NUMERICAL SIMULATION OF THE EFFECTS OF VOLUME FRACTION AND NANOPARTICLE DIAMETER ONNANOFLUID HEAT TRANSFER IN A MICRO HEAT PIPE USING CFD

Abstract

In this study, the heat transfer of nanofluid convection in a micro heat pipe has been comprehensively investigated numerically using ANSYS Fluent software. The simulation was performed based on the finite volume method and considering turbulent flow, and the effect of two key parameters, including the volume percentage of nanoparticles and the diameter of nanoparticles on the temperature field, heat transfer coefficient, and Nusselt number, was analyzed. The validation of the numerical model with reliable data available in the literature indicates the high accuracy of the simulation results. The results showed that increasing the volume percentage of nanofluid causes a significant decrease in the wall surface temperature, a more uniform temperature distribution, and a significant increase in the heat transfer coefficient and Nusselt number. Also, decreasing the diameter of the nanoparticle plays a significant role in enhancing heat transfer due to the increase in specific surface area and intensification of Brownian motion. Analysis of temperature contours and thermal profiles showed that nanofluid causes thinning of the thermal boundary layer and an increase in the temperature gradient in the vicinity of the wall. On the other hand, an excessive increase in the volume fraction leads to increased viscosity and pressure drop, making an optimal range necessary. The results of this study confirm that nanofluids can be used as an efficient solution to improve the thermal performance of micro-exchangers and compact cooling systems. These achievements have wide applications in cooling of electronic equipment, energy systems, micro-heat exchangers, and advanced technologies.