Experiments and Comparisons of Three Miniature Heat Pipes' Thermal Performance

摘要

The heat transfer capacities and heat transfer coefficients of three different types of miniature heat pipes (MHP) were tested and compared. The three cylindrical miniature copper-water heat pipes, including one smooth pipe, one mesh wicked pipe and a new inner helical grooved pipe of a similar hydraulic diameter of about 4 mm, were separately tested under different heat inputs, working temperatures and inclination angles. As the experimental results indicated, compared with the smooth pipe, the mesh wick pipe and inner helical grooved pipe are both with better heat transfer capacities and higher heat transfer coefficients in evaporator section under the same working condition. The inner helical grooved pipe had a similar trend of maximum heat transfer rate in the working temperature range from 43°C to 80°C as the smooth pipe, however about 40% to 240% above the smooth pipe. In the section of evaporator, it is also revealed that the suggested pipe had an about 60% to 85% better heat transfer coefficient performance over the smooth pipe at the same working temperature. Among the three MHPs tested, the mesh wick pipe brought forward the best performance, especially compared with the smooth pipe. Together with the advantage of easy fabrication, the inner helical grooved pipe is suitable for applications in electronic products such as notebook PCs.