Dielectric relaxation effect on flow behavior of electrorheological fluids

Abstract

The dielectric relaxation effect on the flow behavior of electrorheological fluids under dynamic shear was studied. The flow curves of electrorheological fluids in the dynamic state were simulated with shear rates from 0.1 to 1000 s 21 under different relaxation times. When the magnitude of the relaxation time is smaller than 10 22 s, the break shear rate changes little at different relaxation times. But the break shear rate changes obviously when the magnitude of the relaxation time is larger than 10 22 s. To further understand the influence of the relaxation time, Sr/Ba-doped TiO 2 electrorheological fluids were prepared and their dielectric properties and flow curves under shear flow were tested. The relaxation time of the electrorheological fluid is influenced by the Sr/Ti mole ratio but not the Ba/Ti mole ratio, and the electrorheological effects of the fluids were highly influenced by varying the Sr/Ti mole ratios. The experimental results agreed well with the above computer simulation. Finally, a possible mechanism was proposed to explain the effect of dielectric relaxation on flow behavior of electrorheological fluids.

Influence of carrier liquid on nanoparticle-based giant electrorheological fluid

“…Even after years of intensive research, a fundamental correlation of the physicochemical properties involved in the GER effect has not been adequately developed (Chen and Wei, 2006;Shen et al, 2009;Stanway, 2004). There have been reports on the ER enhancing effect through the dispersing media and none has systematically investigated the role of the dispersing liquid (Choi and Jhon, 2009;Sheng and Wen, 2012;Wang et al, 2015). This is largely due to the conventional wisdom that the dispersing liquid plays only a passive role in providing a large mismatch between the dielectric constants of solid particles and oil (Cho et al, 2004).…”