ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
AUGMENTATION OF CONDENSATION HEAT TRANSFER BY INTERNALLY FINNED TUBES AND TWISTED TAPE INSERTS
Resumo
Heat transfer and pressure drop data were taken during condensation of R-113 inside seven horizontal tubes. One tube was smooth, four were internally finned with different outside diameters and fin geometries, and the remaining two had twisted tape inserts with different pitch to diameter ratios. The smooth tube results were used to identify, among existing smooth tube correlations, the best predictors of the experimental
measurements of this investigation. For each of
the augmentation techniques tested, new appropriate
modifiers were identified and applied to the smooth
tube correlations to bring about the best agreement
between the measurements of the augmented tubes and
predictions. Over the mass flux range tested, the
best performing internally finned tube enhanced the
heat transfer coefficients by 51% above the smooth
tube, on a nominal area basis. The twisted tape
inserts enhanced the heat transfer coefficients by
as much as 23% over the smooth tube, on a nominal
area basis. Correlations were proposed for predicting
the overall average heat transfer coefficients
and pressure drop for the two augmentation
techniques tested.