The thermal management requirement of the servers for data centers has become an urgent issue to be addressed. The two-phase compact thermosyphon has been one of the highly-efficient passive cooling devices to solve heat dissipation problems. In this study, compact thermosyphons with different heights (20 mm, 25 mm, and 50 mm) and filling ratios (25 % − 75 %) were investigated. The corresponding boiling curves and thermal performance were analyzed. Thermal resistance was defined to evaluate the thermal performance in the thermosyphon system. The experimental results illustrate that the reduction in height significantly influences the thermal behaviors of the compact thermosyphon. For the 20 mm height case, the bubble adheres to the condensation surface for a longer time compared with the other cases, which increases the entire bubble growth period. Boiling curves of compact thermosyphons with different heights and filling ratios exhibit distinct characteristics. The heat flux on the boiling surface (q_b) with 20 mm height at the low filling ratio (FR = 25 %) is 68.2 % of that with the 50 mm height, indicating the reduced boiling intensity. Both the delayed onset of boiling (ONB) and bubble films of large areas on the condensation surface are generated at FR = 75 % case with 20 mm height, which weakens the phase change heat transfer. For the 50 mm height case, a medium filling ratio and lower input heat flux provide the optimized performance (0.36 K·W⁻¹ of the thermal resistance). For the compact thermosyphon with lower height, low and medium filling ratios are preferred to minimize the deterioration of thermal performance. The outcomes are hoped to provide references for the optimal design and operation of the compact thermosyphon applied in the areas of thermal management and energy conservation.

数据中心服务器的热管理要求已成为亟待解决的问题。两相紧凑型热虹吸管已成为解决散热问题的高效无源冷却装置之一。在本研究中，研究了不同高度（20 毫米、25 毫米和 50 毫米）和填充率（25% – 75%）的紧凑型热虹吸管。分析了相应的沸腾曲线和热性能。定义热阻是为了评估热虹吸系统的热性能。实验结果表明，高度的降低显着影响紧凑型热虹吸管的热行为。对于20毫米高度的情况，与其他情况相比，气泡粘附在冷凝表面的时间更长，这增加了整个气泡的生长周期。不同高度和填充率的紧凑型热虹吸管的沸腾曲线表现出不同的特征。低填充率（FR=25%）时，20mm高度的沸腾表面热通量（q _b ）是50mm高度的68.2%，沸腾强度降低。在FR=75%、高度为20mm的情况下，延迟沸腾（ONB）和冷凝表面大面积的气泡膜都会产生，削弱了相变传热。对于 50 mm 高度的情况，中等填充率和较低的输入热通量提供了优化的性能（热阻为 0.36 K·W ⁻¹ ）。对于高度较低的紧凑型热虹吸管，优选低填充率和中等填充率，以尽量减少热性能的恶化。 研究结果希望为热管理和节能领域应用的紧凑型热虹吸管的优化设计和运行提供参考。