A comprehensive experimental investigation of different nanofluids effective thermal conductivity

Abstract Nanofluids, renowned for their superior thermal conductivity relative to traditional fluids, have attracted considerable interest for their prospective applications in heat exchangers, cooling systems, and renewable energy technologies. Effective thermal conductivity has been determined for four distinct nanofluids such as silicon dioxide, cerium oxide, magnesium oxide and copper oxide at four different temperatures between 30 and 60 °C with intervals of 10 °C. Furthermore, four different volume percentages of nanoparticles have been chosen in the water-based base fluid, ranging from 0.5 to 2 percentages with increment of 0.5 percentages. There are various techniques to prepare the nanofluids and in the present study the ultrasonication technique has been adopted in the preparation of nanofluids. The aim of this study is to determine how the temperature and the volume percent variations of nanoparticles in the bass fluid influence the effective thermal conductivity. The effective thermal conductivity has been found to be increase with increase in the temperature and volume percentage of nanoparticles in the base fluid. The highest effective thermal conductivity at 60 °C was discovered when 0.2% volume percentage of nanoparticles have been added. The thermal conductivity of nanofluids increases with rising temperature (30 °C–60 °C) and nanoparticle volume fraction (0.5%–2%), as shown for CuO (13.1%–15.1%), MgO (18.2%–20.9%), SiO2 (5.2%–6.6%), and CeO2 (10%–12.9%) nanofluids. Numerous correlations have been adopted to compare with experimental effective thermal conductivity, such as Maxwell, Chandrasekar, and Corcine correlations. The Chandrasekar correlation consistently showed better agreement than the Maxwell and Corcine correlations when comparing the measured effective thermal conductivity to the effective thermal conductivity predicted by correlations at various temperatures and volume percentages. This present study is important as it offers insights into the optimization of nanofluids for improved thermal conductivity, which is advantageous for energy systems, cooling technologies, and industrial operations.