Rheological characteristics of alumina (Al2O3) nanofluids (NFs) were found to exhibit an unexpected behavior. Two base-fluids viz, water and ethylene glycols (EG) with particles of average diameter of 11, 45 and 150 nm were examined. An anomalous reduction in viscosity compared to that of the base fluid was seen for EG based NFs. However, viscosity reduction was absent in water based NFs. The inter-related effects of particle size, concentration and mode of dispersion (mono or poly-dispersed) were investigated. Particle migration under shear is attributed to the reduction of viscosity. The increase in bulk viscosity with particle size reduction is attributed to the surface forces acting between the particles and the medium in a suspension and the increase of effective volume with size.
Anomalous Size Dependent Rheological Behavior of Alumina Based Nanofluids
Pawan SinghRelated information
1 Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India
, K. AnoopRelated information1 Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India
, H. PatelRelated information1 Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India
, T. SundararajanRelated information1 Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India
, T. PradeepRelated information2 Department of Chemistry and SAIF, Indian Institute of Technology Madras, Chennai-600036, India
, Sarit DasRelated information1 Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India
Published Online: June 29, 2010
Abstract