DEVELOPMENT AND EVALUATION OF A PLANAR HEAT PIPE FOR COOLING ELECTRONIC SYSTEMS

A planar heat pipe (rectangular cross section) was designed, built and tested using flexible electrical rubber heaters to provide the necessary heat. The device was constructed from 0.043” (0.1092 cm) copper sheet, with three layers of 100-mesh copper screen as a capillary wick. The dimensions of the planar heat pipe were 6 inches (15.24 cm) by 12 inches (30.48cm) by 3/4 inches (1,905 cm). Water was used as the working fluid. Steady state, and in once case, transient responses, were investigated. External axial temperature profiles for different applied powers and operating temperatures were measured. Operation of the device was stable and repeatable within a temperature range of 30° to 95°C; no temperature or pressure fluctuations were noted. The optimum amount of working fluid for a typical situation was obtained experimentally. Effects of air and amount of working fluid inside the planar heat pipe were investigated. The optimum amount of working fluid which was obtained experimentally was used throughout the remaining tests in this research. Effects of gravity, a wide range of operating temperature, Reynolds number at constant input power, and Reynolds number at constant operating temperature were investigated. The maximum heat transfer rate of the planar heat pipe was obtained experimentally and compared to it is theoretical value. Good agreement was obtained between the two values. © 1990, Taylor & Francis Group, LLC. All rights reserved.