LAUSR

Abstract An experimental investigation on the effect of cooling air velocities, operating orientations and heat inputs on a three-dimensional oscillating heat pipe (3D-OHP) was studied seriously. The 3D-OHP had dimensions of 90 mm × 61 mm × 150 mm, 6 total turns, 3 layers along width direction and 4 layers along length direction. Unlike traditional OHP designs, this new three-dimensional multi-layer design allows for different working conditions in thermal management such as multi-heat source cooling and higher heating fluxes cooling. The thermal performance of the 3D-OHP was studied by testing temperature variation measured at various heat inputs under different cooling air velocities and operating orientations. The results indicated both the cooling air velocities and operating orientation significantly affect the start-up, oscillation and dry-out of the 3D-OHP. The start-up temperature decreased and the dry-out limit increased with the increase of cooling air velocities and the decrease of the operating angle. Difference of thermal resistance in each layer along different directions was also calculated. It was found that only operating orientation had remarkable influence on thermal resistance of different layers along length direction. The difference between the thermal resistance of the skin layer and the inner layer increased with the decrease of operating angle.