A FEASIBILITY STUDY OF APPLYING PULSATING HEAT PIPE IN HEAT SINK

An experimental investigation was carried out for the feasibility of applying pulsating heat pipe (PHP) in processor unit cooling. Copper tubes with an external diameter of 2.5 mm and inner diameter of 1.3 mm were used for PHP manufacturing. The heat transport characteristics of the PHP were explored. It was proved that PHP is promising to use in handling high-power dissipation. The thermal performance of PHPs in different structures (U-shaped, L-shaped, and flat-shaped) were tested and the U-shaped PHP (where two ends are bent as a condensation section with a central evaporation section) was considered to be the best one. Therefore, the U-shaped PHP was chosen to develop a thermal module−a new type of PHP heat sink design. Compared to a conventional finned heat sink design and a heat pipe embedded solution, the advantages of the new PHP heat sink design became obvious under high-power heating, and kept a lower and stable thermal resistance. Its thermal resistance was equal to 0.68 K/W, when the heating power was 200 W and the heating contact area was 14 × 14 mm. Judging from the inflection point of the temperature curve of the PHP heat sink, it was considered that a larger proportion of heat was transported by latent heat.