Investigating the effect of suspensions nanostructure on the thermophysical properties of nanofluids

Waka Tesfai, Pawan K. Singh, Salim J.S. Masharqa, Tewfik Souier, Matteo Chiesa, Youssef Shatilla

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The effect of fractal dimensions and Feret diameter of aggregated nanoparticle on predicting the thermophysical properties of nanofluids is demonstrated. The fractal dimensions and Feret diameter distributions of particle agglomerates are quantified from scanning electron and probe microscope imaging of yttria nanofluids. The results are compared with the fractal dimensions calculated by fitting the rheological properties of yttria nanofluids against the modified Krieger-Dougherty model. Nanofluids of less than 1 vol. % particle loading are found to have fractal dimensions of below 1.8, which is typical for diffusion controlled cluster formation. By contrast, an increase in the particle loading increases the fractal dimension to 2.0-2.2. The fractal dimensions obtained from both methods are employed to predict the thermal conductivity of the nanofluids using the modified Maxwell-Garnet (M-G) model. The prediction from rheology is found inadequate and might lead up to 8% error in thermal conductivity for an improper choice of aspect ratio. Nevertheless, the prediction of the modified M-G model from the imaging is found to agree well with the experimentally observed effective thermal conductivity of the nanofluids. In addition, this study opens a new window on the study of aggregate kinetics, which is critical in tuning the properties of multiphase systems.

Original languageBritish English
Article number114315
JournalJournal of Applied Physics
Issue number11
StatePublished - 1 Dec 2012


Dive into the research topics of 'Investigating the effect of suspensions nanostructure on the thermophysical properties of nanofluids'. Together they form a unique fingerprint.

Cite this