Experimental Study of Flow Critical Heat Flux in Alumina-Water, Zinc-Oxide-Water, and Diamond-Water Nanofluids

Abstract

It is shown that addition of alumina, zinc-oxide, and diamond particles can enhance the critical heat flux (CHF) limit of water in flow boiling. The particles used here were in the nanometer range (<100 nm) and at low concentration (≤0.1 vol %). The CHF tests were conducted at 0.1 MPa and at three different mass fluxes (1500 kg/m2 s, 2000 kg/m2 s, and 2500 kg/m2 s). The thermal conditions at CHF were subcooled. The maximum CHF enhancement was 53%, 53%, and 38% for alumina, zinc oxide, and diamond, respectively, always obtained at the highest mass flux. A postmortem analysis of the boiling surface reveals that its morphology is altered by deposition of the particles during boiling. Additionally, the wettability of the surface is substantially increased, which seems to correlate well with the observed CHF enhancement.

Forced Convective and Nucleate Flow Boiling Heat Transfer to Alumnia Nanofluids

“…Forced convective and Boiling heat transfer continue to be a subject of ongoing researches because of their potential to remove large amounts of heat at low temperature difference and a lack of validated models. Early studies of application of nanofluids in flow and pool boiling have mainly focused on critical heat flux and surface characteristics of a heating section as well as thermal conductivity enhancement and the parameters that govern this behavior [9][10][11][12][13][14][15]. Following literature briefly represents some recent works conducted on forced convective and flow boiling heat transfer of nanofluid.…”

Nanotechnology for Advanced Nuclear Thermal-Hydraulics and Safety: Boiling and Condensation

“…Kim et al [54] extended their flow boiling CHF studies to investigation of zinc-oxide and diamond-water nanofluids. The particles used were below 100 nm and at low concentration below 0.1 vol%.…”

CHF and near-wall boiling behaviors in pool boiling of water on a heating surface coated with nanoparticles

“…Further, pool boiling experiments with water based nanofluids by Bang and Chang [4] with Al2O3 for 4 mm×100 mm surfaces, Kim et al [5] with Al2O3 and TiO2 for horizontal wires, and Liu et al [6] with CuO for a 40×40mm surface with microgrooves reported CHF enhancements to be up to 1.5-3.0 times the CHF of water. In addition to these studies of pool boiling, Kim et al [7] carried out experiments of convective boiling with 55 mm inner diameter vertical tubes. They used Al2O3-water, ZnO-water, and diamond-water nanofluids and obtained 1.4 to 1.5 times enhancements of the CHF at mass flow rates of 2000-2500 kg/m 2 s. Ahn et al [8] measured the CHF for forced convective boiling of Al2O3-water nanofluids on a 10mm diameter upward facing disk, and reported 1.4 times the CHF of water.…”