ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Detailed measurements of radial variations of turbulence intensity were made with a hot film anemometer in a concentric annulus of aspect ratio Ri/Ro = 0.0416 for a Reynolds number range 1,200 ≤ Re ≤ 3,000 using a Newtonian polyglycol water solution. Measurements were also made of excess entrance pressure gradients and the axial variation of pressure gradients.Based on the results of these measurements, it is concluded that the proposition of Lea and Tadros (1931), Rothfus (1948) and others that a transitional flow regime develops with a zone of turbulence near the inner core surrounded by a zone of laminar flow near the outer wall is false. The two-critical Reynolds number transitional regime proposed by Hanks and Bonner (1971) is verified to exist but their mathematical model for the interpretation of its cause is disproved. It is shown that at the lower critical Reynolds number predicted by Hanks and Bonner (1971) and by Hanks (1980) a transition does occur. It is conjectured that the new flow may be a type of complex laminar bifurcation flow described by Joseph (1976), although the present data do not permit a definite conclusion to be reached. This complex laminar flow in turn undergoes a transition to turbulent flow at a second critical Reynolds number, higher than the first, in qualitative accord with Hanks and Bonner's (1971) and Hanks' (1980) predictions, although the latter are not quantitatively correct because they are based on inadequate models of the transitional flow field.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690280515
