This study investigates the effect of gravity on the flow pattern and thermal efficiency of a single-loop oscillatory heat pipe. To simulate the influence of gravity, the deployment angles of the mechanism are varied (30°, 45°, 60°, and 90°). OpenFoam software is implemented to model boiling and condensation in the oscillating heat pipe, utilizing the volume of fluid (VOF) method. The evaporator is supplied with 55.5 W of heat power, the condenser wall temperature is maintained at 300 K, and the filling ratio of heat transfer fluid (water) is 40%. The findings revealed that decrease in gravitational force results in the thermal resistance be increased and the thermal performance of heat pipes be diminished. Expectedly, the best thermal performance in the oscillating heat pipe is observed in vertical mode, however, this study also examines the influence of reduced gravity. The simulation results show that the bubble pattern is first initiated by the bubble nucleation at the start of the heating process. Consequently, by bubble coalescence the slug and annular regimes can be observed. The phenomenological analysis of the dissolution, bubble coalescence, growth, and contraction observed in this study are discussed.

本研究研究了重力对单回路振荡热管的流动模式和热效率的影响。为了模拟重力的影响，机构的展开角度是不同的（30°、45°、60°和90°）。 OpenFoam 软件利用流体体积 (VOF) 方法对振荡热管中的沸腾和冷凝进行建模。蒸发器提供55.5 W热功率，冷凝器壁温保持在300 K，传热流体（水）填充率为40%。研究结果表明，重力的减小会导致热阻增大，热管的热性能下降。预期，振荡热管的最佳热性能是在垂直模式下观察到的，但是，这项研究还检查了重力减小的影响。模拟结果表明，气泡图案首先是由加热过程开始时气泡成核引发的。因此，通过气泡聚结，可以观察到段塞和环形状态。讨论了本研究中观察到的溶解、气泡合并、生长和收缩的现象学分析。