Film condensation of steam on externally finned horizontal tubes
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Authors
Flook, Frederick A.
Subjects
steam
condensation
filmwise
tube
external fin
heat-transfer coefficient
enhancement
condensation
filmwise
tube
external fin
heat-transfer coefficient
enhancement
Advisors
Marto, P.J.
Wanniarachchi, A.S.
Date of Issue
1985-03
Date
March 1985
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
Filmwise condensation measurements of steam were made on horizontal finned tubes under vacuum and near-atmospheric conditions. Data were obtained for copper tubes with fins of rectangular, triangular, trapezoidal, and parabolic cross sections, and for a commercially-available finned tube. A stainless steel finned tube was also tested to investigate the effect of thermal conductivity.
Maximum enhancements of about 4.8 were obtained under vacuum conditions, and about 6.9 at atmospheric pressure, compared to a smooth tube having an outside diameter equal to the root diameter of the finned tubes. The optimum fin spacing was found to be about 2.0 mm for rectangularly shaped-fins with a fin thickness of 1.0 mm, and fin height of 0.5 and 1.5 mm. Fins with a parabolic shape were shown to perform better than fins of rectangular shape, and fins were shown to degrade the performance of stainless steel tubes. The effects of vapor shear were shown to have only a small influence on the steam-side heat-transfer coefficient. A theoretical model proposed by Webb et al. [25] was found to underpredict the experimental data. Several suggestions to modify this model are described.
Type
Thesis
Description
Series/Report No
Department
Mechanical Engineering
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
NPS 69-85-002
Sponsors
National Science Foundation Agreement No. MEA82-03567
Funder
National Science Foundation Agreement No. MEA82-03567
Format
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.