Premium
Measurements of bubbles formed in boiling Methanol
Author(s) -
Perkins A. S.,
Westwater J. W.
Publication year - 1956
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.690020411
Subject(s) - boiling , thermodynamics , bubble , chemistry , tube (container) , nucleate boiling , heat transfer , heat flux , mechanics , materials science , composite material , physics
The photographic method was used to measure bubble sizes and frequencies for methanol boiling at atmospheric pressure outside a 3/8‐in. O.D., steam‐heated, horizontal copper tube. The average temperature of the tube was measured by use of the tube as a resistance thermometer. For nucleate boiling at heat fluxes up to 80% of the maximum, the product of bubble diameter and frequency was constant at 4 in./sec. In this region both the Rohsenow equation and the Forster‐Zuber equation gave good predictions of the heat transfer. At higher fluxes the product f × D increased and the equations were much less suitable. The critical temperature difference for copper to methanol was not a single value but was a region extending from 52° to 62°F. The heat flux was nearly constant throughout this range at a maximum of 115,000 B.t.u./(hr.)(sq. ft.). For film boiling, f × D was nearly constant at 11 sec. −1 Bromley's equation was unsuitable for Δ T values less than 180°F., but it became applicable at this Δ T . The use of Nusselt's equation for steam condensing inside the tube was found to be satisfactory, proof that the slight slope of the tube was sufficient to permit adequate condensate drainage.