G. A. Sheikhzadeh - Department of Thermo-fluids, faculty of Mechanical Engineering and Energy Research Institute, University of Kashan, Kashan, Iran
M. M. Fakhari - Department of Mechanical Engineering, Engineering Faculty, University of Birjand, Birjand, Iran.
H. Khorasanizadeh - Department of Thermo-fluids, faculty of Mechanical Engineering and Energy Research Institute, University of Kashan, Kashan, Iran

In this experimental study, heat transfer of a coolant nanofluid, obtained by adding alumina nanoparticles to Ethylene Glycol-water (۶۰:۴۰ by mass), in a car radiator has been investigated. For this purpose, an experimental setup has been designed and constructed. Firstly, to investigate the accuracy of the results, the experiments have been done for the base fluid. Then the experiments have been performed for the nanofluid with different nanoparticles volume fractions of ۰.۰۰۳, ۰.۰۰۶, ۰.۰۰۹ and ۰.۰۱۲. To ensure laminar flow regime three coolant flow rates of ۹, ۱۱ and ۱۳ lit/min have been tested. The thermophysical properties have been calculated using the recently presented temperature dependent models in the literature. According to the results, both the convective heat transfer coefficient and Nusselt number increase (about ۹%) with increasing the coolant flow rate. Also, convective heat transfer coefficient increases with increasing the nanoparticles volume fraction. Although Nusselt number decreases when nanofluid is utilized, it enhances as the nanoparticles volume fraction increases. Based on the experimental results obtained, A new empirical correlation has been developed for average Nusselt number of Al۲O۳-EG-water nanofluid in developing region of flat tubes of car radiator for laminar flow and its maximum error is ۳%.

Experimental study, Car radiator, Al۲O۳, Ethylene Glycol, water nanofluid, Nusselt number