Assessing Anatase TiO2 Nanofluids Performance: Experimental Heat Transfer Coefficients vs. Mouromtseff Number Ratios

This research aims to evaluate the efficacy of Mouromtseff’s numbers in assessing the thermal transfer performance of titanium oxide (TiO2) nanosized dispersions in convective heat transfer through a pipe. New experimental coefficients of convective heat transfer, thermophysical and rheological char...

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Bibliographic Details
Published in:Applied sciences 2024-09, Vol.14 (17), p.7647
Main Authors: Calviño, Uxía, Prado, Jose I., Vallejo, Javier P., Lugo, Luis
Format: Article
Language:English
Subjects:
anatase
Carbon
Conductivity
Efficiency
Figures-of-merit
Graphene
Heat conductivity
Heat exchangers
Heat transfer
Investigations
nanofluids
Nanoparticles
Particle size
Ratios
thermal analysis
thermophysical properties
titania
Titanium
Water
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Summary:This research aims to evaluate the efficacy of Mouromtseff’s numbers in assessing the thermal transfer performance of titanium oxide (TiO2) nanosized dispersions in convective heat transfer through a pipe. New experimental coefficients of convective heat transfer, thermophysical and rheological characterisation are carried out for TiO2-based nanodispersions in an aqueous propylene glycol 30 vol% mixture at various nanoadditive mass loadings (from 0.25 to 2.0 wt%). Different Mouromtseff’s number formulations, including the Dittus–Boelter and Simons expressions, were obtained from experimental data of thermophysical properties, enabling concise analyses on the prospective improvement of heat transfer in cooling and heating systems. The morphology, particle size, and crystallinity of the anatase TiO2 nanopowder were confirmed, and the stability of the nanofluids with various surfactants was evaluated, with PSS at a 1:4 mass ratio being optimal. Slight increments in thermal conductivity (up to 1.5%) and density (up to 1.3%) with nanoparticle loading were observed, while isobaric heat capacity presents a decreasing trend (less than 13%). Dynamic viscosity increases with higher nanoadditive concentrations, 8.8% for the 2.0 wt% A-TiO2/PG:W 30:70 + PSS 1:4 nanofluid. The employed Dittus–Boelter and Simons expressions correctly predict a worsening of the convective heat transfer, but the percentages diverge slightly from experimental data.
ISSN:2076-3417
2076-3417
DOI:10.3390/app14177647