Thermal Spreading with Flat-Plate Oscillating Heat Pipes

摘要

The thermal performance of a flat-plate oscillating heat pipe operating as a heat spreader was experimentally investigated. The copper flat-plate oscillating heat pipe had overall dimensions of 101.6 x 101.6 x 3.18 mm(3), possessed two layers of 1.02 x 1.02 mm(2) minichannels, and was charged with acetone to a filling ratio of approximately 80%. The flat-plate oscillating heat pipe was centrally heated with a 9 cm(2) square heat source and had a copper pin-fin heat sink attached to its opposite side for crossflowing air at speeds of either 1, 2, or 3 m/s. The results clearly indicated that the flat-plate oscillating heat pipe is capable of operating in the thermal spreading mode, providing for a 10-15% reduction in total thermal resistance (relative to pure copper) and managing heat inputs up to 230 W (similar to 25 W/cm(2)) with the maximum surface temperature not exceeding 100 degrees C. In addition, the temperature uniformity of the heat sink was greater when attached to the flat-plate oscillating heat pipe, especially for lower Reynolds numbers (airspeeds). A critical heat input was required to initiate the flat-plate oscillating heat pipe, and this heat input increased with Reynolds number. This study further confirms the heating mode directly affects the heat transfer performance of a flat-plate oscillating heat pipe.