INTERNATIONAL ENERGY JOURNAL

Volume 22, No. 03, Month SEPTEMBER, Year 2022, Pages 195 - 214

Numerical simulation of cylindrical heat pipe using al2o3-water nanofluid as the working fluid

Narong Pooyoo, Sivanappan Kumar

Abstract Download PDF

This research was aimed to study the transport and thermal characteristics in a cylindrical heat pipe using Al2O3-water nano fluid. Maxwell-Garnett, Hamilton and Crosser, Jang and Choi, Chon et al. and Sitprasert et al. models were used to determine the thermal conductivity. The non-Darcian transport approach was used to determine the nanofluid flow in the liquid-wick section, while the mass flow rate was used to describe the fluid flow at liquid-vapor interface. The non-linear algebraic equations from finite volume method discretization were solved by iterative segregation method and the SIMPLEC algorithm. The numerical simulation results of axial outer wall temperature, centerline pressure, velocity magnitude and nanofluid recirculation were found to be in good agreement with the values obtained for the cylindrical heat pipe operation and earlier studies. The results indicate that alumina oxide in 20 nm mixed with water can reduce the thermal resistance of the cylindrical heat pipe by 5.7% in Maxwell-Garnett model and Hamilton and Crosser model; 36% in Jang and Choi model; 3.7% in Chon et al. model; 12.1% in Sitprasert et al. model; and 21.8% in Yu and Choi model compared to pure water. The simulation result shows that the use of Al2O3-water nanofluid increases the effective thermal conductivity in all models. Besides, the evaporator and condenser heat transfer coefficients are found to increase in models compared to that of pure water.

Keywords

Al2O3-water nanofluid; Cylindrical heat pipe; Single phase model; Thermal conductivity; Thermal resistance

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