Document Type : Research Article
Department of Chemical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran
Department of Chemical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran.
In the present study, the dynamic viscosity and density of multi-wall carbon nanotube (MWCNT) nanoparticles and transformer oil at 0.05 to 0.8 wt% and room temperature are investigated. The carbon nanotubes were functionalized by carboxyl groups (-COOH) and also sodium dodecyl sulfate (SDS) surfactant was used to stabilize the nanoparticles in the base fluid. The inner diameter and length of the nanoparticles are between 10-20 nm and 3-8 µm respectively and purity is 98%. A correlation for the dynamic viscosity and density relative to the weight fraction of nanoparticles at ambient temperature is proposed, which indicates that viscosity and density increase with increasing the weight fraction, and the highest enhancement of dynamic viscosity and density are 21% and 2%, respectively. Dynamic viscosity at various shear stress and speeds also are investigated and the results show that with increasing shear stress, the viscosity increases about an average of 40.9%. The results were compared with other existing models to evaluate the accuracy of the results and, a review of other research on the nanofluid viscosity and density is done and their results are mentioned.