Jia-Bo Hwang

Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Mechanical Engineering


It has long been known that the heat transfer from a solid body to an ambient fluid can be increased by increasing the surface area of the solid body. Extended surfaces, or fins, are indispensable for compact heat exchangers. Geometrically, fins may be classified as straight fins, annular fins, and rod fins or spines. In most applications of fins, a fluid is circulating inside the fin-supporting pipe while the outside is exposed to another ambient fluid. The purpose of fin analysis is to find the temperature distribution in the fin and the heat transfer from the fin to the ambient fluid, i.e., the fin efficiency, which is the basis of comparing various fin designs. Conduction is the heat transfer mechanism in the fin and convection and radiation occur at the surface. The amount of radiation heat transfer, in accordance with Stefan-Boltzmann's law, is proportional to the difference between the fourth power of the temperature of the fin and the ambient fluid. The fourth-power term makes the fin equation non-linear and difficult to solve analytically. Earlier researchers linearized the radiation term by replacing the fourth power law by an equivalent convection coefficient times the difference of the temperature in order to obtain an analytical solution. (See more in text)

Library of Congress Subject Headings

Heat -- Transmission



Number of Pages



South Dakota State University