Experimental Investigation on Spray Cooling Heat Transfer Properties of Ethylene Glycol−Water-Based Nanofluids

Spray cooling is a practical solution for high heat flux heat dissipation problems. The spray cooling experiment was conducted with 50 wt% ethylene glycol aqueous solution as the base liquid in this paper. The effects of the concentrations of copper nanoparticles, copper oxide nanoparticles, silica nanoparticles, and surfactant Tween-20 on the heat transfer characteristics during spray cooling were investigated. The results showed that adding nanoparticles within a certain concentration range could enhance the effectiveness of spray cooling's heat transmission. Under the same conditions, adding copper nanoparticles has the best effect, followed by copper oxide nanoparticles, and silica nanoparticles have a relatively poor effect. Among them, the heat transfer coefficient and heat flux of the nanofluid could be raised by 10.58% and 11.34% in comparison to the base liquid when the concentration of copper nanoparticles was 0.01 wt%. As the concentration of nanoparticles rises higher, spray cooling's ability to transfer heat is hampered. Adding the surfactant Tween-20 could effectively improve the copper−water−ethylene glycol nanofluid's capacity for heat transmission. When the concentration is 3 ppm, the heat transfer coefficient and heat flux of the nanofluid with Tween-20 were increased by 9.81% and 10.38% compared to the copper−water−ethylene glycol nanofluid.