Numerical Simulation of Graphene-Nanoplatelet Nanofluid Convection in Millimeter-Sized Automotive Radiator

Abstract

The depletion of fossil fuels and environmental considerations in transportation sector motivate the researchers to enhance the efficiency and performance of the automotive systems. However, the poor thermal performance of conventional coolant poses a limitation in the development of energy-efficient vehicle due to the cooling constraint. In the present study, a comprehensive numerical study is conducted to scrutinize the convective performance of graphene nanoplatelets (GnP) nanofluid in millimeter-sized automotive radiator, aiming to enhance the understandings on the underlying physical significance of the suspension of graphene-based nanoparticle in water for the performance enhancement of automotive radiator. The temperature-dependent thermophysical properties of GnP-water nanofluid is predicted via existing correlations, while a modified viscosity correlation is developed. ANSYS Fluent is employed in the present numerical simulation to investigate the effects of various pertinent parameters such as Reynolds number, nanoparticles aspect ratio, tube aspect ratio and tube hydraulic diameter on the heat transfer performance of the radiator. Double precision and second-order upwind scheme with inclusion of viscous heating, and convergent criteria of 10˗6 are adopted for the present simulation. It is observed that the convective performance of the radiator is significantly enhanced by increasing Reynolds number and nanoparticle volume fraction while decreasing the aspect ratios of nanoparticle and radiator tube, with an enhancement rate as much as 1816%. Therefore, it is evident that the suspension of GnP intensifies the heat transfer performance of millimeter-sized automotive radiator, which could possibly lead to a more efficient radiator that is smaller and lighter.