Effects of shear rate and temperature on viscosity of alumina polyalphaolefins nanofluids
Effects of shear rate and temperature on viscosity of alumina polyalphaolefins nanofluids
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DOI：
10.1063/1.3309478
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发表时间：
2010-03
影响因子：
3.2
通讯作者：
Sheng‐Qi Zhou;R. Ni;D. Funfschilling
中科院分区：
文献类型：
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作者：
Sheng‐Qi Zhou;R. Ni;D. Funfschilling
实验研究了氧化铝纳米流体粘度随剪切速率和温度的变化规律。氧化铝纳米流体是氧化铝纳米球或纳米棒在聚α烯烃（PAO）润滑剂中的悬浮液。基础流体PAO具有牛顿行为。在第一近似下，体积分数为φ = 1%和3%的纳米球以及φ = 1%的纳米棒的纳米流体可以被认为是牛顿流体，因为它们的粘度显示出非常弱的剪切速率依赖性。然而，我们的测量清楚地表明，这些纳米流体表现出一定的非牛顿特性，由于添加纳米粒子。此外，这些纳米流体的相对粘度（纳米流体的粘度与PAO的粘度的比率）已被测量为与温度无关。当纳米棒体积分数为3%时，纳米流体具有明显的非牛顿剪切变稀粘度和较强的温度依赖性。通过回顾以前的研究，近似的粘度是牛顿和相对粘度是独立的温度似乎适用于大多数低体积分数phi和低长径比纳米颗粒的纳米流体。(C)2010年美国物理学会。[doi 10.1063/1.3309478]
In this paper, the shear rate and temperature dependencies of viscosity of alumina nanofluids have been investigated experimentally. The alumina nanofluids are suspensions of alumina nanospheres or nanorods in polyalphaolefins (PAO) lubricant. The base fluid PAO has a Newtonian behavior. To the first approximation, nanofluids of volume fractions phi = 1% and 3% nanospheres as well as nanofluid of phi = 1% nanorods can be considered as Newtonian fluids because their viscosity shows very weak shear rate dependence. However, our measurement clearly indicates that these nanofluids demonstrate certain non-Newtonian feature due to the addition of nanoparticles. Moreover, the relative viscosity (the ratio of viscosity of nanofluid to that of PAO) of these nanofluids has been measured to be independent of temperature. Nanofluid of a higher volume fraction phi = 3% nanorods has an apparent non-Newtonian shear thinning viscosity and a strong temperature dependence of its relative viscosity. By reviewing the previous studies, the approximation that the viscosity is Newtonian and the relative viscosity is independent of temperature seem to hold for most nanofluids of low volume fraction phi and low aspect ratio nanoparticles. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3309478]