Experimental and theoretical investigations on alumina-water nanofluid viscosity with statistical analysis

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2013

Author

Elçioğlu, Elif Begüm

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Nanofluids are nanoparticles’ colloidal suspensions. Due to their enhanced thermal conductivity, nanofluids are regarded as advantageous for high efficiency requiring heat transfer applications. On the other hand, the viscosity of nanofluids is greater than those of base fluids. Since the pumping power requirement, which is related to operation cost, is higher for high viscosity fluids, the viscosity of nanofluids should be carefully investigated. Enhancements in nanofluid thermophysical properties are related to the nanoparticle fraction within the base fluid. Therefore, concentrated nanofluids are more advantageous in terms of their high thermal conductivity. However, viscosity is also high for concentrated nanofluids. Therefore, balancing the advantages of the thermal conductivity enhancement and drawbacks of the viscosity enhancement of nanofluids is important. The aim of this thesis is to experimentally and theoretically investigate the nanofluid viscosity with detailed statistical analysis. Toward this aim, first a detailed benchmarking of the subject is performed. The unique parts of this thesis are: experimental investigation on Al2O3–H2O nanofluid viscosity for varying nanoparticle volumetric fractions (φ), nanoparticle diameters (dp), and temperatures (T); and statistical analysis on the experimental data. The experiments showed that, the viscosity of Al2O3–H2O nanofluids increased with φ and dp, and decreased exponentially with T. The statistical analysis showed that, the main effects of φ , dp and T, and the interaction effect of T and φ on nanofluid viscosity; and the main effects of φ and dp on relative viscosity are found to be significant. In addition, new nanofluid viscosity and relative viscosity correlations are presented.

Subject Keywords

Nanofluids., Viscosity., Taguchi Method.

URI

http://etd.lib.metu.edu.tr/upload/12616062/index.pdf
https://hdl.handle.net/11511/22644

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

E. B. Elçioğlu, “Experimental and theoretical investigations on alumina-water nanofluid viscosity with statistical analysis,” M.S. - Master of Science, Middle East Technical University, 2013.