Vol.:(0123456789) 1 3 Journal of Thermal Analysis and Calorimetry https://doi.org/10.1007/s10973-019-09215-3 Application of nano‑quantitative structure–property relationship paradigm to develop predictive models for thermal conductivity of metal oxide‑based ethylene glycol nanofuids Kimia Jafari 1  · Mohammad Hossein Fatemi 1 Received: 9 July 2019 / Accepted: 17 December 2019 © Akadémiai Kiadó, Budapest, Hungary 2020 Abstract In this work, the relatively thermal conductivity of metal oxide-based ethylene glycol nanofuids is being predicted by using quantitative structure–property relationship methodology. The structural features of studied nanoparticles are represented by quasi-SMILES which is a coded linear structure. The gathered dataset includes ten types of nanoparticles (including Al 2 O 3 , MgO, TiO 2 , ZnO, Co 3 O 4 , CeO 2 , CuO, Fe 2 O 3 , Fe 3 O 4 , and SnO 2 ) suspended in the same base fuid, ethylene glycol. The calculated optimal descriptors acquired by applying the Monte Carlo method in the free software available on the Web (named CORAL) and four random splits into the training, invisible, calibration, and validation sets were appraised. The statistical characteristics confrmed the predictive power and reliability of the developed models; all splits had R 2 m more than 0.5 and ΔR 2 m less than 0.2, and also the validation set showed the correlation coefcient (R 2 ) in ranges 0.8611–0.6816 and cross-validated correlation coefcient (Q 2 ) in ranges 0.8518–0.6668. The presented models accurately predicted the thermal conductivity of all considered nanofuids, and the technique is expected to provide a novel way for future theoretical projects. Keywords Nanofuids · Thermal conductivity · Nano-QSPR · CORAL · Quasi-SMILES · Molecular features Introduction Heat transfer fuids have a signifcant efect in cooling and heating systems [1], heat exchange systems of power sta- tions [2], and vehicles air conditioning systems [3]. The most upshot on the overall efciency of the heat transfer mechanism is infuenced by the thermophysical proper- ties of heat carrier fuids. Therefore, scholars continuously made considerable eforts to enhance the performance and capability of heat transfer systems that, unfortunately, were constrained by the low thermal conductivity of ordinary fuids. With the progression in nanotechnology, nanofuids were introduced as alternative heat transfer fuids [4]. The term of nanofuid, coined by Choi [5], is used to describe a suspension containing nanoparticles with an average size less than 100 nm in any regular base fuid such as water, ethylene glycol, and methanol. Suspending nanoparticles led to remarkable improvements in the thermophysical prop- erties of classical liquids due to their nanosize and large specifc surface area. Improved thermophysical properties were exhibitive so that the use of nanofuids in various felds, such as renewable energy, chemical industry, and medicine, increased [6, 7]. Today, many studies have been done on the methods of preparation, stability, and thermal behavior of nanofuids [8–10]. Li et al. [11] gave us an outlook on the preparation and characterization of nanofuids, a subject that plays a key role. Ahmadi et al. [12] presented several experimental and theoretical studies conducted on the ther- mal conductivity of nanofuids in their recent review paper. They remarked some new approaches to obtain nanofuids with more adequate thermal properties such as utilizing binary fuids and preparing hybrid nanofuids. Żyła et al. [13] experimentally investigated thermophysical properties such as thermal conductivity and rheological behavior of ethylene glycol-based nanofuids containing titanium nitride nanoparticles with diferent volume fractions and various nanoparticle sizes at a constant temperature. In another Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10973-019-09215-3) contains supplementary material, which is available to authorized users. * Mohammad Hossein Fatemi mhfatemi@umz.ac.ir 1 Chemometrics Laboratory, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran