Influence of the geometrical parameters and particle concentration levels of hybrid nanofluid on the thermal performance of axial grooved heat pipe

In the present study, a numerical model is developed to maximize the thermal performance of axial grooved heat pipe (AGHP) working on CeO₂ + MWCNT / water based hybrid nanofluid (HNF). The effects of a wide range of volume concentration (0.25%−1.50%) at different operating temperatures (55 ℃−75 ℃) are analyzed to maximize the thermal performance of AGHP. The current numerical work aims at finding the heat transport capacity, Q_max, and total thermal resistance, R_total, of AGHP with acceptable accuracy by validating it with the past experimental studies. It has been observed that the highest Q_max is achieved at 1.25% of the volume concentration of HNF for each operating temperature. The novel HNF based AGHP shows an enhancement of 61.27% in the heat transport capacity and a reduction of 30% in the total thermal resistance compared to the water-based AGHP. The study is further extended by incorporating the effects of geometrical parameters on AGHP's thermal performance. Three geometrical parameters are considered in this study, namely groove height (h_g), number of axial grooves (N), and their inclination angle (α). A total of 128 combinations of N, h_g, and α have been analyzed to optimize Q_max and R_total. The maximum thermal performance of AGHP is achieved at N = 28, h_g = 1.3 mm, and α = 76°, where the Q_max = 78.5 W and R_total = 0.054 °C/W.