Influence of the Size of Spherical Nanoparticles on the Effective Thermal Conductivity of Nanofluids

Koller TM, Berger Bioucas FE, Hahn K, Rausch MH, Fröba AP (2025)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2025

Journal

Journal of Physical Chemistry C American Chemical Society

Book Volume: 129

Pages Range: 14265-14281

Journal Issue: 31

DOI: 10.1021/acs.jpcc.5c03930

Abstract

Motivated by contradictory statements in the literature, the present study provides an experimental and theoretical investigation on the influence of the size of spherical nanoparticles on the effective thermal conductivity λeffof nanofluids. Using dispersions of silicon dioxide or titanium dioxide in water or glycerol with particle diameters dpfrom (10 to 400) nm, λeffwas determined experimentally at temperatures between (283 and 358) K up to particle volume fractions φpof 0.31. For unimodal nanofluids containing nanoparticles with one size, the experimental results for λeffnormalized to the thermal conductivity of the base fluid λbfwere found to increase with increasing dp, until they reach a plateau above about 100 nm. This behavior is represented well by a prediction model that combines two approaches proposed in the literature. Here, a semiempirical model allows for representing λeffby the geometric mean of λbfand an effective thermal conductivity of the particles. The latter considers the particle thermal conductivity λpand a size-dependent Kapitza resistance at the particle/liquid interface. This new prediction model describes 301 measurement results for λeff·λbf–1of 15 different nanofluids at varying dp, φp, and T obtained from the present work and previous studies with an average absolute relative deviation of 2.2%. The same model could also be successfully applied to represent the experimental data for λeff·λbf–1of bimodal nanofluids containing two nanoparticle fractions with different sizes.

Authors with CRIS profile

Thomas Manfred Koller Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Michael Rausch Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Andreas Paul Fröba Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP)

Additional Organisation(s)

Erlangen Graduate School in Advanced Optical Technologies (SAOT)

Related research project(s)

Effektive Wärmeleitfähigkeit von Dispersionen mit einer flüssigen kontinuierlichen Phase Aug. 1, 2021 - July 31, 2024

How to cite

APA:

Koller, T.M., Berger Bioucas, F.E., Hahn, K., Rausch, M.H., & Fröba, A.P. (2025). Influence of the Size of Spherical Nanoparticles on the Effective Thermal Conductivity of Nanofluids. Journal of Physical Chemistry C, 129(31), 14265-14281. https://doi.org/10.1021/acs.jpcc.5c03930

MLA:

Koller, Thomas Manfred, et al. "Influence of the Size of Spherical Nanoparticles on the Effective Thermal Conductivity of Nanofluids." Journal of Physical Chemistry C 129.31 (2025): 14265-14281.

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