ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
An experimental study of local heat transfer coefficients in a baffled tubular heat exchanger for five baffle spacings and two tube spacings (23/16-in.-pitch, four-tube bundle, and 11/4-in.-pitch, fourteen-tube bundle) is reported. Shell-side air-flow rate was constant for all runs. The variation of the local heat transfer coefficient around the tubes and along the length of the tubes for each tube spacing and baffle spacing was investigated. Average shell-side heat transfer coefficients were evaluated from local values and were found to agree with average values reported in the literature. These average values varied with the six-tenths power of the mass velocity in the heat exchanger. The average Nusselt number and the pressure drop across the exchanger each increased at about the same rate as the number of baffles was increased from two to ten. The average heat transfer rate decreased with decreased tube spacing. This effect was evident from the local heat transfer coefficients, and it is explained on the basis of the mechanism of flow around tubes. An eddy flow zone was detected between the baffles. Average heat transfer rates in the eddy and crossflow zones were almost equal and were about 15% below the average rate in the longitudinal-flow zone. The variation of the average heat transfer coefficient along a tube definitely showed the effects of baffles. High coefficients occurred in the baffle holes and in the baffle windows.
Additional Material:
18 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690040320
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