Premium
Effect of fluid viscosity on combined free forced convection flow phenomena in vertical pipes
Author(s) -
Greene Howard L.,
Scheele George F.
Publication year - 1970
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690160630
Subject(s) - natural convection , mechanics , dimensionless quantity , combined forced and natural convection , thermodynamics , viscosity , reynolds number , convection , newtonian fluid , heat flux , forced convection , flow (mathematics) , chemistry , materials science , heat transfer , physics , turbulence
Distorted velocity and temperature profiles are measured at low Reynolds numbers for upflow constant flux heating of water and two viscous Newtonian sucrose solutions in a long vertical pipe. Heated L / D 's ranged from 29 to 251. Experimental profiles at L / D = 251 show general agreement with the fully developed profile theory based on natural convection effects, but additional profile distortion, attributed at least in part to radial viscosity variation with temperature, is observed even with water. Natural convection induced transition to disturbed flow occurs for all three liquids as the ratio of heat input to flow rate is increased. The transition process involves the growth in amplitude and radial spread of initially small disturbances. Transition conditions and the dimensionless radial location of the first detectable instability are related to features of the distorted flow fields.