Masters Theses


"Tests were conducted in dry vacuum environment, on eight mechanically expanded finned tube heat exchangers (with 3/8 inch outer diameter tubes) with different geometries including variation in fin thickness, fin collar length, and net interference. One of the eight heat exchangers was also tested under wet conditions. A mathematical model was used to calculate the thermal contact conductance from the experimental data. An error analysis was performed to estimate the range of error in determining the thermal contact conductance. A correlation of the dry contact conductance in terms of fin number (actual fin collar length in contact with the tubes), fin thickness, net interference and unexpanded tube diameter was obtained.

The thermal resistances, the contact conductance, the error band of the contact conductance, and the correlation coefficients were calculated on a microcomputer. A scanning electron microscope was used to examine the contact region between the flat aluminum fin and the copper tube.

Comparisons of the contact conductance were then made between heat exchangers having different fin numbers (20, 14, and 6 fins per inch), and also between heat exchangers having different expansion. For a given fin number, it was observed that the contact conductance increases as the expansion increases. Also for a given radial expansion (net interference), it was found that the contact conductance increases with increasing fin number"--Abstract, page ii.


Sheffield, John W.

Committee Member(s)

Sauer, Harry J., Jr., 1935-2008
Hamblen, John W.


Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering


Berziet University
American Society of Heating, Refrigerating and Air-Conditioning Engineers


University of Missouri--Rolla

Publication Date

Spring 1984


xi, 103 pages

Note about bibliography

Includes bibliographical references (pages 76-77).


© 1984 Mahmoud Ahmed Abuebid, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Heat exchangers
Heat engineering -- Materials
Heat -- Conduction -- Measurement

Thesis Number

T 5034

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