Experimental study of a universal CHF enhancement mechanism in nanofluids using hydrodynamic instability

Abstract

Pool boiling tests were designed and performed to confirm the relation between the enhancement of critical heat flux (CHF) in nanofluids and the development of a hydrodynamic instability on the test heater surface from the deposition of nanoparticles during boiling. These pool boiling experiments were carried out under atmospheric pressure using a 0.49 mm diameter cylindrical Ni-Cr wire as a heating element with ZnO, SiO2, SiC, Al 2O3, graphene oxide and CuO nanoparticles at 0.01% volume concentration. The test fluids are distilled water and R-123. The CHF value for each nanofluid is obtained and compared with the measured Rayleigh-Taylor wavelength. Higher CHF results have shorter Rayleigh-Taylor wavelengths in all cases. We propose a modified theoretical model for hydrodynamic instability that incorporates these effects and fits experimental results.