Ahmad Azari

Mass diffusivity of CO2 in different nanofluids was estimated by a designed measurement set up. For conducting diffusion tests, water-based nanofluids, including silicon oxide (SiO2), aluminum oxide (Al2O3), and titanium oxide (TiO2) with the concentrations of 0.05, 0.1, and 0.2 wt% were prepared and characterized by dynamic light scattering analysis. The effect of operational parameters such as temperature, the weight percentage of nanoparticles, and the size of nanoparticles on CO2 diffusivity was investigated by pressure decay measurement in a diffusion cell. According to the results of experiments, the most diffusivity improvement was related to TiO2 nanofluid (25 nm,) at 0.1 wt% and 35?C. CO2 diffusivity reached 14.7×10-9 m2/s which is about 4 times higher than that of pure water. In this study, a new correlation was developed for the effective diffusivity of CO2 in water-based nanofluid according to the nanoparticles Reynolds number, nanofluids Schmidt number, and nanofluids concentration. This correlation predicted CO2 diffusivity with an average relative error percent of 9.58% and a correlation coefficient (R2) of 0.945.