Form Approved
REPORT DOCUMENTATION PAGE
OMB No. 0704-0188
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1. AGENCY USE ONLY (Leave blank)
2. REPORT DATE
3. REPORT TYPE AND DATES COVERED
November 1995
4. TITLE AND SUBTITLE
5. FUNDING NUMBERS
Effect of Condensation on Performance and Design of
Extended Surfaces
ARO Contract
DAAL03-91-C-0034
6. AUTHORS
TCN 94-077 No. 1140
Virgil J. Lunardini and Abdul Aziz
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
8. PERFORMING ORGANIZATION
REPORT NUMBER
U.S. Army Cold Regions Research and Engineering Laboratory
72 Lyme Road
CRREL Report 95-20
Hanover, New Hampshire 03755-1290
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
Army Research Office
Research Triangle Park
Raleigh, North Carolina 27709-2211
11. SUPPLEMENTARY NOTES
12a. DISTRIBUTION/AVAILABILITY STATEMENT
12b. DISTRIBUTION CODE
Approved for public release; distribution is unlimited.
Available from NTIS, Springfield, Virginia 22161
13. ABSTRACT (Maximum 200 words)
Heat transfer surfaces operating in cold regions often involve condensation. The analytical and experimental
progress made in understanding the process of condensation on extended surfaces (fins) is reviewed in de-
tail. The review covers condensation of pure vapor as well as dehumidification of air. The analytical models
discussed range from simple Nusselt-type analysis to the three-dimensional conjugate approach, in which
the conservation equations for the condensate film are tightly coupled to conduction in the fin. A separate
section discusses the topic of dehumidification of air on finned cooling coils. Other topics reviewed include
condensation on horizontal integral-fin tubes, convective condensation in internally finned tubes, and con-
densation in micro-fin tubes. Although condensation on horizontal integral-fin tubes appears to be well un-
derstood, our understanding of convective condensation in internally finned tubes, particularly the micro-fin
tubes, is very limited. Furthermore, there exists no established methodology for designing extended surfaces
for condensation applications. This report contains several examples illustrating the theoretical results that
provide some insight into the design process.
14. SUBJECT TERMS
15. NUMBER OF PAGES
59
Condensation
Heat transfer
16. PRICE CODE
Finned surfaces
Refrigeration
17. SECURITY CLASSIFICATION
18. SECURITY CLASSIFICATION
19. SECURITY CLASSIFICATION
20. LIMITATION OF ABSTRACT
OF REPORT
OF THIS PAGE
OF ABSTRACT
UNCLASSIFIED
UNCLASSIFIED
UNCLASSIFIED
UL
Standard Form 298 (Rev. 2-89)
NSN 7540-01-280-5500
Prescribed by ANSI Std. Z39-18
298-102
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