Influence of the channel profile on the thermal resistance of closed-loop flat-plate oscillating heat pipe

The closed-loop flat-plate oscillating heat pipe (CL-FPOHP) is a new two-phase heat transfer device for an effective thermal management in different systems. A number of theoretical and experimental investigations have been carried out on the CL-FPOHP in the past decades after its invention. However, due to the operational mechanism of the CL-FPOHP, the effects of channel profile on the thermal resistance have not been completely revealed so far. This paper aims at discussing the thermal resistance and thermal conductivity by changing the shape and size of the CL-FPOHPs channel. The thermal resistances of the CL-FPOHPs were investigated by varying the channel shape from square to circular, channel sizes from 2 x 2 mm(2) to 5 x 5 mm(2), and heat load from 10 to 120 W. The pure copper was used to develop the CL-FPOHP and charged with the acetone with a charge ratio of 70%. The most suitable channel shape for the CL-FPOHP was found to be a square channel, and the most suitable channel size was observed to be 2 x 2 mm(2). The highest thermal conductivity of the CL-FPOHP reached to 2137 W/m degrees C.