Novel micro heat pipe

摘要

With the development of miniaturized and high power electronic devices in recent years, electronic heat dissipating apparatus have become important. The concept of micro heat pipe (MHP) was first proposed in 1984 with the application background of electronic cooling. Since that time, numerous theoretical analysis and experimental tests were proposed, and most of cross section in the micro heat pipe is either rectangular or triangular. But the capillarity of these grooves is low, and restricts the heat transfer limitation. In this study, star grooves MHP and rhombus grooves MHP were fabricated. Heat transfer performance of micro heat pipe was enhanced due to the better capillarity provided by more acute angles and micro gaps. Star grooves MHP and rhombus grooves MHP fabricated by bulk micro machining on 4-inch (100) silicon wafers. Finally, micro heat pipe structure was bonded by employed eutectic bonding technique. Testing has been conducted to evaluate the performance over a range of working fluid volume, heat fluxes. We glue heater on the evaporator section of the heat pipe, infuse cold water through a copper pipe in the condenser section, and paste K-type thermocouples on the micro heat pipe in the direction of the length. Then we join the thermocouples to a data acquisition system and adopt Fourier's Law to calculate effective thermal conductivity. The best thermal conductivities of star grooves MHP and rhombus grooves MHP are 277.9 W/mK and 289.4 W/mK, respectively.