Influence of nanoparticles on reducing and enhancing evaporation mass transfer and its efficiency

Considering the importance of evaporation in various practical applications, an experimental investigation on reducing and enhancing evaporation ability of different nanoparticles was performed. A deliberately designed experimental device was used to measure the evaporation rate of nanofluids at different air velocities. Aqueous nanofluids with clay, TiO2, ZrO2, Fe2O3 and Ni/Fe nanopartides at the various concentrations were studied. The experimental results showed that depending on the type of nanoparticle, nanofluid evaporation can be decreased or increased. The results revealed that TiO2, ZrO2, Fe2O3 and Ni/Fe nanoparticles are able to reduce their base fluid evaporation rate, but clay nanoparticle increases its base fluid evaporation. The results also, showed that the nanofluid evaporation reduction or enhancement efficiency is affected by both nanoparticle concentration and air velocity. From the results it was also concluded that the evaporation efficiency curves of those nanoparticles that slow down their base fluid evaporation, were bowed inward and the efficiency curve of clay nanoparticle was bowed outward. (C) 2013 Elsevier Ltd. All rights reserved.