Forced Convective Heat Transfer in AL2O3-air Nanoaerosol

Abstract

Hotwire experiments were performed to assess the effects of suspended 100 nm diameter aluminum oxide (Al2O3) nanoparticles in air on the rate of convective heat transfer. The particle mass loading (0.01% < SL < 0.1%) was varied over a range of Reynolds numbers (1420 < Re < 10,310), while monitoring the global Nusselt number. The results indicate up to a 45% increase in the Nusselt number over the baseline air case for a particle mass loading of 0.1% at a Reynolds number of 7,500. The enhancement to heat transfer is an order of magnitude larger compared to results from related heat transfer experiments reported in the literature that used micron-sized aerosols at similar particle mass loadings. Potential application of the dispersion of nanoparticles into the intake air of a high-speed propulsion system is discussed. Nomenclature

Numerical study of heat transfer enhancement in the entrance region for low-pressure gaseous laminar pipe flows using Al2O3–air nanofluid

“…The volume fraction of the nanosolid particles of graphene is set to 0.01%. The figure shows that there is a 27 maximum error of less than 3% between the obtained results from the current code and these obtained by Akhavan-Zanjani et al 29 Finally, a comparison between the average Nusselt number against Reynolds number obtained from the current code and the experimental results obtained by Trivedi and Johansen 30 is presented in Figure 6. The comparison is carried out for the forced convective heat transfer in Al 2 O 3 -air nanoaerosol for three different cases, namely, air flow, nanofluid with mass fraction of 0.02%, and nanofluid with mass fraction of 0.1%.…”

“…Finally, a comparison between the average Nusselt number against Reynolds number obtained from the current code and the experimental results obtained by Trivedi and Johansen 30 is presented in Figure 6. The comparison is carried out for the forced convective heat transfer in Al 2 O 3 –air nanoaerosol for three different cases, namely, air flow, nanofluid with mass fraction of 0.02%, and nanofluid with mass fraction of 0.1%.…”

“…Comparison between results obtained from the current code to results obtained by Trivedi and Johansen. 30 …”