A heat pipe, which contains evaporator, adiabatic, and condenser, is a simple device with proper heat transfer rate and a little heat loss, without any moving parts. In this study, the effects of length of the three mentioned sections of heat pipe were investigated through introducing the ratio of adiabatic length to the condenser length or evaporator length as aspect ratio (AR), filling ratio of working fluid, and heat load on the thermal performance of a thermosyphon heat pipe by combining computational fluid dynamics (CFD) and design of experiment (DOE). Optimum conditions were obtained using DOE. Prior to determining the optimum conditions, the heat pipe was simulated using volume of fluid model through solving the governing equations of mass, momentum, and energy for evaporation and condensation phenomena by finite volume method. The results were confirmed by comparing the 2D CFD simulation results with the experimental data. The purpose of this research was to find the optimal lengths of different parts. The results showed that the averaged optimum values for the above mentioned parameters (AR, heat load, and filling ratio) were 0.8325, 246 W, and 85%, respectively. In total, thermal performance of the heat pipe was improved for lower adiabatic zone length and higher values of heat load and filling ratio.

热管由蒸发器、绝热器和冷凝器组成，是一种简单的装置，传热速率合适，热损失小，没有任何运动部件。在本研究中，通过引入绝热长度与冷凝器长度或蒸发器长度之比作为纵横比 (AR)、工质填充率和热负荷，研究了上述三个热管段的长度对热管的影响。通过结合计算流体动力学 (CFD) 和实验设计 (DOE) 来研究热虹吸管的热性能。使用 DOE 获得了最佳条件。在确定最佳条件之前，通过有限体积法求解蒸发和冷凝现象的质量、动量和能量的控制方程，使用流体体积模型对热管进行模拟。通过将 2D CFD 模拟结果与实验数据进行比较，证实了该结果。这项研究的目的是找到不同部分的最佳长度。结果表明，上述参数（AR、热负荷和填充率）的平均最佳值分别为 0.8325、246 W 和 85%。总的来说，热管的热性能因绝热区长度更短和热负荷和填充率更高而得到改善。