Nucleate and Film Boiling Performance of Ethanol-Based Nanofluids on Horizontal Flat Plate: An Experimental Investigation

In this paper, the heat transfer characteristics of nanofluid nucleate and film boiling are studied experimentally. For this purpose, Al2O3 and SiO2 ethanol-based nanofluids prepared with three volumetric concentrations of 0.1 %, 0.3 %, and 0.5 %. The boiling experiments were conducted on a circular and polished copper surface with a diameter of 25 mm. The results showed that the addition of nanoparticles to the base fluid reduced the heat transfer coefficient of nucleate boiling. The critical heat flux of ethanol-based nanofluids was significantly higher than that of pure ethanol. The Al2O3 ethanol-based nanofluid with a volumetric concentration of 0.5 % had the best performance, with a critical heat flux of 42.36 % higher than that of pure ethanol. The presence of nanoparticles in the ethanol-based nanofluid improved the heat transfer coefficient of film boiling. The results showed that the stable film boiling for nanofluids starts at higher wall superheat temperature difference than pure ethanol. Among the investigated concentrations, volumetric concentration of 0.5 % had the best performance for both nanofluids, so that the minimum heat flux of Al2O3 and SiO2 ethanol-based nanofluids were increased by 45.96 % and 45.67 % compared to pure ethanol, respectively.