1888 words - 8 pages

In this study, the steady-state natural convection heat transfer from vertical rectangular fins extending perpendicularly from vertical rectangular base was investigated experimentally. The effects of perforations and base-to-ambient temperature difference on the heat transfer performance of fin arrays were observed and optimum value of perforation is suggested. The experimental set-up was employed during experiments in order to take measurements from 4 different fin configurations. The base and the ambient temperatures were measured in order to evaluate the heat transfer rate from fin arrays.

The results of experiments have shown that the convection heat transfer rate from fin arrays depends on all percentage of perforation and base-to-ambient temperature difference. The effect of these parameters was also examined, and it was realized that for a given base-to-ambient temperature difference, the convective heat transfer rate from the fin array is maximum for 30% perforated fin array.

KeyWords: Perforation, Fins, Steady state, Natural convection

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1.Introduction:

While we are operating many of the engineering systems there is a major problem of generation of heat. This generated heat can play a role in the failure of the system due to overheating. This generatedheat in a system should be dissipated in the surrounding so as to maintain the system at its recommended working temperatures.Due to this the system can be operated with good efficiency. In modern electronic systemsthe packaging density of circuits is much higher; therefore the problem of heating is serious in this case. In order to overcome this problem, thermal systems with effective emitters as fins are desirable [1].

If we want to achieve the required heat dissipation rate, with the least amount of material, the combination of geometry and orientation of the fins should be optimum. Among these variations of geometry, rectangular fins are the most commonly used fin geometry because of their simple construction, least cost and effective cooling capacity. There are two types of orientations with regards to rectangular fin configurations, horizontally based vertical fins and vertically based vertical fins, have been more commonly used in the applications. However, the horizontal orientation is not preferable because of its relatively poorer ability to dissipate heat [2].

The basic equation of convection heat losses is given by:

"Q" _"c" "=hA∆T" 1.1

As seen from Eq. (1.1), the rate of heat dissipation from the surface can be enhanced either by increasing the heat transfer coefficient, h or by increasing the surface area, A. The value of h can be enhanced by using proper conditions of forced flow over the required surface. Although the forced convection is efficient, it requires an extra spacefor fan...

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