Application of general multilevel factorial design approach in forced convection and subcooled flow boiling heat transfer to CuO/water nanofluids

In this research, heat transfer in forced convection and subcooled flow boiling to CuO/water nanofluids was experimentally and theoretically investigated. The effects of various parameters comprising subcooling temperature, nanoparticle concentration, heat flux, and fluid flow rate on the heat transfer performance of the system were studied. The general multilevel factorial design approach was applied in order to design the experiments and statistically analyze the results. Results showed that all the aforementioned factors were statistically significant. A reduced quadratic model was presented to predict the heat transfer coefficient. The suggested model was in good agreement with the experimental data. It was found the heat transfer coefficient increase as the heat flux and fluid flow rate increase while the trend was reversed for the effect of subcooling temperature. Raising the nanoparticle concentration initially deteriorated the heat transfer coefficient while a further increase in concentration enhanced the heat transfer coefficient. (C) 2020 Elsevier B.V. All rights reserved.