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Heat transfer to water in an annulus
Author(s) -
Miller Philip,
Byrnes James J.,
Benforado David M.
Publication year - 1955
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.690010420
Subject(s) - annulus (botany) , reynolds number , thermodynamics , mechanics , heat transfer , heat transfer coefficient , boundary layer , materials science , chemistry , turbulence , physics , composite material
A limited number of measurements were made of the heat transfer coefficient from an electrically heated rod to water flowing in an annulus. Tests were performed at Reynolds numbers ranging from 5,000 to 22,000 (based on equivalent diameter), water temperatures of 70° and 125°F., and relatively high heat fluxes of 52,000 to 208,000 B.t.u./(hr.) (sq. ft.). The annulus dimensions were 0.625 in. I.D. and 0.840 in. O.D. The coefficients varied as the 0.8 power of the velocity; they were 20% higher than predicted by use of Colburn's equation for flow inside pipes with the equivalent diameter. Over the range of conditions studied, it was found that the thermal boundary layer was fully developed in 1 1/8 in. ( L h / D e =5).