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Combined free and forced convection in a constant temperature horizontal tube
Author(s) -
Jackson T. W.,
Spurlock J. M.,
Purdy K. R.
Publication year - 1961
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.690070111
Subject(s) - grashof number , nusselt number , laminar flow , prandtl number , thermodynamics , turbulence , forced convection , reynolds number , natural convection , mechanics , tube (container) , combined forced and natural convection , chemistry , heat transfer , materials science , physics , composite material
An experimental study of superposed free and forced convection for air in a horizontal tube is reported. The laminar Nusselt number, based on the log mean temperature difference, ranged from 29.9 to 15.2; the laminar flow Graetz number, based on the bulk or average temperature of the air, ranged from 33 to 1,300, the Grashof‐Prandtl modulus based on properties of air at the wall temperature ranged from 1.1 × 10 6 to 2.2 × 10 6 . The Grashof number utilized the log mean temperature difference. An analysis of the system from a macroscopic viewpoint led to the determination of an equation which fits the laminar flow experimental data in the range of Graetz numbers from 60 to 1,300. An equation was also found for the turbulent data.