Methods for the determination of the optical properties of both conventional and hybrid nanofluids are presented. The optical properties considered included the extinction coefficient, absorptance, transmittance, and reflectivity. Experimental, theoretical, and numerical approaches for the evaluation of the optical properties are reviewed. The effects of nanoparticle concentration, size, and shape on the optical properties are discussed. The influence of the base fluid on the optical properties is examined. The dependence of the optical properties on the wavelength is investigated. Results of various analytical and numerical procedures and their validation with the experimental measurements are presented. It is concluded that the optical behavior of nanofluids can be optimized by simultaneous consideration of proper size, shape, concentration, nanoparticles material, base fluid, weather condition, and the wavelength range. Hybridization is found to be a promising choice for improving the optical properties of nanofluids. Hybrid nanofluids received an increasing attention recently and there is need for further research in the direction of hybrid nanofluids and their optical properties. As water is commonly used as the base fluid extensive literature is found for water base nanofluids. On the other hand, non-water-based nanofluids with enhanced optical properties are still potential future research areas.

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纳米流体光学特性的测定方法：综述

介绍了确定常规和混合纳米流体的光学特性的方法。考虑的光学特性包括消光系数、吸收率、透射率和反射率。评述了用于评估光学特性的实验、理论和数值方法。讨论了纳米粒子浓度、大小和形状对光学特性的影响。检查了基液对光学特性的影响。研究了光学特性对波长的依赖性。介绍了各种分析和数值程序的结果及其与实验测量的验证。结论是纳米流体的光学行为可以通过同时考虑适当的尺寸、形状、浓度、纳米颗粒材料、基液、天气条件和波长范围。发现杂化是改善纳米流体光学特性的有希望的选择。混合纳米流体最近受到越来越多的关注，需要进一步研究混合纳米流体及其光学特性。由于水通常用作基液，因此可以找到大量有关水基纳米流体的文献。另一方面，具有增强光学特性的非水基纳米流体仍然是未来潜在的研究领域。混合纳米流体最近受到越来越多的关注，需要进一步研究混合纳米流体及其光学特性。由于水通常用作基液，因此可以找到大量有关水基纳米流体的文献。另一方面，具有增强光学特性的非水基纳米流体仍然是未来潜在的研究领域。混合纳米流体最近受到越来越多的关注，需要进一步研究混合纳米流体及其光学特性。由于水通常用作基液，因此可以找到大量有关水基纳米流体的文献。另一方面，具有增强光学特性的非水基纳米流体仍然是未来潜在的研究领域。