The increasing demand of nanofluids in industrial applications has led to increased attention from many researchers. In this paper, heat transfer enhancement using TiO2 and SiO2 nanopowders suspended in pure water is presented. The test setup includes a car radiator, and the effects on heat transfer enhancement under the operating conditions are analyzed under laminar flow conditions. The volume flow rate, inlet temperature and nanofluid volume concentration are in the range of 2–۸ LPM, 60–۸۰ °C and 1–۲% respectively. The results showed that the Nusselt number increased with volume flow rate and slightly increased with inlet temperature and nanofluid volume concentration. The regression equation for input (volume flow rate, inlet temperature and nanofluid volume concentration) and response (Nusselt number) was found. The results of the analysis indicated that significant input parameters to enhance heat transfer with car radiator. These experimental results were found to be in good agreement with other researchers’ data, with a deviation of only approximately 4%.

Introduction

The main reason solid particles less than 100 nm are added to a liquid is to improve its thermal properties; this new fluid is then defined as a nanofluid. Solid metallic or nonmetallic materials dispersed in base fluids such as water, ethylene glycol and glycerol have become a topic of interest in recent years [1–۷]. There are various applications of thermo fluid systems, including automotive cooling systems [8,9]. Base fluids (water, ethylene glycol and glycerol) have been used as conventional coolants in an automobile radiator for many years; however, these offered low thermal conductivity, which has prompted researchers to find fluids that offer higher thermal conductivity compared to that of conventional coolants. This resulted in nanofluids being used instead of these base fluids [10,11]. Forced convection heat transfer to cool circulating water from an automobile radiator was carried out by Peyghambarzadeh et al. [12]. The effects of different amounts of Al2O3 nanoparticles on the heat transfer performance of the automobile radiator were determined experimentally. The range of flowrate changed from 2 to 6 LPM with the changing inlet temperature of the fluid for all the experiments. The results showed a 40% increase in heat transfer by nanofluids compared to water. A numerical study of laminar heat transfer (CuO and Al2O3) with ethylene glycol and water inside the flat tube of a car radiator was carried out by Vajjha et al. [13]