Heat transfer characteristics of miniature heat pipes

Abstract

During last twenty years, component density on integrated circuits has grown from about six thousand transistors on the Intel 8080 microprocessor to over five million transistors on a similar-sized Intel P6 microprocessor. Power and component densities on these integrated circuits have required the development of innovative cooling methods. Miniature heat pipes (MHPs) appear promising for use in microelectronics cooling. An experimental study has been performed to understand the heat transfer performance of Miniature Heat Pipes (L=150 mm) having diameter of 3,5 and 6 mm, which can be applied for cooling solution of electronics equipment such as the notebook PC, CPU etc. The experimental parameters are inclination, diameter of the heat pipe, coolant flow rate and working fluid. Taking ethanol, methanol, acetone as working fluid, heat transfer characteristics are determined experimentally for all diameter tubes, based on the principle of phase change at different inclination angle and different flow rate of water coolant. An analysis of the experimental data gives the following findings: The wall surface temperature of heating section decreases with increase of inclination of MHP. There is no significant effect of inclination angle on thermal resistance and overall heat transfer coefficient. The heat transfer rate increases with the increase of diameter and input power. Overall heat transfer coefficient of the MHP is found to be maximum for ethanol working fluid.