Acevedo-Barrera Anays, Garcia-Valenzuela Augusto
Opt Express. 2019 Sep 30;27(20):28048-28061. doi: 10.1364/OE.27.028048.
Currently, there are available a few simple analytical approximations to the complex effective refractive index that may be used for nanofluids. Namely, the Maxwell Garnett mixing formula with scattering corrections, the Maxell Garnett Mie approximation, the Foldy-Lax approximation and the small particle limit of the quasi-crystalline approximation. These approximations are valid either for very small nanoparticles (below a few nanometers in radius) or for very dilute nanofluids (below about 1% in particles' volume fractions) and therefore, do not cover the whole domain of particle suspensions referred to as nanofluids. Here we propose a new simple analytical approximation based on local field corrections to the Foldy-Lax approximation. The new mixing formula coincides with the mentioned approximations when they are expected to be valid and provides physically sound predictions when the mentioned approximations are no longer valid, within the realm of nanofluids. We compare predictions of the analytical approximations considered in this work with experimental data published earlier for nanofluids of polystyrene in water.
目前，对于可用于纳米流体的复有效折射率，有一些简单的解析近似方法。具体来说，有带散射修正的麦克斯韦·加内特混合公式、麦克斯韦·加内特米近似、福迪 - 拉克斯近似以及准晶近似的小粒子极限。这些近似方法要么适用于非常小的纳米粒子（半径小于几纳米），要么适用于非常稀的纳米流体（粒子体积分数低于约1%），因此，并未涵盖被称为纳米流体的整个粒子悬浮液领域。在此，我们基于对福迪 - 拉克斯近似的局部场修正提出一种新的简单解析近似方法。当上述近似方法预期有效时，新的混合公式与它们一致，并且在纳米流体范围内，当上述近似方法不再有效时，能给出符合物理实际的预测。我们将本工作中考虑的解析近似方法的预测结果与先前发表的关于水中聚苯乙烯纳米流体的实验数据进行比较。
