Using MicroCT to Visualize Nanofluid Droplet Sorption Profiles in Unsaturated Porous Media

Liquid droplet sorption in unsaturated porous media is an important process for a wide range of applications. However, visualizing droplet sorption is difficult due to the opaque nature of porous media used in most of the applications. In this study, microCT is used to characterize the sorption profiles of single/multiple nanofuid droplets in PMMA powder beds. The microCT scan results reveal that the region of the powder bed saturated with nanofluid has a substantially higher gray scale value than that in the unsaturated region, thus enabling the visualization of the sorption profile. It also shows that nanoparticles enhance the visualization of the sorption profiles as they tend to accumulate and stay near the wetting front even after water evaporation.