Thermophysical Characterization of Nanofluids for Enhanced Performance in Cooling Circuits

The growing demand for efficient thermal management systems in both industrial and automotive sectors has driven substantial interest in nanofluids - engineered colloidal suspensions of nanoparticles in conventional fluids. By tailoring the thermal properties of the base fluids through nanoparticle dispersion, nanofluids offer the potential to substantially improve heat transfer performance, thereby increasing system efficiency, reducing the weight and volume of cooling systems, and contributing to energy savings and environmental sustainability. This study presents a comprehensive experimental investigation on the thermophysical properties of three environmentally friendly nanofluids: one water-based formulation, designed for high-performance engine cooling in racing vehicles, and two based on a 60/40 wt% water-glycerol mixture, intended for general-purpose closed-loop cooling applications. Thermal conductivity measurements were conducted using a Hot Disk apparatus with a declared accuracy of 5% over the temperature range 338.15 K to 353.15 K. In the same temperature range, the specific heat capacity was determined via a MicroCalvet differential scanning calorimeter, with an instrument uncertainty of 2%. Additionally, the convective heat transfer coefficient was evaluated using a custom-built test rig under controlled thermal conditions. All three nanofluid samples exhibited improved thermal conductivity, specific heat, and convective heat transfer coefficients compared to their respective base fluids. These results confirm the potential of nanofluids to enhance the efficiency of thermal management systems and support their future implementation in advanced cooling technologies.