Experimental study on flow boiling heat transfer augmentation of novel zinc oxide coated copper hybrid nanofluids

Abstract

Understanding the nanofluid flow boiling phenomena is essential for many engineering applications including atomic reactors, cooling of electronic devices, synthetic buildings and spacecraft. Hybrid nanofluids, which are commonly defined as mixtures of two or more nanoparticles, are yet unknown to have improved features. When the coupled nanoparticles are suitably coated with one another, one on top of the other, this would be a successful technique as the usage of such nanofluids is hardly reported. The current research aims to investigate the effects of various novel hybrid ZnO coated Cu ( Cu@ZnO) nanofluid concentrations on the critical heat flux ( CHF) and heat transfer coefficient ( HTC) for their potential real-life application. The Cu@ZnO nanoparticles with hybrid properties were selected because Cu increased the conductivity of heat whereas ZnO improved chemical durability. Efficient spark discharge in liquid nitrogen was employed in three stages to produce robust Cu@ZnO nanoparticles with hybrid properties. In order to create durable nanofluids, the nanoparticles with mixed properties were dispersed using an ultrasonication process at four different volumetric concentrations: 0.025%, 0.050%, 0.075% and 0.1%. At 45°C, the nanofluids’ thermal conduction was 31% higher than that of base fluid. The flow boiling (subcooled) tests are carried out in minichannel with novel nanofluids. When the flow boiling investigation was being conducted, a greater concentration improved the HTC and CHF. In comparison to water, 0.1% of nanofluid caused the maximum rises in CHF and HTC, which were found to be 168.09% and 186.9%, respectively. It is possible for the fluid to utilize latent heat, create bubbles, distinct and delay the commencement of CHF because the thick Cu@ZnO-coated surface possesses strong thermal conductivity.