Effect of nanoparticles on critical heat flux of water in pool boiling heat transfer

Abstract

The present study is to enhance the critical heat flux (CHF) in pool boiling from a flat square heater immersed in nanofluid (water mixed with extremely small amount of nanosized particles). The test results show that the enhancement of CHF was drastic when nanofluid is used as a cooling liquid instead of pure water. The experiment was performed to measure and compare pool boiling curves of pure water and nanofluid at the pressure of 2.89 psia ${\mathrm{(T}}_{\mathrm{sat}}\text{=60\hspace{0.05em}°}\mathrm{C})$ using $\text{1×1\hspace{0.17em}}{\mathrm{cm}}^2$ polished copper surfaces as a boiling surface. The tested nanofluid contains alumina $({\mathrm{Al}}_2{\mathrm{O}}_3)$ nanoparticles dispersed in distilled and deionized water. Tested concentrations of nanoparticles range from 0 g/l to 0.05 g/l. The measured pool boiling curves of nanofluids saturated at $\text{60\hspace{0.05em}°}\mathrm{C}$ have demonstrated that the CHF increases dramatically $\text{(∼200\%}$ increase) compared to pure water case; however, the nucleate boiling heat transfer coefficients appear to be about the same.