Analytical modeling and experimental investigation on optical properties of new class of nanofluids (Al sub(2)O sub(3)-CuO binary nanofluids) for direct absorption solar thermal energy

Nanofluids play a major role in many modern engineering processes. Binary nanofluids are a new class of nanofluids that are prepared by dispersing simultaneously two dissimilar nanoparticles in a base fluid. They offer a good potential for use in direct absorption solar systems. The present study in...

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Bibliographic Details
Published in:Optical materials 2016-02, Vol.52, p.116-125
Main Authors: Menbari, Amir, Alemrajabi, Ali Akbar
Format: Article
Language:English
Subjects:
ABSORPTION
ALUMINUM OXIDE
Coefficients
COPPER OXIDE
Dispersion
ETHYLENE
ETHYLENE GLYCOL
Extinction
FLUID FLOW
MATHEMATICAL ANALYSIS
MICROSTRUCTURES
Nanofluids
Nanoparticles
Nanostructure
OPTICAL PROPERTIES
PARTICLES
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Summary:Nanofluids play a major role in many modern engineering processes. Binary nanofluids are a new class of nanofluids that are prepared by dispersing simultaneously two dissimilar nanoparticles in a base fluid. They offer a good potential for use in direct absorption solar systems. The present study investigates both experimentally and analytically the optical properties of binary nanofluids for direct absorption in solar applications. For this purpose, two dissimilar nanoparticles, i.e. CuO and gamma -Al sub(2)O sub(3), are dispersed in water, ethylene glycol, and the ethylene glycol-water mixture to form binary nanofluids. In addition, a new method is developed for calculating the extinction coefficient of the binary nanofluids based on the classical electromagnetic theory. It will be shown that the extinction coefficients obtained from both analytical and experimental studies are in good agreement. Moreover, the extinction coefficient of the binary nanofluids is found to be approximately equal to the sum of the extinction coefficients of the constituent components, determined both analytically and experimentally. By increasing the nanoparticle volume fraction, improvements are observed in the extinction coefficient of the binary nanofluids prepared. Also, the analytical and experimental results of the study show that the extinction coefficient of the binary nanoparticles dispersed in water as the "base fluid" is greater than those of the binary nanoparticles dispersed in ethylene glycol or the mixture of ethylene glycol-water.
ISSN:0925-3467
DOI:10.1016/j.optmat.2015.12.023