Magnetorheological behaviour of propylene glycol-based hematite nanofluids

Abstract

The study of nanofluids represents an innovative research area with remarkable development. Properties of ferric magnetic nanofluids, also denoted as ferrofluids, under the influence of an external magnetic field have attracted increasing attention. A set-up for performing rheological and magnetorheological tests of propylene glycol-based hematite (α-Fe 2 0 3 ) nanofluids is presented. The nanoparticle concentration dependence of the magnetorheological properties of this nanofluid was analysed at 303.15 K, ranging from 0.2 to 6.18 vol%, while external magnetic fields up to 0.7 T were applied. The rheological and magnetorheological experiments were performed using a rotational Physica MCR 101 rheometer, (Anton Paar), which is equipped with a magnetorheological device (MRD 170/1T) to control the magnetic flux density. A detailed study about the thixotropic behaviour of the samples as well as viscosity curves of magnetization and demagnetization responses, an analysis of the fractal dimension of the aggregates and conclusions about the magnetic field effect on the size of formed aggregates as a function of concentration has been developed in this work. Rheological tests show that the nanofluid studied presents non-Newtonian shear thinning, thixotropic and viscoelastic behaviour. Finally, the magnetic saturation of the material has been studied.

Heat Transfer Performance of Functionalized Graphene Nanoplatelet Aqueous Nanofluids

“…This is the reason why the use of nanofluids is one alternative with high potential for improving the energy efficiency of heat transfer processes. One of the current trends consists of the study of the effects and potential benefits resulting from the application of magnetic fields in heat transfer processes with nanofluids [ 10 , 32 , 33 , 34 , 35 , 36 ].…”

Effect of functionalized multiwalled carbon nanotubes on the mechanical, swelling and viscoelastic properties of gum ghatti-cl-poly(NIPAm) hydrogels

“…44,45 This effect, which became more visible as the - o -MWCNT concentration increased, was attributed to the resistance of the material to permanent deformation. 46,47 According to Fig. 8(b), it can be seen that as the strain (%) increased from 0.1–100 (%) for all the hydrogels, the loss factor value increased and approached the value of unity.…”