Influence of vibration in enhancement of heat transfer rates from thin plannar fins

Abstract

The enhancement of heat transfer rates without an extension of heat removal surface area due to packaging and compactness is essential. This paper investigates the possibility of the enhancement of heat transfer rate from heat sink having thin planner fins by normal vibration. In this study; the heat sink was selected to be the personal computer heat sink as a test specimen. It has four similar quadrants; each quadrant has a definite number of thin planer fins. The specimen is heated by an electric heater at its bottom. A circular disc cam with an offset center is used to vibrate the specimen with different displacement amplitude and frequency. Temperature measurements for both the surface of the specimen and surrounding air were recorded and saved by using a data acquisition system at different sample times according to the vibration frequency. The effect of both vibration frequency and displacement amplitude on the enhancement of heat transfer rate was clarified. Deduced empirical correlation among Nusselt number, Strouhal number and Reynolds number was found. It was found that the normal vibration can enhance the heat transfer rate for the case study by about 85% rather than the steady flow case if both are having the same average velocity. In a comparison among the present investigation and those by the literature, the influence of vibration on heat transfer enhancement may be slightly greater than that of the pulsating flow.