Basheed G A, Jain Komal, Pathak Saurabh, Pant R P
CSIR-National Physical Laboratory, Dr. K.S. Krishna Road, New Delhi 110012, India; Academy of Scientific and Innovative Research-NPL Campus, New Delhi 110012, India.
J Nanosci Nanotechnol. 2018 Apr 1;18(4):2746-2751. doi: 10.1166/jnn.2018.14532.
We investigate the effect of dilution on dipolar interaction with linear and non-linear rheological properties of kerosene based magnetic fluid. The steady-state behavior demonstrate a shear thinning behavior and corroborated with a power law, (η = c n + η∞) exponent, n ≤ 1. The shear-induced-breakup (separation) of nanoparticles and the yielding behavior has been explained by Bingham model. Moreover, the magnetoviscous effect showed an initial increase at low shear rate and decrease at higher shear rate. Further, specific viscosity (ηF)-versus-Mason number (Mn) shows a perfect scaling at lower Mn (≤10-4) confirming negligible thermal and colloidal forces. Whereas, at higher Mn (≥10-3) deviation from collapse indicates the dominance of Brownian forces acting on nanofluids. The magnetic field dependent elastic (G') and viscous (G″) modulus reveal a crossover from viscoelastic-to-viscous behavior of nanofluid at critical concentration. Finally, we compare viscoelastic results with De Gans diagonal scaling theory to correlate the functional dependence of storage and loss modules with different particle volume concentration.
我们研究了稀释对基于煤油的磁性流体的偶极相互作用以及线性和非线性流变特性的影响。稳态行为表现出剪切变稀行为，并与幂律（η = c n + η∞）指数n ≤ 1相符。纳米颗粒的剪切诱导破裂（分离）和屈服行为已由宾汉模型进行了解释。此外，磁黏效应在低剪切速率下呈现出初始增加，而在高剪切速率下则降低。进一步地，比黏度（ηF）与梅森数（Mn）在较低的Mn（≤10 - 4）时呈现出完美的标度关系，证实了热和胶体作用力可忽略不计。然而，在较高的Mn（≥10 - 3）时偏离塌缩表明作用于纳米流体的布朗力占主导地位。磁场依赖性弹性（G'）和黏性（G″）模量揭示了在临界浓度下纳米流体从黏弹性到黏性行为的转变。最后，我们将黏弹性结果与德根斯对角线标度理论进行比较，以关联储能模量和损耗模量与不同颗粒体积浓度的函数依赖性。
