Abstract
Effects of tube diameter (34mm, 22mm, 14mm) and inclination on performance of thermosiphon type heat pipe are investigated experimentally. Pure water and aqueous solution of surfactant (potassium oleate) are used as a working fluid. Then relation between inside flow and thermal resistance is studied. Thermal resistance of 22mm heat pipe is the lowest among the test heat pipes for both pure water and aqueous surfactant solution cases. When heat pipes are active in their operation and have lower thermal resistances, strong boiling that blows liquid working fluid to the condenser section is always happened. For tilt angle of 0°~75° from the vertical, the larger the tilt angle is, the lower the thermal resistance is under all experimental conditions. Thermal resistance of vertical 34mm heat pipe using surfactant solution (potassium oleate 300ppm) is reduced by about 60% at maximum under low cooling temperature and small heat transfer rate condition compared to that of pure water.
