Thermal performance of a large-diameter thin flattened heat pipe with novel composite wick structure

Abstract

Flattening large-diameter cylindrical heat pipes to fabricate thin heat pipes can significantly improve their heat transfer performance in theory, but their appropriate wick structures and thermal performance are still unclear. In this work, a novel composite wick structure sintered from spiral woven mesh and orthogonal woven mesh was developed for large-diameter thin flattened heat pipes. Their diameter and thickness were 8 and 1.0 mm, respectively. Seven types of wick structures for the experimental heat pipes were designed to investigate the effects of the length and position of the orthogonal woven mesh on the thermal performance. The results indicated that based on the spiral woven mesh, sintering the orthogonal woven mesh in the evaporator and adiabatic sections of the heat pipe can significantly improve the thermal performance. Compared with the single spiral woven mesh wick, the maximum heat transport capacity of the experimental heat pipe with optimal composite wick increased by 41.67%, and the evaporation and total thermal resistances decreased by 68.41% and 61.49%, respectively. This study provided very useful guidance for improving the thermal performance of the large-diameter thin flattened heat pipes for cooling laptops.

Keywords

• Heat pipe
• Wick
• Spiral woven mesh
• Orthogonal woven mesh
• Thermal performance