Experimental Investigation of Turbulent Convective Heat Transfer and Pressure Loss of Alumina/Water and Zirconia/Water Nanoparticle Colloids (Nanofluids) in Horizontal Tubes

Abstract

The turbulent convective heat transfer behavior of alumina (Al2O3) and zirconia (ZrO2) nanoparticle dispersions in water is investigated experimentally in a flow loop with a horizontal tube test section at various flow rates (9000<Re<63,000), temperatures (21–76°C), heat fluxes (up to ∼190kW∕m2), and particle concentrations (0.9–3.6vol% and 0.2–0.9vol% for Al2O3 and ZrO2, respectively). The experimental data are compared to predictions made using the traditional single-phase convective heat transfer and viscous pressure loss correlations for fully developed turbulent flow, Dittus–Boelter, and Blasius/MacAdams, respectively. It is shown that if the measured temperature- and loading-dependent thermal conductivities and viscosities of the nanofluids are used in calculating the Reynolds, Prandtl, and Nusselt numbers, the existing correlations accurately reproduce the convective heat transfer and viscous pressure loss behavior in tubes. Therefore, no abnormal heat transfer enhancement was observed in this study.

The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes

“…The results show that, at constant velocity, the heat transfer coefficient of the 0.33 vol% MWCNT-water nanofluid is 3.3% lower, at 0.75 vol%, it is 6.6% lower and at 1.0 vol%, it is 12.6% lower than that of distilled water. This trend of lower heat transfer coefficients in nanofluids compared with water was also experienced by Pak and Cho [6], Williams et al [41] and Yu et al [40]. However, at very high velocities, the heat transfer coefficients of the 0.33 vol% MWCNT-water nanofluid equal that of the distilled water.…”

“…[40], Williams et al [41] and Liu and Liao [16]. The properties of the nanofluids, such as the thermal conductivity and viscosity were determined from Equation 2 and 3.…”

Entropy Generation during Turbulent Flow of Zirconia-water and Other Nanofluids in a Square Cross Section Tube with a Constant Heat Flux

“…For validation the present model predictions are compared with the experimental data of Williams et al [43] in Figure 2. Comparisons are done for three concentrations of 0.2%, 0.5% and 0.9% for ZrO2-water nanofluids.…”

CFD assessment of the effect of nanoparticles on the heat transfer properties of acetone/ZnBr2 solution

“…Some researchers [13][14][15] reported that heat transfer in nanofluids can be modelled using classical correlations (based on Maxwell) for single-phase fluids with adjustment for properties with the nano-particles. Others stated that the heat transfer behaviour obeys a two phase model with variation due to concentration of nano-particles varying in the flow.…”