Experimental study on steady-state performance of an axial grooved heat pipe under rotational condition

Abstract

This study explores the performance optimization of grooved heat pipes under rotational conditions, focusing on both straight and curved designs. To address the challenges posed by centrifugal forces in rotating systems, we designed and tested a conventional straight grooved heat pipe and a novel curved grooved heat pipe with a variable curvature structure. Experiments were conducted across a range of rotational speeds (0–20 rpm), heat loads (30 W-300 W) and loading methods (heat load before rotation and heat load after rotation) to evaluate the operating performance of both grooved heat pipes. The results indicate that the straight grooved heat pipe struggled to maintain efficiency under rotational conditions, as centrifugal forces caused fluid to accumulate at both ends, leading to higher operating temperatures and reduced heat transfer efficiency. At the case of 20 rpm with a heat load of 110 W, the temperature difference exceeded 25 °C, highlighting the limitations of the straight design in such environments. In contrast, the curved grooved heat pipe effectively mitigated the impact of centrifugal forces. Its design reduced liquid accumulation in the condenser section, maintained beneficial acceleration effects in the evaporator section, and improved overall heat transfer performance. Specifically, at 20 rpm, the curved pipe successfully transferred over 300 W with a temperature difference not exceeding 5 °C, demonstrating its superior performance. However, at higher rotational speeds and lower power levels, the curved design also showed some limitations, as excessive fluid accumulation in the evaporator section led to a shift in the evaporation site, increased thermal resistance, and a certain degree of superheating. These findings highlight the potential of the variable curvature design in improving the efficiency of grooved heat pipes under rotational conditions. This work advances the understanding of fluid dynamics and heat transfer mechanisms in such systems, offering insights that could inform the design of more efficient heat pipes for rotating applications.