CHARACTERISTICS OF A STRAIGHT FIN WITH ENERGY RELEASE

Abstract

The heat conduction equation for a straight fin with an arbitrary profile in the presence of energy release in the fin is obtained in the article. The resulting equation differs from the approximate equation given in the literature by the presence of energy release and a more accurate determination of the length of the arc element. The equation is solved for the fin of a rectangular profile with continuously operating heat sources. The efficiency of the fin and the heat flow through the base of the fin are determined. It is shown that energy release in the fin increases its efficiency in comparison with the efficiency of the fin in the absence of energy release. There is also a decrease in the heat flow in the presence of energy release in the fin. The restriction on the values of energy release in the fin is found as condition for the applicability of the finning. The fin efficiency must be less than one. If the efficiency exceeds one, the fin plays the opposite role: the flow is directed in the reverse side. To increase the build-up coefficient of the surface, tend to reduce the distance between the fins. There is a limit to such reduction. Theoretically, the distance between the fins should be at least double the maximum thickness of the boundary layer. As experience shows, this distance can be reduced to about one thickness. An approach to achieve the largest build-up coefficient at finning is described in the article.