Xudong Yuan , Chuanye Tang , Hongying Qu , Xiujuan Yang , Zhiyuan Li , Shicheng Ding , Qian Hu
{"title":"Dynamic polarization effect and lithium-ions distribution non-uniformity coupling heat generation characters inside lithium-ion cell with battery cell design","authors":"Xudong Yuan , Chuanye Tang , Hongying Qu , Xiujuan Yang , Zhiyuan Li , Shicheng Ding , Qian Hu","doi":"10.1016/j.ijthermalsci.2025.110366","DOIUrl":"10.1016/j.ijthermalsci.2025.110366","url":null,"abstract":"<div><div>Electrode structure sizes including negative electrode volume fraction <em>ε</em><sub>s,n</sub>, positive electrode volume fraction <em>ε</em><sub>s,p</sub>, negative electrode particle radius <em>r</em><sub>p,n</sub> and positive electrode particle radius <em>r</em><sub>p,p</sub> are key design parameters of lithium-ion cell. To assess the impacts of electrode structure sizes on heat generation, polarization effect expressed by over-potential and lithium-ions diffusion in lithium-ion cell, an electrochemical-thermal coupling model with battery cell design was presented for a numerical investigation at charge rate 1C and ambient temperature 25 °C. The results indicate that when volume fraction or particle radius of electrode increases, total heat generation power <em>q</em><sub>tot</sub> increases. Increasing <em>ε</em><sub>s,p</sub> increases over-potential <em>η</em> peak of negative electrode, while decreases <em>η</em> of positive electrode in the middle and late stage of charge. <em>η</em> of negative electrode at <em>r</em><sub>p,n</sub> = 7 μm increases by 150 % compared to that at <em>r</em><sub>p,n</sub> = 3 μm. <em>η</em> of positive electrode at <em>r</em><sub>p,p</sub> = 5.5 μm increases by 240 % compared to that at <em>r</em><sub>p,p</sub> = 1.5 μm. Increasing <em>ε</em><sub>s,n</sub> increases and decreases respectively the lithium-ion concentration gradients <em>grad</em><sub><em>c</em>e</sub> of negative electrolyte and positive electrolyte. While increasing <em>ε</em><sub>s,p</sub> increases <em>grad</em><sub><em>c</em>e</sub> in the whole cell. When <em>ε</em><sub>s,n</sub> or <em>ε</em><sub>s,p</sub> increases from 0.3 to 0.7, lithium-ion concentration difference between surface and center of electrode particle Δ<em>c</em><sub>s</sub> decreases by 35 % or 60 %. If <em>r</em><sub>p,n</sub> increases or <em>r</em><sub>p,p</sub> decreases, Δ<em>c</em><sub>s</sub> of negative and positive electrodes increases and decreases respectively. Lithium-ion cell considering battery thermal management system was numerically studied at charging rate of 3C and initial cell temperature of 35 °C. When working medium temperature decreases or heat transfer coefficient increases, lithium-ion diffusion coefficient and redox reaction rate decrease, thus <em>q</em><sub>tot</sub>, <em>η</em>, <em>grad</em><sub>ce</sub> and Δ<em>c</em><sub>s</sub> all increase.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110366"},"PeriodicalIF":5.0,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Song Yang , Yu Hou , Kequan Xia , Tom Reddyhoff , Min Yu
{"title":"Interfacial dynamics of NaCl solution droplets impact on cold surfaces: spreading and salt-induced phase transition","authors":"Song Yang , Yu Hou , Kequan Xia , Tom Reddyhoff , Min Yu","doi":"10.1016/j.ijthermalsci.2025.110375","DOIUrl":"10.1016/j.ijthermalsci.2025.110375","url":null,"abstract":"<div><div>Understanding the interfacial behavior of saline droplets impacting cold surfaces is critical for a wide range of thermal, environmental, and crystallization-related applications. This study experimentally investigates the spreading and phase separation dynamics of NaCl solution droplets on temperature-controlled hydrophilic silicon surfaces. Using a custom-built platform with high-speed imaging, we captured the full evolution of droplet morphology, including inertial spreading, salt-induced phase separation, and final solidification. The influences of impact height, surface temperature, and salt concentration were systematically investigated. A modified empirical correlation for the maximum spreading factor was developed based on hydrophilic surface conditions, while retaining the theoretical Weber number scaling while adjusting fitting parameters to reflect salinity-induced changes in viscosity and surface tension. Building on this, a thermal response time model was adapted to account for the influence of concentration-dependent thermal diffusivity and freezing point depression. By introducing a dimensionless temperature parameter, an empirical correlation was proposed to predict the visual phase separation time as a function of both inertial and thermal effects. This unified framework shows strong agreement with experimental data across a broad range of conditions. The findings provide new insights into multicomponent droplet impact behavior and offer predictive tools for engineering systems involving freeze desalination, anti-icing coatings, and phase-controlled thermal microfluidics.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110375"},"PeriodicalIF":5.0,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luis M. Montes-de-Oca , Salomón E. Borjas-García , Nikte M. Gomez-Ortiz , Carlos Villaseñor-Mora , Pablo Martínez-Torres
{"title":"Study of the thermal conductivity of solid–liquid suspensions formed by mesoporous cerium oxide particles","authors":"Luis M. Montes-de-Oca , Salomón E. Borjas-García , Nikte M. Gomez-Ortiz , Carlos Villaseñor-Mora , Pablo Martínez-Torres","doi":"10.1016/j.ijthermalsci.2025.110363","DOIUrl":"10.1016/j.ijthermalsci.2025.110363","url":null,"abstract":"<div><div>This investigation employs the thermal wave resonator cavity (TWRC) technique to obtain the thermal diffusivity and quantify the thermal conductivity in suspensions composed of ethylene glycol loaded with mesoporous cerium oxide particles stabilized by Pluronic F-127. An analytical framework is proposed by combining the Lewis-Nielsen effective thermal conductivity model for composite materials with the Sumirat–Ando–Shimamura model for nanoporous materials to quantitatively describe the effects of volume fraction and porosity on thermal transport properties. This combined approach establishes a three-dimensional functional relationship between the thermal conductivity, porosity, and volume fraction. The mathematical model provides information on non-ideal particle packing configurations at high concentrations, enabling the predictive determination of suspension thermal conductivity based on microstructural parameters.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110363"},"PeriodicalIF":5.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jin Zhang , Yong Li , Yingchun Zhang , Jiajie Zhang , Gongnan Xie , Bengt Sunden
{"title":"High-fidelity LES of pin fin-jet configuration effects on supercritical n-decane flow and heat transfer in regenerative cooling channels","authors":"Jin Zhang , Yong Li , Yingchun Zhang , Jiajie Zhang , Gongnan Xie , Bengt Sunden","doi":"10.1016/j.ijthermalsci.2025.110378","DOIUrl":"10.1016/j.ijthermalsci.2025.110378","url":null,"abstract":"<div><div>Active regenerative cooling technology is well-suited for extreme operating conditions characterized by high temperatures and intense thermal loads, serving as a highly effective approach for reducing combustion chamber wall temperatures. Large Eddy Simulation (LES) is employed to investigate the thermo-hydraulic characteristics of supercritical n-decane in a jet-regeneration cooling channel with the pin fin, focusing on the critical yet underexplored effects of pin fin-jet spatial configurations. The results indicate that the fluid flow within the jet-regeneration cooling channel gradually evolves towards a quasi-steady state, accompanied by the breakdown process of large-scale vortex structures into small-scale turbulence. The introduction of the pin fin significantly enhances the distribution stability of the thermophysical properties of supercritical n-decane, facilitating uniform temperature field transfer and thereby boosting the overall heat transfer efficiency of the channel. Compared to the pin fin placement schemes in front of and directly below the jet, positioning the pin fin behind the jet effectively leverages the high turbulence intensity in the jet wake region, achieving an optimal balance between heat transfer enhancement and flow resistance suppression. Compared to the flat channel, this configuration leads to an average increase of 3.29 % in the Nusselt number (<em>Nu</em>) throughout 0–1.8 s, with an instantaneous maximum enhancement of 32.6 %. The Thermal-Hydraulic Performance Factor (<em>HTPF</em>) is notably superior to the benchmark value of unity, underscoring its comprehensive performance advantages.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110378"},"PeriodicalIF":5.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Design improvement of alumina feeding system in aluminum electrolytic cells with baked anodes","authors":"Ilya Ivanovich Puzanov , Nina Valeryevna Klimkina , Aleksandr Innokentyevich Bezrukikh , Igor Lazarevich Konstantinov , Nataliya Viktorovna Belousova , Marina Vladimirovna Voroshilova , Evgeniy Vladimirovich Ivanov","doi":"10.1016/j.ijthermalsci.2025.110379","DOIUrl":"10.1016/j.ijthermalsci.2025.110379","url":null,"abstract":"<div><div>The article presents the results of investigation on design improvement of the automatic alumina feed system in aluminum electrolytic cells with baked anodes. To achieve this goal, an innovative punch was developed to destroy the crust on the aluminum melt, the design of which includes a thermosyphon. Cooling the tip due to the thermosyphon eliminates the adhesion of raw materials to it, which improves the supply of alumina to the electrolyte, eliminates the need for complex cooling systems, reduces the likelihood of mechanical problems and increases the reliability of the equipment. Evaluation of the efficiency of the innovative punch in the production conditions of a metallurgical enterprise showed that the thermosyphon effectively dissipates heat, preventing raw materials from adhering to it. It was also determined that for the punch to work effectively, the ambient temperature should not exceed 24 °C, and the temperature of the exhaust gases should not be higher than 175 °C.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110379"},"PeriodicalIF":5.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lan Bo, Qiang Wang, Haiyang Hu, Yiwei Chen, Jifeng Huang
{"title":"Optimization study of film cooling scheme for two-dimensional convergent-divergent exhaust system considering thermal protection and infrared stealth requirements","authors":"Lan Bo, Qiang Wang, Haiyang Hu, Yiwei Chen, Jifeng Huang","doi":"10.1016/j.ijthermalsci.2025.110370","DOIUrl":"10.1016/j.ijthermalsci.2025.110370","url":null,"abstract":"<div><div>To address both the thermal protection demands during afterburning operation and the infrared stealth requirements during cruise in the early design stage of film cooling strategies, this study introduces a two-stage optimization framework for exhaust system film cooling configuration. In the first stage, the optimization targets the reduction of average component temperatures, while ensuring that infrared radiation remains within acceptable limits across the 30°–75° detection angle range. This process determines the optimal coolant mass flow distribution among system components by adjusting their respective area ratios. In the second stage, based on the optimized area ratios, each component is subdivided according to local thermal loads. This stage aims to minimize the temperature standard deviation of the heatshield surfaces, subject to the constraint that the maximum surface temperature remains below material limits. Streamwise and spanwise spacings of cooling holes in each region are tailored to meet localized cooling demands. Post-optimization results indicate substantial thermal uniformity improvements, with standard deviation reductions of 20.78 %, 21.90 %, and 30.52 % in the afterburner, convergent, and divergent sections, respectively. The highest local wall temperatures were also lowered by 7.70 % and 7.93 % in the afterburner and divergent sections. Additionally, infrared radiation intensity observed in the <em>xoz</em> and <em>yoz</em> planes decreased by 35.19 % and 32.38 %, indicating enhanced stealth capability.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110370"},"PeriodicalIF":5.0,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pardis Pakzadi Abnavi, Reza Kamali, Mohammad Reza Paydari
{"title":"Liquid-liquid slug flow in ribbed micro-channel heat sinks: Hydrodynamic-thermal analysis","authors":"Pardis Pakzadi Abnavi, Reza Kamali, Mohammad Reza Paydari","doi":"10.1016/j.ijthermalsci.2025.110368","DOIUrl":"10.1016/j.ijthermalsci.2025.110368","url":null,"abstract":"<div><div>The hydrothermal efficiency of liquid-liquid slug flow in novel configurations for fillet-free and filleted ribbed micro-channels was numerically investigated. This study addressed the following novel configurations: semi-circular ribbed micro-channel (MCHS-CR), semi-elliptic ribbed micro-channel (MCHS-ER), semi-circular ribbed micro-channel with filleted corners (MCHS-CR-FC), and semi-elliptic ribbed micro-channel with filleted corners (MCHS-ER-FC). effects of rib shapes and filleted corners on the hydrodynamic-thermal behavior of slug flow in micro-channels were studied at different inlet velocities. Adding ribs significantly enhanced heat removal compared to a smooth micro-channel (MCHS-S) in the presence of droplet two-phase flow. Heat transfer enhancement, caused by secondary flow generation and improved fluid advection, increased with rising flow velocity. Based on the results, incorporating fillets at the rib corners led to a significant enhancement in heat transfer, with a slightly escalated pressure drop. To assess the simultaneous influences of increasing the Nusselt number and the pressure drop, a performance evaluation criterion (PEC) was used. In comparison to the MCHS-CR and MCHS-ER configurations, the MCHS-CR-FC and MCHS-ER-FC designs raised the Nusselt number by about 6.1–8.3 % and 3.5–7 %, and improved about PEC 6–6.9 % and 3–6.2 %, respectively. Furthermore, the MCHS-ER-FC configuration, due to its superior circulation strength within the droplets, droplet intervals, and rib zones, yielded the greatest reduction in wall temperature and the highest heat transfer performance among all configurations studied.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110368"},"PeriodicalIF":5.0,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Enhanced thermohydraulic performance in helical coil heat exchangers using synthesized Cu-doped TiO2 nanofluids: An experimental approach","authors":"Altynay Sharipova , Mojtaba Shafiee , Marzieh Lotfi , Neila Ye Bekturganova","doi":"10.1016/j.ijthermalsci.2025.110338","DOIUrl":"10.1016/j.ijthermalsci.2025.110338","url":null,"abstract":"<div><div>With increasing global energy demand, environmental concerns, and the depletion of traditional resources, enhancing the efficiency of energy-intensive systems such as heat exchangers has become imperative. This study addresses this challenge by synthesizing copper-doped TiO<sub>2</sub> nanoparticles via a sol–gel method, aiming to simultaneously improve heat transfer rates and reduce pumping power—thereby overcoming the common issue of increased flow resistance in nanofluid applications and enhancing thermohydraulic performance in helical coil heat exchangers. Three Cu-doped TiO<sub>2</sub> samples were prepared with doping levels of 1 %, 3 %, and 5 % Cu, and characterized using FTIR, XRD, DLS, ICP-OES, and TEM analyses, confirming successful Cu<sup>2+</sup> incorporation and improved dispersion stability. Nanofluids based on pristine TiO<sub>2</sub> and the Cu-doped TiO<sub>2</sub> (5 wt% in deionized water) were tested in a horizontally oriented helical copper coil (inner diameter: 9.5 mm) across a Reynolds number range of 5,000 to 17,000. Cu doping markedly improved convective heat transfer, with TiO<sub>2</sub>–Cu<sub>5</sub> achieving 144.8 % maximum enhancement and a Synergistic Heat Transfer Enhancement of 56.5 %. While friction rose at low flow rates, drag reduction up to 24.6 % occurred at higher Reynolds numbers. Exergy efficiency also increased, peaking at 58 % for TiO<sub>2</sub>–Cu<sub>5</sub>, which reached the highest thermal–hydraulic enhancement factor of 2.25. These results demonstrate, for the first time, that Cu-doped TiO<sub>2</sub> nanofluids can simultaneously enhance heat transfer and flow efficiency in heat exchangers. This study presents the first correlations for Nusselt number and friction factor of TiO<sub>2</sub> and Cu-doped TiO<sub>2</sub> nanofluids in a helical tube, covering laminar and turbulent regimes.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110338"},"PeriodicalIF":5.0,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rongwei Bu , Chuangang Fan , Zhenyu Gao , Zengguang Liang , Guanjie Rao , Wenlong Wang , Tong Xu
{"title":"Eruptive burning of concave PMMA: Effect of curvature and width","authors":"Rongwei Bu , Chuangang Fan , Zhenyu Gao , Zengguang Liang , Guanjie Rao , Wenlong Wang , Tong Xu","doi":"10.1016/j.ijthermalsci.2025.110367","DOIUrl":"10.1016/j.ijthermalsci.2025.110367","url":null,"abstract":"<div><div>Polymethyl methacrylate (PMMA) is extensively utilized in the design of various architectural structures, including concave configurations. However, its inherent flammability poses a significant potential fire hazard. Investigation of upward flame spread over concave surfaces has been restricted to flame spread parameters, while the associated burning behaviors have not yet been addressed. In this study, 36 groups of fire experiments were performed on 3 mm thick PMMA with varying curvature (denoted by <em>K</em>, 0.52–2.00 m<sup>-1</sup>) and width (<em>W</em>, 2.5–15.0 cm). The results reveal that the mass loss rate undergoes an eruptive growth when <em>K</em> ≥ 1.41 m<sup>-1</sup>. By introducing a dimensionless parameter <em>Γ</em>, this burning behavior is quantitatively described using a piecewise power-law correlation between <em>Γ</em> and the Grashof number <em>Gr</em><sub><em>x</em></sub>. The critical occurrence of eruptive burning behavior is identified at <em>Gr</em><sub><em>x</em></sub> ≈ 3 × 10<sup>7</sup>. For <em>Gr</em><sub><em>x</em></sub> < 3 × 10<sup>7</sup>, flame convection mode in the pyrolysis zone is governed by natural convection, whereas forced convection becomes gradually dominant when <em>Gr</em><sub><em>x</em></sub> ≥ 3 × 10<sup>7</sup>. Subsequently, based on this critical threshold, the flame spread model before the occurrence of eruptive phenomenon is developed. This model reflects a power-law relationship between flame spread rate and pyrolysis length, with an average power exponent of 1.24.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110367"},"PeriodicalIF":5.0,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rasheed N. Abed, Mohammed Faris Abbas, Abdul Rahman N. Abed
{"title":"Experimentally and numerically investigation of the effect of CuO:Cr2O3 nanoparticles in a carbon ash coating on flat plate collectors, enhancing the absorption of solar energy collection","authors":"Rasheed N. Abed, Mohammed Faris Abbas, Abdul Rahman N. Abed","doi":"10.1016/j.ijthermalsci.2025.110347","DOIUrl":"10.1016/j.ijthermalsci.2025.110347","url":null,"abstract":"<div><div>The present work, a new nanocomposite film of carbon ash (C) doped nanoparticles (CuO and Cr<sub>2</sub>O<sub>3</sub>) at various concentrations was synthesized by a spin coating method. Tested across 238–900 nm wavelengths. These films aim to make a nanocomposite film as a coating over the flat plate collector to absorb the solar energy. The optical properties and Urbach energy were computed, and the analysis of scanning electron microscope/energy dispersive spectroscopy of carbon ash was used to illustrate the elemental compositions. The energy gap decreased from 3.95/1.4 eV, while Urbach energy increased from 12.35/34.48 eV as the disorder increased in the band gap. The atomic force microscope illustrated that the roughness increased from 2.73/9.33 nm, while the root mean square increased from 3.48/11.4 nm. The high dielectric constant increased from 1.893/3.330, the carrier concentration per effective mass values decreased from 8.193 × 10<sup>61</sup>/0.0511 × 10<sup>61</sup> (kg. m<sup>3</sup>)<sup>−1</sup>. The effective single oscillator energy values increased from 5.22/11.89 eV, the dispersion energy increased from 8.63/18.97 eV, the oscillator strength increased from 3.473 × 10<sup>13</sup>/14.68 × 10<sup>13</sup>, and the oscillator wavelength, decreased from 237.61/104.23 nm. The static refractive index decreased from 1.712/1.511, and the frequency dielectric constant decreased from 2.961/2.280. Linear susceptibility decreased from 0.156/0.127 esu, and non-linear susceptibility increased from 0.1012 × 10<sup>−14</sup> to 4.421 × 10<sup>−14</sup> esu. The computational fluid dynamics tools in ANSYS FLUENT were used to design a flat plate collector with a thin film nanocoating to predict heat loss efficiency and fluid temperature, and to increase the absorption efficiency of solar radiation to 67 %. These films coat flat plate collectors, concentrating thermal systems, optoelectronic devices, and dissipating heat from electronic systems.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110347"},"PeriodicalIF":5.0,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}