Convective heat transfer enhancement with nanoaerosols

Abstract

Hotwire experiments were conducted to study the effects of suspended 112nm diameter aluminum oxide (Al2O3) nanoparticles in air on the rate of convective heat transfer. The particle mass loading was varied between 0.01%<SL<0.34%, over a Reynolds number range of 600<Rew<900. The global Nusselt number was monitored to assess the magnitude of heat transfer enhancement. The results indicate up to a 36% increase in Nusselt number for a particle mass loading of 0.35% at a Reynolds number of 600. In contrast, results reported in the literature indicate a 50% increase in Nusselt number when 50μm diameter particles with a mass loading of 100% are dispersed in air with a Reynolds number of 10,000. Existing models for the prediction of Nusselt number increase for particle-gas suspensions have been modified for use with nanoaerosols over a range of Knudsen numbers. The limitations of and potential improvements to the modified empirical model are discussed.