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Tuning the dynamic thermal parameters of nanocarbon ionanofluids : a photopyroelectric study
Mohanachandran Nair Sindhu Swapna, Carmen Tripon, Alexandra Farcas, Dorin Dadarlat, Dorota Korte, Sankaranarayana Iyer Sankararaman, 2024, original scientific article

Abstract: The present work delineates the tailoring of the thermal effusivity and diffusivity of the novel class of heat transfer fluids—ionanofluids—by the incorporation of nanocarbons like diesel soot (DS), camphor soot (CS), carbon nanotubes (CN), and graphene (GR). When the thermal diffusivity delivers information on the thermal energy propagation, the thermal effusivity concerns the energy exchange at the interface, enabling energy-efficient thermal system design. The nanocarbons are subjected to morphological characterisation by field emission scanning electron microscopy. Fourier-transform infrared and Raman spectroscopic analyses confirm functional groups and vibrational bands. The microcrystalline size and graphiticity are also understood from the Raman spectrum. Ionanofluids prepared by dispersing nanocarbons into an ionic liquid base 1-Butyl-3-methylimidazolium methyl sulfate (BMMS) are analysed by nondestructive photopyroelectric calorimetry (PPE). The PPE analysis of ionanofluids demonstrates that nanocarbons influence thermal parameters in the base fluid, with soot ionanofluids exhibiting increased thermal effusivity and diffusivity due to their various carbon allotropic composition. This study underscores the importance of selecting the appropriate carbon allotrope for tailoring ionanofluids’ thermal properties, providing insights into manipulating these properties for enhanced performance across various industrial applications.
Keywords: photopyroelectric, ionanofluid, soot, graphene, thermal diffusivity
Published in RUNG: 06.05.2024; Views: 215; Downloads: 3
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Accuracy of measurements of thermophysical parameters by dual-beam thermal-lens spectrometry
Vladislav R. Khabibullin, Mladen Franko, Mikhail A. Proskurnin, 2023, original scientific article

Abstract: Thermal-lens spectrometry is a sensitive technique for determination of physicochemical properties and thermophysical parameters of various materials including heterogeneous systems and nanoparticles. In this paper, we consider the issues of the correctness (trueness) of measurements of the characteristic time of the thermal-lens effect and, thus, of the thermal diffusivity determined by dual-beam mode-mismatching thermal lensing. As sources of systematic errors, major factors— radiation sources, sample-cell and detector parameters, and general measurement parameters—are considered using several configurations of the thermal-lens setups, and their contributions are quantified or estimated. Furthermore, with aqueous ferroin and Sudan I in ethanol as inert colorants, the effects of the intermolecular distance of the absorbing substance on the correctness of finding the thermophysical parameters are considered. The recommendations for checking the operation of the thermal-lens setup to ensure the maximum accuracy are given. The results obtained help reducing the impact of each investigated factor on the value of systematic error and correctly measure the thermophysical parameters using thermal-lens spectrometry.
Keywords: thermal-lens spectrometry, accuracy, trueness, mode-mismatched schematic, measurements of thermal diffusivity
Published in RUNG: 20.01.2023; Views: 1280; Downloads: 13
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