Experimental study of pool boiling performance of Fe3O4 ferromagnetic nanofluid on a copper surface

Abstract

Nanofluids significantly enhance the critical heat flux of boiling heat transfer. This paper experimentally investigates the pool boiling performance and the influence mechanism of Fe3O4 nanofluids. Compared with deionized water, the 0.001 vol% nanofluid increases a maximum enhancement in critical heat flux by 47.90%. During nanofluid boiling, Fe3O4 nanoparticles are deposited on the surfaces. The nanoparticle deposition surfaces are physically characterized to explain the influence mechanism of Fe3O4 nanoparticles on boiling heat transfer. Nanoparticle deposition modifies the surface micro-morphology, which increases roughness and improves wettability. The changes are essential factors for the enhancement of the critical heat flux. This paper further analyses the boiling results of deionized water on the nanoparticle deposition surfaces. Compared with a polished surface, the critical heat flux and heat transfer coefficient of the nanoparticle deposition surface show maximum increases of 52.39% and 56.19%. Due to the similar enhancement of critical heat flux using the Fe3O4 nanofluid and the nanoparticle deposition surface, it is found that the increased critical heat flux of the nanofluids is attributed to the improvement of surface wettability and roughness by nanoparticle deposition. This study analyzes the mechanism of Fe3O4 nanofluid for enhancing pool boiling heat transfer from the perspective of modifying boiling surface characteristics by nanoparticle deposition, especially in wettability and roughness, which advances the understanding of enhanced boiling heat transfer by nanofluids.