The rapid advancement of 5G technology has significantly accelerated the progression of mobile devices, promoting the evolution of electronic products such as smartphones, tablet computers, and virtual reality (VR) and augmented reality (AR) eyewear towards an increasingly foldable design. However, due to the inherent constraints of spatial and structural characteristics, conventional thermal management solutions are no longer adequate to meet the performance requirements of these foldable devices. Therefore, it is imperative to develop efficient thermal management solutions that are compatible with the cross-hinge structures within chip design. This study proposes and fabricates a novel ultra-thin flexible loop heat pipe (UFLHP) with a thickness of merely 0.7 mm to address the heat transfer challenges posed by cross-hinge designs. By utilizing powder sintering and wire cutting techniques, an innovative approach has been developed for fabricating a metallic powder wick with a thickness of 0.4 mm. During the experiments, ethanol was employed as the working fluid to systematically investigate the effects of thermal loading, tilt angle, and bending angle on the steady-state heat transfer performance of the UFLHP. The experimental results indicate that the maximum heat flux density of the UFLHP reaches 5 W/cm2. Under this heat flux density, the evaporator temperature of the UFLHP attains 72.15 °C, while the thermal resistance is measured at 2.48 K/W, resulting in an effective thermal conductivity of 10,273.27 W/(m·K). The tilt angle has a beneficial effect on the UFLHP’s performance under gravitational influence, while the bending angle adversely affects its performance due to increased flow resistance. This research provides a feasible solution for the heat dissipation challenges in foldable electronic devices.

中文翻译：

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弯曲热量：创新的超薄柔性回路热管，可增强移动设备冷却效果


5G 技术的快速发展显着加速了移动设备的发展，推动了智能手机、平板电脑以及虚拟现实 （VR） 和增强现实 （AR） 眼镜等电子产品向越来越可折叠的设计发展。然而，由于空间和结构特性的固有限制，传统的热管理解决方案已不足以满足这些可折叠设备的性能要求。因此，必须开发与芯片设计中的交叉铰链结构兼容的高效热管理解决方案。本研究提出并制造了一种厚度仅为 0.7 mm 的新型超薄柔性回路热管 （UFLHP），以解决交叉铰链设计带来的传热挑战。通过利用粉末烧结和线切割技术，已经开发了一种创新方法来制造厚度为 0.4 mm 的金属粉末吸芯。在实验过程中，以乙醇为工作流体，系统研究了热负荷、倾斜角和弯曲角对 UFLHP 稳态传热性能的影响。实验结果表明，UFLHP 的最大热通量密度达到 5 W/cm2。在此热通量密度下，UFLHP 的蒸发器温度达到 72.15 °C，而热阻测量为 2.48 K/W，有效导热系数为 10,273.27 W/（m·K）。倾斜角对 UFLHP 在重力影响下的性能有有利影响，而弯曲角则由于流动阻力增加而对其性能产生不利影响。 本研究为可折叠电子设备的散热挑战提供了一种可行的解决方案。