Heat transfer characteristics of micro heat pipe

Abstract

Overheating of integrated circuit (Ie), microchip etc. is a potential threat to these electronic components. It is very important to facilitate optimum cooling of electronic components in a smaller electronic device because integrated circuit lifetime depends on it. An increasing market demand on powerful gadgets in smaller and smaller cabinets creates a trade off situation: either to enlarge the package to accept additional cooling or to sacrifice IC lifetime. This is a great challenge in thermal design management. Among other cooling techniques heat pipe emerges as the most appropriate technology and cost effective thermal design solution due to its excellent heat transfer capability, high efficiency and its structural simplicity. Due to the space constraint in most of personal computers and telecommunication devices, the size of heat pipes has to be carefully decided. Thus application of micro heat pipe (MHP) has been extended gradually. So investigation on MHP is indispensable for further development and improvement of its performance. An experimental study has been performed to investigate the heat transfer characteristics of micro heat pipe (MHP) of circular geometry having inner diameter of 1.8 mm and length of 150 mm. The experimental parameters are inclination angle, coolant flow rate, working fluid and heat input. Taking acetone, ethanol and methanol as working fluid, heat transfer characteristics are determined experimentally for different inclination angle and different coolant flow rate at different heat input. An analysis of the experimental data gives following findings: Coolant flow rate has an insignificant effect on the performance of MHP. Performance of MHP depends upon angle of inclination. Better performance is found for an inclination angle of 700. Heat input has significant effect on the performance of MHP. It is found that overall heat transfer coefficient is higher for higher heat input. Finally, it is observed that for the same heat input and inclination angle MHP with acetone as working fluid performs better. An empirical correlation has also been developed which correlates all the experimental data within o!o 7% error.