Pub Date : 2025-12-16DOI: 10.1016/j.ijthermalsci.2025.110591
Xu Yan , Xiaowen Chen , Heng Zhang , Xiaohu Wu , Ning Chen
Water condensation on transparent surfaces causes light scattering, compromising transmittance and optical performance. Applying a photothermal conversion coating generating localized heating effectively reduces fogging. This study developed a solar-spectrum-selective photothermal anti-fog coating by embedding Cs0.33WO3 nanoparticles into a PVA–PA hydrogel. The coating shows high visible-light transmittance (69.5%) and strong near-infrared absorption (73.4%), with a smooth, uniform surface confirmed by SEM and surface roughness analyses. XRD and FTIR indicate the nanoparticles are physically incorporated without chemical reaction, preserving structural integrity. Under one-sun illumination, the coated glass temperature increased by 18.8 °C, 11.5 °C higher than bare glass, effectively suppressing fog formation. TGA, DTG, and water contact angle measurements confirm good thermal stability, mechanical integrity and maintained long-term hydrophilicity. This study contributes to the development of energy-saving building glass coatings by applying cesium tungstate nanoparticles to photothermal anti-fogging coatings.
{"title":"Highly transparent solar photothermal anti-fog coating based on cesium tungstate nanoparticles","authors":"Xu Yan , Xiaowen Chen , Heng Zhang , Xiaohu Wu , Ning Chen","doi":"10.1016/j.ijthermalsci.2025.110591","DOIUrl":"10.1016/j.ijthermalsci.2025.110591","url":null,"abstract":"<div><div>Water condensation on transparent surfaces causes light scattering, compromising transmittance and optical performance. Applying a photothermal conversion coating generating localized heating effectively reduces fogging. This study developed a solar-spectrum-selective photothermal anti-fog coating by embedding Cs<sub>0</sub>.<sub>33</sub>WO<sub>3</sub> nanoparticles into a PVA–PA hydrogel. The coating shows high visible-light transmittance (69.5%) and strong near-infrared absorption (73.4%), with a smooth, uniform surface confirmed by SEM and surface roughness analyses. XRD and FTIR indicate the nanoparticles are physically incorporated without chemical reaction, preserving structural integrity. Under one-sun illumination, the coated glass temperature increased by 18.8 °C, 11.5 °C higher than bare glass, effectively suppressing fog formation. TGA, DTG, and water contact angle measurements confirm good thermal stability, mechanical integrity and maintained long-term hydrophilicity. This study contributes to the development of energy-saving building glass coatings by applying cesium tungstate nanoparticles to photothermal anti-fogging coatings.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"222 ","pages":"Article 110591"},"PeriodicalIF":5.0,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787070","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}
Pub Date : 2025-12-15DOI: 10.1016/j.ijthermalsci.2025.110592
A. Akouibaa , R. Masrour , I. Koumiya , K. Abich , G. El Khttari , M. Benhamou , S. Mordane , M. Ouarch
The photothermal effects of plasmonic nanostructures, driven by surface plasmon resonance (SPR) and the resulting heat generation, are of growing interest for applications in cancer photothermal therapy (PTT). This study presents a numerical analysis of the thermal behavior of gold nanoparticles (AuNPs) excited by a continuous wave (cw) laser and embedded in various healthy and cancerous tissues, including Adrenal Gland, Blood, Breast (two cancer types), Cervical, and Skin. Using the finite element method (FEM), we evaluated light absorption and resulting heat generation in these tissues. Solving the heat diffusion equation enabled us to track the temporal and spatial temperature evolution in the AuNPs and surrounding tissues. Results reveal two thermal regimes: a transient phase defined by a time constant (τ) and a steady-state phase marked by a saturation temperature . Larger AuNPs reach higher temperatures due to their increased absorption cross-section. This study provides valuable insights into the key parameters influencing the efficiency of AuNPs in PTT, thereby contributing to the optimization of treatment protocols to maximize therapeutic impact while ensuring clinical safety. Moreover, the methodology developed in this work can be extended to other types of AuNPs, particularly anisotropic nanostructures such as nanorods, nanocages, and core–shell structures, thus paving the way for a broader exploration of photothermal approaches in nanomedicine.
{"title":"Thermoplasmonic heating kinetics of healthy and cancerous biological tissues using gold nanoparticles under continuous laser wave illumination","authors":"A. Akouibaa , R. Masrour , I. Koumiya , K. Abich , G. El Khttari , M. Benhamou , S. Mordane , M. Ouarch","doi":"10.1016/j.ijthermalsci.2025.110592","DOIUrl":"10.1016/j.ijthermalsci.2025.110592","url":null,"abstract":"<div><div>The photothermal effects of plasmonic nanostructures, driven by surface plasmon resonance (SPR) and the resulting heat generation, are of growing interest for applications in cancer photothermal therapy (PTT). This study presents a numerical analysis of the thermal behavior of gold nanoparticles (AuNPs) excited by a continuous wave (cw) laser and embedded in various healthy and cancerous tissues, including Adrenal Gland, Blood, Breast (two cancer types), Cervical, and Skin. Using the finite element method (FEM), we evaluated light absorption and resulting heat generation in these tissues. Solving the heat diffusion equation enabled us to track the temporal and spatial temperature evolution in the AuNPs and surrounding tissues. Results reveal two thermal regimes: a transient phase defined by a time constant (τ) and a steady-state phase marked by a saturation temperature <span><math><mrow><mi>δ</mi><msub><mi>T</mi><mi>max</mi></msub></mrow></math></span>. Larger AuNPs reach higher temperatures due to their increased absorption cross-section. This study provides valuable insights into the key parameters influencing the efficiency of AuNPs in PTT, thereby contributing to the optimization of treatment protocols to maximize therapeutic impact while ensuring clinical safety. Moreover, the methodology developed in this work can be extended to other types of AuNPs, particularly anisotropic nanostructures such as nanorods, nanocages, and core–shell structures, thus paving the way for a broader exploration of photothermal approaches in nanomedicine.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"222 ","pages":"Article 110592"},"PeriodicalIF":5.0,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787068","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}
Pub Date : 2025-12-15DOI: 10.1016/j.ijthermalsci.2025.110596
Jiahao Li , Ting Li , Yan Li , Jianping Sun , Lingling Chen , Jing Hu , Zhibin Liu , Hongpeng Guan
Correction of self-heating effects is essential for reducing uncertainties in negative temperature coefficient thermistor thermometers thermometry. In this study, the thermistor thermometers were calibrated at the triple point of water (TPW, 0.01 °C), the gallium melting point (GaMP, 29.7646 °C), and across the range from −0.5 to 30 °C using a thermostatic bath. Two correction methods—two-current and three-current—were compared. At the fixed points, the differences between the two methods were approximately 0.03 mK, and the self-heating effect observed at GaMP was approximately 30 % lower than that at TPW. To evaluate the reliability of each method, extrapolated R0 values were substituted into the calibration curves derived from both the two-current and three-current methods. The results showed that the three-current method deviated by ∼0.1 mK at TPW and ∼0.07 mK at GaMP, while the two-current method deviated by ∼0.18 mK and ∼0.12 mK, respectively. The three-current method yielded lower correction uncertainty and is preferred in water bath calibration. SPRT measurements at TPW showed a negligible difference (0.01 mK) between the two methods. The proposed calibration and evaluation procedure provides a practical framework for improving the accuracy of self-heating correction in both fixed-point and working environments.
{"title":"A comparative study of self-heating correction methods for high-precision thermistor thermometer calibration","authors":"Jiahao Li , Ting Li , Yan Li , Jianping Sun , Lingling Chen , Jing Hu , Zhibin Liu , Hongpeng Guan","doi":"10.1016/j.ijthermalsci.2025.110596","DOIUrl":"10.1016/j.ijthermalsci.2025.110596","url":null,"abstract":"<div><div>Correction of self-heating effects is essential for reducing uncertainties in negative temperature coefficient thermistor thermometers thermometry. In this study, the thermistor thermometers were calibrated at the triple point of water (TPW, 0.01 °C), the gallium melting point (GaMP, 29.7646 °C), and across the range from −0.5 to 30 °C using a thermostatic bath. Two correction methods—two-current and three-current—were compared. At the fixed points, the differences between the two methods were approximately 0.03 mK, and the self-heating effect observed at GaMP was approximately 30 % lower than that at TPW. To evaluate the reliability of each method, extrapolated <em>R</em><sub>0</sub> values were substituted into the calibration curves derived from both the two-current and three-current methods. The results showed that the three-current method deviated by ∼0.1 mK at TPW and ∼0.07 mK at GaMP, while the two-current method deviated by ∼0.18 mK and ∼0.12 mK, respectively. The three-current method yielded lower correction uncertainty and is preferred in water bath calibration. SPRT measurements at TPW showed a negligible difference (0.01 mK) between the two methods. The proposed calibration and evaluation procedure provides a practical framework for improving the accuracy of self-heating correction in both fixed-point and working environments.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"222 ","pages":"Article 110596"},"PeriodicalIF":5.0,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787020","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}
Pub Date : 2025-12-15DOI: 10.1016/j.ijthermalsci.2025.110577
Yiwen Geng, Zhenyu Liu, Huiying Wu
Phase-change transpiration cooling is an efficient thermal control solution for aerospace vehicles under hypersonic conditions. To predict its performance, a simplified equivalent numerical model is proposed for the liquid-gas phase change process in porous media, which innovatively introduces the Lee model and couples the two-phase mixture model, Darcy's equation, and local thermal non-equilibrium model. Additionally, by proposing a coupling method that simplifies the influence of the mainstream region on the phase-change transpiration cooling process within the porous region to pressure and heat flux boundary conditions applied at the interface, this approach avoids the requirement for multiple iterations while preserving computational accuracy, thus effectively reducing the complexity of the coupled solution. Using the improved numerical strategy, transient simulations of wedge-shaped porous cones under hypersonic conditions (Mach 6.5, altitude 30 km) have shown that: increasing the leading-edge radius or decreasing the half-apex angle reduces stagnation heat load but affects aerodynamic performance and structural reliability; regional graded porosity (especially circumferential gradient along the leading edge) lowers stagnation temperature by 41 K; regional control of coolant supply mitigates heat transfer deterioration, reducing the maximum temperature by over 350 K.
{"title":"Numerical investigation of phase-change transpiration cooling of wedge-shaped porous cone under hypersonic condition","authors":"Yiwen Geng, Zhenyu Liu, Huiying Wu","doi":"10.1016/j.ijthermalsci.2025.110577","DOIUrl":"10.1016/j.ijthermalsci.2025.110577","url":null,"abstract":"<div><div>Phase-change transpiration cooling is an efficient thermal control solution for aerospace vehicles under hypersonic conditions. To predict its performance, a simplified equivalent numerical model is proposed for the liquid-gas phase change process in porous media, which innovatively introduces the Lee model and couples the two-phase mixture model, Darcy's equation, and local thermal non-equilibrium model. Additionally, by proposing a coupling method that simplifies the influence of the mainstream region on the phase-change transpiration cooling process within the porous region to pressure and heat flux boundary conditions applied at the interface, this approach avoids the requirement for multiple iterations while preserving computational accuracy, thus effectively reducing the complexity of the coupled solution. Using the improved numerical strategy, transient simulations of wedge-shaped porous cones under hypersonic conditions (Mach 6.5, altitude 30 km) have shown that: increasing the leading-edge radius or decreasing the half-apex angle reduces stagnation heat load but affects aerodynamic performance and structural reliability; regional graded porosity (especially circumferential gradient along the leading edge) lowers stagnation temperature by 41 K; regional control of coolant supply mitigates heat transfer deterioration, reducing the maximum temperature by over 350 K.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"222 ","pages":"Article 110577"},"PeriodicalIF":5.0,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787021","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}
Pub Date : 2025-12-15DOI: 10.1016/j.ijthermalsci.2025.110597
Yu Sun, Wanying Liu, Yangyu Guo, Hong-Liang Yi
It remains a challenging task to model heat dissipation from nanoscale heat source due to its multiscale nature. In this work, we tackle this problem by a macroscopic phonon hydrodynamic model via a finite volume scheme with non-uniform grids. A temperature equation is obtained as the classical Fourier heat diffusion equation with the usual source term and an additional one proportional to the Laplacian of the heat source. Thus the present model provides a good prediction of temperature and heat flux fields in heat dissipation from various nanoscale heat sources, as long as their characteristic sizes are larger than few times the average phonon mean free path. For a non-monotonic Gaussian heat source, we show hotspots around its center and anomalous heat conduction from cold to hot regions. In the limit of large system size, we also derive formulas for both temperature and heat flux that enable fast evaluation of non-Fourier solution from the Fourier solution. Therefore, this study provides an efficient approach for non-Fourier heat conduction with nanoscale heat sources, and also a way to manipulate the hotspot by tuning the heat source distribution.
{"title":"Heat dissipation from nanoscale heat sources by phonon hydrodynamic model","authors":"Yu Sun, Wanying Liu, Yangyu Guo, Hong-Liang Yi","doi":"10.1016/j.ijthermalsci.2025.110597","DOIUrl":"10.1016/j.ijthermalsci.2025.110597","url":null,"abstract":"<div><div>It remains a challenging task to model heat dissipation from nanoscale heat source due to its multiscale nature. In this work, we tackle this problem by a macroscopic phonon hydrodynamic model via a finite volume scheme with non-uniform grids. A temperature equation is obtained as the classical Fourier heat diffusion equation with the usual source term and an additional one proportional to the Laplacian of the heat source. Thus the present model provides a good prediction of temperature and heat flux fields in heat dissipation from various nanoscale heat sources, as long as their characteristic sizes are larger than few times the average phonon mean free path. For a non-monotonic Gaussian heat source, we show hotspots around its center and anomalous heat conduction from cold to hot regions. In the limit of large system size, we also derive formulas for both temperature and heat flux that enable fast evaluation of non-Fourier solution from the Fourier solution. Therefore, this study provides an efficient approach for non-Fourier heat conduction with nanoscale heat sources, and also a way to manipulate the hotspot by tuning the heat source distribution.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"222 ","pages":"Article 110597"},"PeriodicalIF":5.0,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787067","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}
A two-phase flow thermo-hydrodynamic model (THD) is proposed and applied to LOX face seals with spiral groove. A nonlinear thermal-fluid coupling model is solved by the finite element method (FEM) across the fluid-three-dimensional solid domain interface. The phase change rate source term is resolved based on bubble dynamics theory and the saturation properties of LOX are fitted through NIST data. Several cases involving two-phase flow are analyzed and show good agreement with theoretical and experimental results. Furthermore, this study investigates the influence of phase change on spiral groove face seals. The results indicate that the temperature drop within the phase change region accounts for 20 %–30 % of the total temperature increase. Due to the variation of the physical properties in two-phase flow, the average flow velocity has an abrupt increase within the gas-liquid interface. And by phase change in dam region and flow accumulation within the spiral groove region, the average viscous dissipation is comparatively lower than other regions.
{"title":"Two-phase flow THD model validation and application in LOX face seals with spiral groove","authors":"Zhengxuan Hou, Xiangkai Meng, Mengjiao Wang, Wenjing Zhao, Xudong Peng","doi":"10.1016/j.ijthermalsci.2025.110572","DOIUrl":"10.1016/j.ijthermalsci.2025.110572","url":null,"abstract":"<div><div>A two-phase flow thermo-hydrodynamic model (THD) is proposed and applied to LOX face seals with spiral groove. A nonlinear thermal-fluid coupling model is solved by the finite element method (FEM) across the fluid-three-dimensional solid domain interface. The phase change rate source term is resolved based on bubble dynamics theory and the saturation properties of LOX are fitted through NIST data. Several cases involving two-phase flow are analyzed and show good agreement with theoretical and experimental results. Furthermore, this study investigates the influence of phase change on spiral groove face seals. The results indicate that the temperature drop within the phase change region accounts for 20 %–30 % of the total temperature increase. Due to the variation of the physical properties in two-phase flow, the average flow velocity has an abrupt increase within the gas-liquid interface. And by phase change in dam region and flow accumulation within the spiral groove region, the average viscous dissipation is comparatively lower than other regions.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"222 ","pages":"Article 110572"},"PeriodicalIF":5.0,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787066","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}
Pub Date : 2025-12-13DOI: 10.1016/j.ijthermalsci.2025.110576
Ying Yin , Hao An , Liang Gong , Yan Li , Zong-Bo Zhang
The increasing heat load in integrated electronic devices poses a great challenge for convection cooling in microchannels. In this paper, a novel interrupted coaxial pin-fin (ICP) structure is developed to enhance heat transfer and flow boiling stability in microchannels. A dynamic correction method for the mass transfer intensity factor is proposed to account for the deviation between the unit temperature and the boiling activation temperature. Based on the proposed model, the influences of structural parameters (e.g., pin-fin spacing, pin-fin gap width) and flow conditions on the heat transfer performance in the ICP microchannels are investigated. The results show that increasing the spacing improves the cooling effect, especially for the microchannel filled with staggered pin-fins outperforming inline arrangements, for which reduces bottom wall temperatures by 7.27 K and 7.22 K at 300 μm spacing. The staggered pin-fins structure enhances temperature uniformity and flow boiling stability, while increasing spacing raises pressure drop. Wider gap improves heat transfer, but also increases flow resistance. The heat transfer increases with Reynolds number (Re), but the flow resistance increases significantly beyond a Re of 300. The staggered ICP microchannel offers better heat transfer and flow stability, with the circular ICP structure effectively balancing heat transfer and resistance. These findings provide new insights for the development of a boiling flow in microchannel heat sinks.
{"title":"Enhancement of heat transfer and flow boiling stability in an interrupted coaxial pin-fin microchannel based on a dynamic correction method","authors":"Ying Yin , Hao An , Liang Gong , Yan Li , Zong-Bo Zhang","doi":"10.1016/j.ijthermalsci.2025.110576","DOIUrl":"10.1016/j.ijthermalsci.2025.110576","url":null,"abstract":"<div><div>The increasing heat load in integrated electronic devices poses a great challenge for convection cooling in microchannels. In this paper, a novel interrupted coaxial pin-fin (ICP) structure is developed to enhance heat transfer and flow boiling stability in microchannels. A dynamic correction method for the mass transfer intensity factor is proposed to account for the deviation between the unit temperature and the boiling activation temperature. Based on the proposed model, the influences of structural parameters (e.g., pin-fin spacing, pin-fin gap width) and flow conditions on the heat transfer performance in the ICP microchannels are investigated. The results show that increasing the spacing improves the cooling effect, especially for the microchannel filled with staggered pin-fins outperforming inline arrangements, for which reduces bottom wall temperatures by 7.27 K and 7.22 K at 300 μm spacing. The staggered pin-fins structure enhances temperature uniformity and flow boiling stability, while increasing spacing raises pressure drop. Wider gap improves heat transfer, but also increases flow resistance. The heat transfer increases with Reynolds number (<em>Re</em>), but the flow resistance increases significantly beyond a <em>Re</em> of 300. The staggered ICP microchannel offers better heat transfer and flow stability, with the circular ICP structure effectively balancing heat transfer and resistance. These findings provide new insights for the development of a boiling flow in microchannel heat sinks.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"222 ","pages":"Article 110576"},"PeriodicalIF":5.0,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733709","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}
Pub Date : 2025-12-13DOI: 10.1016/j.ijthermalsci.2025.110425
Long Zhou , Zhanchuang Cao , Ankur Jain , Xianfa Li
Heat conduction in multilayer composite media occurs commonly in several problems in engineering. This work derives an analytical solution for a two-dimensional multilayer heat conduction problem with a time-varying convective heat transfer boundary condition. Compared with traditional constant coefficient or one-dimensional models, the proposed model is relevant for more realistic and complex engineering problems. Heat generation and initial temperature are both assumed to be functions of space. Additionally, temporal variation in heat generation and thermal contact resistance between layers is also accounted for. This problem is solved using the shifting function method, in which, an integral transform is first applied to eliminate one spatial direction in the problem. The resulting problem is then solved by combining the shifting function method with the orthogonal expansion technique. The obtained results are compared with the existing literature and numerical simulations to verify the accuracy of the derived solution. Several types of problems with time-varying convective heat transfer coefficient functions that may be encountered in practical applications are also discussed. Results discussed here are releveant to the time-varying convective heat transfer coefficient characteristics produced by different cooling methods such as jet impingement cooling and periodic laminar cooling, and have potential relevance in engineering fields such as integrated circuit heat dissipation, functional gradient material design and metal quenching. This work helps improve the understanding and application of heat conduction problems in multilayer structures with time-varying convective heat transfer coefficients, and provides theoretical support for the design and optimization of related engineering problems.
{"title":"Analytical solution for two-dimensional multilayer transient thermal conduction with a time-varying convective boundary condition","authors":"Long Zhou , Zhanchuang Cao , Ankur Jain , Xianfa Li","doi":"10.1016/j.ijthermalsci.2025.110425","DOIUrl":"10.1016/j.ijthermalsci.2025.110425","url":null,"abstract":"<div><div>Heat conduction in multilayer composite media occurs commonly in several problems in engineering. This work derives an analytical solution for a two-dimensional multilayer heat conduction problem with a time-varying convective heat transfer boundary condition. Compared with traditional constant coefficient or one-dimensional models, the proposed model is relevant for more realistic and complex engineering problems. Heat generation and initial temperature are both assumed to be functions of space. Additionally, temporal variation in heat generation and thermal contact resistance between layers is also accounted for. This problem is solved using the shifting function method, in which, an integral transform is first applied to eliminate one spatial direction in the problem. The resulting problem is then solved by combining the shifting function method with the orthogonal expansion technique. The obtained results are compared with the existing literature and numerical simulations to verify the accuracy of the derived solution. Several types of problems with time-varying convective heat transfer coefficient functions that may be encountered in practical applications are also discussed. Results discussed here are releveant to the time-varying convective heat transfer coefficient characteristics produced by different cooling methods such as jet impingement cooling and periodic laminar cooling, and have potential relevance in engineering fields such as integrated circuit heat dissipation, functional gradient material design and metal quenching. This work helps improve the understanding and application of heat conduction problems in multilayer structures with time-varying convective heat transfer coefficients, and provides theoretical support for the design and optimization of related engineering problems.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"222 ","pages":"Article 110425"},"PeriodicalIF":5.0,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733759","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}
Pub Date : 2025-12-13DOI: 10.1016/j.ijthermalsci.2025.110578
Chuanliang Zhang, Rui Liu, Qian Wang
The airfoil channel printed circuit heat exchanger (PCHE) is promising for supercritical carbon dioxide Brayton cycle (sCO2-BC) owing to its excellent thermal–hydraulic performance. This study proposes the monolithic integration of airfoil fins and vortex-generating structures to further enhance the thermal-hydraulic performance of the PCHE channel through a unified, structurally robust design. Four configurations of integrated airfoil channels, incorporating barchan dune-shaped ramps (BDSRs), teardrop-shaped protrusions (TSPs), ellipse cylinders (ECs), and triangular cylinders (TCs), are investigated through numerical analysis. The results indicate that the introduction of vortex-generating structures significantly improves the heat transfer within the airfoil channel. Among these, the airfoil channel featuring TCs exhibits the highest thermal performance, with a 20.8 %–21.6 % increase in Nusselt number (Nu) relative to the standard airfoil channel. However, this enhancement in thermal performance is accompanied by higher pressure loss and frictional resistance, attributed to the generation of large-scale recirculation and secondary flow. In contrast, the airfoil channel featuring TSPs achieves the optimal thermal–hydraulic performance, with improvements of 1.4 %–11.5 % relative to the standard airfoil channel. This configuration, however, experiences a more pronounced performance degradation as the mass flow rate increases, indicating its suitability for low-flow conditions. Furthermore, the slots of BDSRs induce significant changes in the vortex structure, suppressing transverse vortices while enhancing longitudinal vortices, which improves flow and heat transfer characteristics of sCO2 within integrated airfoil channels. Among these slotted BDSRs, the configurations with S-BDSRs-II and S-BDSRs-III demonstrate superior thermal–hydraulic performance, achieving improvements of 7.8 %–12.1 % and 9.4 %–12.4 %, respectively, over the standard airfoil channel.
{"title":"Thermal-hydraulic performance of supercritical CO2 in PCHE channels with the integration of airfoil fins and vortex-generating structures","authors":"Chuanliang Zhang, Rui Liu, Qian Wang","doi":"10.1016/j.ijthermalsci.2025.110578","DOIUrl":"10.1016/j.ijthermalsci.2025.110578","url":null,"abstract":"<div><div>The airfoil channel printed circuit heat exchanger (PCHE) is promising for supercritical carbon dioxide Brayton cycle (sCO<sub>2</sub>-BC) owing to its excellent thermal–hydraulic performance. This study proposes the monolithic integration of airfoil fins and vortex-generating structures to further enhance the thermal-hydraulic performance of the PCHE channel through a unified, structurally robust design. Four configurations of integrated airfoil channels, incorporating barchan dune-shaped ramps (BDSRs), teardrop-shaped protrusions (TSPs), ellipse cylinders (ECs), and triangular cylinders (TCs), are investigated through numerical analysis. The results indicate that the introduction of vortex-generating structures significantly improves the heat transfer within the airfoil channel. Among these, the airfoil channel featuring TCs exhibits the highest thermal performance, with a 20.8 %–21.6 % increase in Nusselt number (<em>Nu</em>) relative to the standard airfoil channel. However, this enhancement in thermal performance is accompanied by higher pressure loss and frictional resistance, attributed to the generation of large-scale recirculation and secondary flow. In contrast, the airfoil channel featuring TSPs achieves the optimal thermal–hydraulic performance, with improvements of 1.4 %–11.5 % relative to the standard airfoil channel. This configuration, however, experiences a more pronounced performance degradation as the mass flow rate increases, indicating its suitability for low-flow conditions. Furthermore, the slots of BDSRs induce significant changes in the vortex structure, suppressing transverse vortices while enhancing longitudinal vortices, which improves flow and heat transfer characteristics of sCO<sub>2</sub> within integrated airfoil channels. Among these slotted BDSRs, the configurations with S-BDSRs-II and S-BDSRs-III demonstrate superior thermal–hydraulic performance, achieving improvements of 7.8 %–12.1 % and 9.4 %–12.4 %, respectively, over the standard airfoil channel.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"222 ","pages":"Article 110578"},"PeriodicalIF":5.0,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733708","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}
Pub Date : 2025-12-12DOI: 10.1016/j.ijthermalsci.2025.110593
Yue Cui , Zhiwei Qiu , Yewei Gui , Yanxia Du , Fanbo Sun , Dong Wei
Simultaneous online reconstruction of internal temperature fields and wall thickness in high-temperature structures is critical for ensuring structural integrity and thermal safety. Traditional inversion methods based on ultrasonic transit time face limitations such as low computational efficiency and slow convergence, especially when dealing with the strongly coupled inverse problem of temperature field and thickness. To overcome these bottlenecks, we propose a novel alternating iteration algorithm that synergistically couples the Limited-memory Broyden–Fletcher–Goldfarb–Shanno (L-BFGS) method for heat flux inversion with the Steepest Descent (SD) method for thickness retrieval. Both numerical and experimental validations demonstrate that the proposed L-BFGS-SD algorithm enhances computational efficiency by 30–80 % over conventional methods while maintaining high accuracy (temperature relative error <5 %, thickness deviation <0.1 mm). Notably, the algorithm's robustness and insensitivity to initial guesses are further validated under dynamic thermal loads. This work thus presents an efficient, and robust method for the real-time monitoring and thermal safety assessment of high-temperature equipment.
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