This research aims to study the capillary pumped loop (CPL) pipe line temperature distributions. A simple axial heat transfer method was developed to predict the pipeline temperature from evaporator outlet to evaporator inlet.

CPL is a high efficiency two-phase heat transfer device. Since it does not need any other mechanical force such as pump, furthermore, it might be used to do the thermal management of high power electronic component such as spacecraft, notebook and computer servers. It is a cyclic circulation pumped by capillary force, and this force is generated from the fine porous structure in evaporator. A novel semi-arc porous evaporator to CPL in 1U server was designed on the ground with a horizontal position and scale down the whole device to the miniature size.

Reservoir was designed and set up in the liquid head. The influence of reservoir upon thermal resistance was also analyzed. The thermal resistance for CPL with reservoir could keep almost a constant value from low to high thermal loading. On the contrary, the thermal resistance became stable at higher power when the CPL without reservoir. In addition, the thermal resistance of CPL with reservoir was much lower than that without reservoir. It was indicated that reservoir was helpful to maintain a stable CPL performance.

From the experimental results, the CPL could remove heat 110W in steady state and keep the heat source temperature about 80oC. At theoretical results, condenser inlet temperature; condenser outlet temperature; condenser base temperature; fin number demand; fin heat removal ability and mass flow rate could be calculated from the theoretical model. A good agreement between the theoretical results and experimental values had been achieved.

In summary, the CPL has already been turned into the electronics cooling device of new generation. Semi-arc inner evaporator structure provides designer a new design direction and an axial heat transfer method allow designer more freedom.

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