.10 cm and the flow velocities 7‐700 cm/sec. Various flow patterns are identified, including the well‐defined conical form. The semi‐angle of the cone decreases with decreasing orifice size and also depends on flow velocity, particularly when the larger orifices are being used. Cone angle also depends on the concentration of the solution. The flow pattern sometimes changes abruptly when flow velocity is increased; flow instability is often present. Finally, it is suggested that the flow pattern is established as a result of interplay between extensional forces present in the liquid at the orifice and viscous and kinetic effects in the upstream fluid.