The thermal performance of a double tube two-phase closed thermosyphon (DTTPCT) using alumina nanofluid as working fluid in startup, steady state and shut down modes has been experimentally and theoretically evaluated. Gamma-Alumina (γ-Al₂O₃) nanoparticles with size of 40 nm were well dispersed, prepared and stabilized in distilled water base fluid at different particle concentrations.The axial wall temperature distribution, the nanofluid temperature along the thermosyphon, the thermal conductivity and overall heat transfer coefficient were investigated to propose the best combination of parameters by varying parameters such as concentration of nanoparticles, heat load on heat pipe. The effect of nanofluid volume fraction of 0.5%, 1.0%, 1.5%, and 2.0% with heat load of 500 W, 750 W, 1000 W and 1250 W on the overall thermal conductivity of the heat pipe were studied to evaluate the optimal thermal performance. The results indicate that the DTTPCT filled with alumina nanofluid in 2% volume fraction yields higher thermal performance when it is operated at 1000 W heat load. The experimental results show that the optimal thermal performance of TPCT filled with Al₂O₃/water nanofluid at a heat load of 1000 W is 3 times better than that of pipes using distilled water as the working fluid. Theoretical model describing both thermal performance and phase flow of the DTTPCT has been compared with the experimental results at start-up, steady-state and shut-down modes.

已经通过实验和理论评估了使用氧化铝纳米流体作为工作流体的双管两相封闭式热虹吸管（DTTPCT）在启动，稳态和关闭模式下的热性能。γ-氧化铝（γ-Al系₂ ö ₃）在不同浓度的蒸馏水基础液中充分分散，制备和稳定了尺寸为40 nm的纳米颗粒。研究了轴向壁温分布，沿热虹吸管的纳米流体温度，导热系数和总传热系数，提出了以下建议：通过改变参数（例如纳米颗粒的浓度，热管上的热负荷）来实现参数的最佳组合。研究了纳米流体体积分数分别为0.5％，1.0％，1.5％和2.0％以及500 W，750 W，1000 W和1250 W的热负荷对热管总导热率的影响，以评估最佳导热性能。结果表明，当以1000 W热负荷运行时，以2％体积分数填充了氧化铝纳米流体的DTTPCT会产生更高的热性能。热负荷为1000 W的₂ O ₃ /水纳米流体比使用蒸馏水作为工作流体的管道要好3倍。描述了DTTPCT的热性能和相流的理论模型已与启动，稳态和关闭模式下的实验结果进行了比较。