A new-type of loop heat pipe (LHP)

which is enhanced by the pressure head due to evaporation

was proposed and studied. Its wick was separated from the heating surface and a steam chamber was formed in which the phase change of the working fluid occurs and the pressure head due to evaporation can be effectively used. In the experiment

different charging ratios were considered to explore the operation characteristic. Results showed that the temperature oscillation occurred when the charging ratio was high (60%). Furthermore

higher charging ratios resulted in higher operating temperatures; namely

101.9 ℃

102.4 ℃

and 107.9 ℃ corresponding to 55%

60%

and 70% of charging ratio

respectively. In addition

the specific operating model

a dropping-evaporation process

was found through the visual observation of the evaporator when the charging ratio was 55%. The vapor-liquid interface moved downward on the surface of the wick and finally

the liquid dropped on the heating surface

illustrating the specific operation process for this kind of LHP. If the period is defined as the time needed to complete the dropping and evaporation cycle for the working fluid

the cycle time was 120 s when the head load was 55 W.