Pub Date : 2026-01-28DOI: 10.1016/j.icheatmasstransfer.2026.110587
Attiq Ur Rehman , Hassaan Ahmad , Muhammad Faizan Ameer , Lubna Kanwal , Naseem Abbas , Dong Yang
Supercritical water (SCW) systems in advanced power generation and reactor designs operate under extreme conditions where strong property gradients can induce flow instabilities, affecting efficiency, safety, and reliability; however, experimental data for inclined tubes remain scarce due to testing challenges. Most studies on supercritical fluids assume uniform heating around the tube, an approach often impractical in real-world applications. This study addresses this limitation by analyzing the effect of non-uniform heating on flow instability in SCW within inclined tubes (0°-90°) under different operating conditions, such as pressure, inlet temperature (Tin), heat flux, and mass flow rate. Higher pressure and mass flow rate significantly enhance stability. Similarly, the higher the Tin enhances stability, with 573 K reducing fluctuations by ∼40% compared to 493 K. Higher heat flux generally stabilizes the flow at lower angles; it intensifies instability at higher inclination angles. Vertical orientation consistently shows the highest instability. These findings provide critical insights into the design and optimization of supercritical thermal systems, emphasizing the importance of integrated control of thermal, flow, and operating parameters to ensure stable and efficient operations.
{"title":"Numerical analysis of flow instability in inclined smooth parallel tubes at supercritical pressure","authors":"Attiq Ur Rehman , Hassaan Ahmad , Muhammad Faizan Ameer , Lubna Kanwal , Naseem Abbas , Dong Yang","doi":"10.1016/j.icheatmasstransfer.2026.110587","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110587","url":null,"abstract":"<div><div>Supercritical water (SCW) systems in advanced power generation and reactor designs operate under extreme conditions where strong property gradients can induce flow instabilities, affecting efficiency, safety, and reliability; however, experimental data for inclined tubes remain scarce due to testing challenges. Most studies on supercritical fluids assume uniform heating around the tube, an approach often impractical in real-world applications. This study addresses this limitation by analyzing the effect of non-uniform heating on flow instability in SCW within inclined tubes (0°-90°) under different operating conditions, such as pressure, inlet temperature (<em>T</em><sub>in</sub>), heat flux, and mass flow rate. Higher pressure and mass flow rate significantly enhance stability. Similarly, the higher the <em>T</em><sub>in</sub> enhances stability, with 573 K reducing fluctuations by ∼40% compared to 493 K. Higher heat flux generally stabilizes the flow at lower angles; it intensifies instability at higher inclination angles. Vertical orientation consistently shows the highest instability. These findings provide critical insights into the design and optimization of supercritical thermal systems, emphasizing the importance of integrated control of thermal, flow, and operating parameters to ensure stable and efficient operations.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110587"},"PeriodicalIF":6.4,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073844","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 : 2026-01-27DOI: 10.1016/j.icheatmasstransfer.2026.110572
Linzhi Yin , Xin Sun , Hesam Naseri , S. Mohammad Sajadi , Mustafa Bayram , Majed M. Alghamdi
This study uniquely investigated the impact of nitrogen doping on the mechanical stability, structural deformation, and energetic properties of carbon nanotubes (CNTs) through non-equilibrium molecular dynamics simulations, systematically varying nitrogen doping concentrations (5%, 10%, 15%, 20%, 25%, and 30%). Unlike prior studies that mainly focused on electronic or catalytic effects, this work provides new atomic-level insights into how nitrogen doping alters the mechanical response of CNTs during buckling. We analyzed the evolution of kinetic energy, potential energy, the center of mass (COM), mean-squared displacement (MSD), and interaction energy throughout the simulations. Our results demonstrate that increased nitrogen doping led to higher atomic mobility and structural disorder, as indicated by elevated kinetic energy and MSD values both before and after buckling. The potential energy profiles showed that nitrogen-rich nanotubes adopted lower-energy configurations, reflecting diminished structural stability. COM analysis revealed that higher doping levels hindered global structural shifts during deformation, indicating that buckling occurred through localized, severe kinks rather than uniform bending. Contrary to expectations, interaction energy remained largely unaffected by nitrogen doping, suggesting that doping primarily affected structural dynamics rather than atomic interaction energy. These findings confirmed that nitrogen doping destabilized the CNT structure, increasing susceptibility to mechanical deformation. This comprehensive exploration of mechanical and dynamic effects distinguished our work, offering critical insights for designing nitrogen-doped CNTs in nanotechnology applications where mechanical integrity is pivotal.
{"title":"Investigating the effect of nitrogen doping on the buckling process of carbon nanotubes using non-equilibrium molecular dynamics simulation","authors":"Linzhi Yin , Xin Sun , Hesam Naseri , S. Mohammad Sajadi , Mustafa Bayram , Majed M. Alghamdi","doi":"10.1016/j.icheatmasstransfer.2026.110572","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110572","url":null,"abstract":"<div><div>This study uniquely investigated the impact of nitrogen doping on the mechanical stability, structural deformation, and energetic properties of carbon nanotubes (CNTs) through non-equilibrium molecular dynamics simulations, systematically varying nitrogen doping concentrations (5%, 10%, 15%, 20%, 25%, and 30%). Unlike prior studies that mainly focused on electronic or catalytic effects, this work provides new atomic-level insights into how nitrogen doping alters the mechanical response of CNTs during buckling. We analyzed the evolution of kinetic energy, potential energy, the center of mass (COM), mean-squared displacement (MSD), and interaction energy throughout the simulations. Our results demonstrate that increased nitrogen doping led to higher atomic mobility and structural disorder, as indicated by elevated kinetic energy and MSD values both before and after buckling. The potential energy profiles showed that nitrogen-rich nanotubes adopted lower-energy configurations, reflecting diminished structural stability. COM analysis revealed that higher doping levels hindered global structural shifts during deformation, indicating that buckling occurred through localized, severe kinks rather than uniform bending. Contrary to expectations, interaction energy remained largely unaffected by nitrogen doping, suggesting that doping primarily affected structural dynamics rather than atomic interaction energy. These findings confirmed that nitrogen doping destabilized the CNT structure, increasing susceptibility to mechanical deformation. This comprehensive exploration of mechanical and dynamic effects distinguished our work, offering critical insights for designing nitrogen-doped CNTs in nanotechnology applications where mechanical integrity is pivotal.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110572"},"PeriodicalIF":6.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073835","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 : 2026-01-27DOI: 10.1016/j.icheatmasstransfer.2026.110621
Muhammad Idrees Afridi , Amra Al Kenany , Sultan Alshehery , Hussain Sawwan , Naif Almakayeel , Ali Alamry , Nemat Mashoofi Maleki , Saman Pourahmad
Efficient thermal management has become a critical bottleneck for next-generation high-power electronic devices, as conventional single-phase cooling techniques struggle to maintain performance under rising thermal design powers (TDPs). While microchannel cold plates improve heat dissipation by increasing the surface area and disrupting boundary layers, their performance is still constrained under high thermal loads, particularly with next-generation chips that have TDPs exceeding 700 W. To address this limitation, this study proposes a hybrid cooling strategy that integrates microchannel cold plates with active bubble injection. In the first phase of the study, baseline tests at TDPs of 560–800 W and flow rates of 0.5–1.5 l/min showed that microchanneling reduced surface temperature by up to 14.6 °C and thermal resistance by 18.6% compared with smooth plates. In the second phase, air was injected through one to five outlet branches at a constant rate of 0.2 l/min to identify the optimal configuration using the thermal performance factor (TP). The effect of air injection rate (0.2–1 l/min) was then examined. The optimal hydrothermal condition (TP = 1.2) occurred with four branches and an injection rate of 0.4 l/min, yielding a 20.1 °C temperature reduction, a 43% enhancement in the Nusselt number, and a 25.5% drop in thermal resistance compared to the plain cold plate. The energy reuse potential of this method was assessed alongside the hydrothermal performance. Results show that integrating recycled data-center energy can raise the Energy Reuse Factor (ERF) by up to 84% without exceeding safe chip temperatures, demonstrating strong applicability for next-generation high-power CPU cooling systems.
{"title":"Enhancing the thermal performance of microchannel cold plates via controlled bubble injection for next-generation high-power electronic chips","authors":"Muhammad Idrees Afridi , Amra Al Kenany , Sultan Alshehery , Hussain Sawwan , Naif Almakayeel , Ali Alamry , Nemat Mashoofi Maleki , Saman Pourahmad","doi":"10.1016/j.icheatmasstransfer.2026.110621","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110621","url":null,"abstract":"<div><div>Efficient thermal management has become a critical bottleneck for next-generation high-power electronic devices, as conventional single-phase cooling techniques struggle to maintain performance under rising thermal design powers (TDPs). While microchannel cold plates improve heat dissipation by increasing the surface area and disrupting boundary layers, their performance is still constrained under high thermal loads, particularly with next-generation chips that have TDPs exceeding 700 W. To address this limitation, this study proposes a hybrid cooling strategy that integrates microchannel cold plates with active bubble injection. In the first phase of the study, baseline tests at TDPs of 560–800 W and flow rates of 0.5–1.5 <em>l/</em>min showed that microchanneling reduced surface temperature by up to 14.6 °C and thermal resistance by 18.6% compared with smooth plates. In the second phase, air was injected through one to five outlet branches at a constant rate of 0.2 <em>l/</em>min to identify the optimal configuration using the thermal performance factor (TP). The effect of air injection rate (0.2–1 <em>l/min</em>) was then examined. The optimal hydrothermal condition (TP = 1.2) occurred with four branches and an injection rate of 0.4 <em>l/min</em>, yielding a 20.1 °C temperature reduction, a 43% enhancement in the Nusselt number, and a 25.5% drop in thermal resistance compared to the plain cold plate. The energy reuse potential of this method was assessed alongside the hydrothermal performance. Results show that integrating recycled data-center energy can raise the Energy Reuse Factor (ERF) by up to 84% without exceeding safe chip temperatures, demonstrating strong applicability for next-generation high-power CPU cooling systems.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110621"},"PeriodicalIF":6.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073867","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 : 2026-01-27DOI: 10.1016/j.icheatmasstransfer.2026.110628
Pradip Roul, Sameer N. Khandagale, Vikas Kumar
In this study, we introduce a fast and high-order numerical method to solve the two-dimensional Caputo time-fractional convection–reaction–diffusion problem. We present a numerical technique that combines the L2–1 scheme for temporal discretization with a compact finite difference method for spatial discretization. Since the model exhibits a weak singularity near the initial time, a graded temporal mesh is adopted to handle this behavior, which provides a accuracy of order in temporal direction. As the fully discrete scheme incurs high computational cost, the fast discrete sine transform is adopted to achieve a significant reduction in cost. Furthermore, the global -norm stability and -norm convergence of the proposed method are rigorously established. Numerical experiments are carried out to demonstrate the accuracy of the present method. The proposed graded mesh scheme is shown to outperform existing methods Roul (2022) and Kumari (2024) in terms of accuracy and efficiency.
{"title":"A fast and accurate discrete sine transform method for two-dimensional time-fractional convection–reaction–diffusion equations","authors":"Pradip Roul, Sameer N. Khandagale, Vikas Kumar","doi":"10.1016/j.icheatmasstransfer.2026.110628","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110628","url":null,"abstract":"<div><div>In this study, we introduce a fast and high-order numerical method to solve the two-dimensional Caputo time-fractional convection–reaction–diffusion problem. We present a numerical technique that combines the L2–1<span><math><msub><mrow></mrow><mrow><mi>σ</mi></mrow></msub></math></span> scheme for temporal discretization with a compact finite difference method for spatial discretization. Since the model exhibits a weak singularity near the initial time, a graded temporal mesh is adopted to handle this behavior, which provides a accuracy of order <span><math><mrow><mo>min</mo><mrow><mo>{</mo><mi>r</mi><mi>α</mi><mo>,</mo><mn>2</mn><mo>}</mo></mrow></mrow></math></span> in temporal direction. As the fully discrete scheme incurs high computational cost, the fast discrete sine transform is adopted to achieve a significant reduction in cost. Furthermore, the global <span><math><msup><mrow><mi>H</mi></mrow><mrow><mn>1</mn></mrow></msup></math></span>-norm stability and <span><math><msup><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>-norm convergence of the proposed method are rigorously established. Numerical experiments are carried out to demonstrate the accuracy of the present method. The proposed graded mesh scheme is shown to outperform existing methods Roul (2022) and Kumari (2024) in terms of accuracy and efficiency.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110628"},"PeriodicalIF":6.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073840","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 : 2026-01-27DOI: 10.1016/j.icheatmasstransfer.2026.110622
Yonghong Wu , Yongbo Li , Pingwei Qin , Chao Yang , Yuxin Chen , Zhiyong Wang , Yunfei Yan , Shihong Wei , Mingjiang Xu , Chenghua Zhang
Ensuring a uniform thermo-flow field in intensive curing barns is critical to the curing of tobacco leave. This study proposes a perforated horizontal plate with stepped-spacing openings to regulate interlayer airflow and alleviate inlet-side stagnation. First, the composite thermo-flow performance is evaluated for different opening diameters (d). As d increases, performance initially improves and then deteriorates, d = 250 mm is optimal, reducing the maximum interlayer temperature difference () and temperature standard deviation (TSD) by 10.86 K and 4.89 K, respectively, and increasing the interlayer mean temperature by 4.61 K. Next, the opening ratio (φ) is optimized. Increasing φ generally enhances performance, φ = 0.28 offers the best compromise, further decreasing in full-cycle to 9.01, 7.49, and 4.07 K. Compared with φ = 0.12 in the fixative period, each layer TSD decrease by 1.08, 1.43, and 0.97 K. Introducing stepped spacing (150/200/250 mm) provides further improvements over uniform spacing, decreasing the interlayer TSD to 0.42, 0.19, and 0.02 K in the yellowing period and reducing full-cycle by an additional 1.81, 1.63, and 0.33 K, respectively. These insights provide a practical guidance for airflow allocation and structural optimization in intensive curing barns.
{"title":"Enhancing full-cycle thermo-flow uniformity in intensive curing barns via perforated horizontal plates with stepped spacing","authors":"Yonghong Wu , Yongbo Li , Pingwei Qin , Chao Yang , Yuxin Chen , Zhiyong Wang , Yunfei Yan , Shihong Wei , Mingjiang Xu , Chenghua Zhang","doi":"10.1016/j.icheatmasstransfer.2026.110622","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110622","url":null,"abstract":"<div><div>Ensuring a uniform thermo-flow field in intensive curing barns is critical to the curing of tobacco leave. This study proposes a perforated horizontal plate with stepped-spacing openings to regulate interlayer airflow and alleviate inlet-side stagnation. First, the composite thermo-flow performance is evaluated for different opening diameters (d). As d increases, performance initially improves and then deteriorates, d = 250 mm is optimal, reducing the maximum interlayer temperature difference (<span><math><mi>Δ</mi><msub><mi>T</mi><mi>max</mi></msub></math></span>) and temperature standard deviation (TSD) by 10.86 K and 4.89 K, respectively, and increasing the interlayer mean temperature by 4.61 K. Next, the opening ratio (φ) is optimized. Increasing φ generally enhances performance, φ = 0.28 offers the best compromise, further decreasing <span><math><mi>Δ</mi><msub><mi>T</mi><mi>max</mi></msub></math></span> in full-cycle to 9.01, 7.49, and 4.07 K. Compared with φ = 0.12 in the fixative period, each layer TSD decrease by 1.08, 1.43, and 0.97 K. Introducing stepped spacing (150/200/250 mm) provides further improvements over uniform spacing, decreasing the interlayer TSD to 0.42, 0.19, and 0.02 K in the yellowing period and reducing full-cycle <span><math><mi>Δ</mi><msub><mi>T</mi><mi>max</mi></msub></math></span> by an additional 1.81, 1.63, and 0.33 K, respectively. These insights provide a practical guidance for airflow allocation and structural optimization in intensive curing barns.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110622"},"PeriodicalIF":6.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073926","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 : 2026-01-27DOI: 10.1016/j.icheatmasstransfer.2026.110540
Amin Shahsavar , Arian Pourvali , Mahan Hasani
In this study, the thermal performance and entropy generation behavior of a heat sink equipped with multilayer phase change materials and copper pin fins under constant heat flux are numerically investigated. Five separator materials with different thermal conductivities (copper, aluminum, stainless steel, alumina, and epoxy) are examined in 25 configurations, including symmetric arrangements with identical separator materials (A1–A5) and asymmetric configurations with different materials used for the lower and upper separators (B1–B20). A three-dimensional transient enthalpy-porosity model is used to analyze melting dynamics, temperature distribution, and the evolution of thermal and frictional entropies. The results show that separator conductivity has little effect on melting time or the overall temperature trend but strongly influences both the magnitude and pattern of entropy generation. In symmetric configurations, changing separator conductivity alters only the entropy magnitude. In asymmetric arrangements, the sequence of conductive and nonconductive layers plays a dominant role. A conductive bottom separator combined with a moderately conductive top layer yields the lowest entropy generation, whereas a nonconductive bottom separator increases thermal entropy by up to 35% and frictional entropy by more than 50%. Local contours further reveal that conductivity discontinuities intensify temperature and velocity gradients, forming concentrated irreversible regions.
{"title":"Impact of separator conductivity on thermal performance and irreversibility in multilayer phase change material heat sinks","authors":"Amin Shahsavar , Arian Pourvali , Mahan Hasani","doi":"10.1016/j.icheatmasstransfer.2026.110540","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110540","url":null,"abstract":"<div><div>In this study, the thermal performance and entropy generation behavior of a heat sink equipped with multilayer phase change materials and copper pin fins under constant heat flux are numerically investigated. Five separator materials with different thermal conductivities (copper, aluminum, stainless steel, alumina, and epoxy) are examined in 25 configurations, including symmetric arrangements with identical separator materials (A1–A5) and asymmetric configurations with different materials used for the lower and upper separators (B1–B20). A three-dimensional transient enthalpy-porosity model is used to analyze melting dynamics, temperature distribution, and the evolution of thermal and frictional entropies. The results show that separator conductivity has little effect on melting time or the overall temperature trend but strongly influences both the magnitude and pattern of entropy generation. In symmetric configurations, changing separator conductivity alters only the entropy magnitude. In asymmetric arrangements, the sequence of conductive and nonconductive layers plays a dominant role. A conductive bottom separator combined with a moderately conductive top layer yields the lowest entropy generation, whereas a nonconductive bottom separator increases thermal entropy by up to 35% and frictional entropy by more than 50%. Local contours further reveal that conductivity discontinuities intensify temperature and velocity gradients, forming concentrated irreversible regions.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110540"},"PeriodicalIF":6.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073995","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 : 2026-01-27DOI: 10.1016/j.icheatmasstransfer.2026.110605
Pooja , Paras Ram , B.C. Prasannakumara
This research investigates ferrofluid-based squeeze-film lubrications in the Kozeny-Carman porous framework for a variety of bearing geometries, such as secant, exponential, parallel, convex, and inclined pads. The Kozeny-Carman globular-sphere description describes the porous surface, and Jenkins' model is used to compute the mean temperature. Porosity, slip, and material qualities are taken into account when determining load capacity, average temperature, and pressure-center behaviour. Additionally, it fills in the gaps between porous tribology and magnetic lubricating technology. The ferroliquid is considered incompressible, and its viscosity varies with temperature. The effects of modifying bearing properties on pressure fields, load performance, and thermal behaviour are graphically depicted. The corotational derivative of magnetization is essential for pressure-supporting systems, and higher slip lowers the temperature. When thermal variations are taken into account, the study shows the 17.11% increase in load capability and the 12% decrease in temperature, for the performance enhancement of 2.81%. These data show that the convex pad works better in low-slip situations, while the inclined pad operates more effectively in moderate-slip situations. The inclined slider bearing is the best choice after taking all thermal factors into account. When all thermal considerations have been considered, the inclined slider bearing is recommended.
{"title":"A comparative analysis of pressure centroid and thermal interactions within the Kozeny-Carman architecture across a spectrum of bearing configuration under transient dynamic regimes","authors":"Pooja , Paras Ram , B.C. Prasannakumara","doi":"10.1016/j.icheatmasstransfer.2026.110605","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110605","url":null,"abstract":"<div><div>This research investigates ferrofluid-based squeeze-film lubrications in the Kozeny-Carman porous framework for a variety of bearing geometries, such as secant, exponential, parallel, convex, and inclined pads. The Kozeny-Carman globular-sphere description describes the porous surface, and Jenkins' model is used to compute the mean temperature. Porosity, slip, and material qualities are taken into account when determining load capacity, average temperature, and pressure-center behaviour. Additionally, it fills in the gaps between porous tribology and magnetic lubricating technology. The ferroliquid is considered incompressible, and its viscosity varies with temperature. The effects of modifying bearing properties on pressure fields, load performance, and thermal behaviour are graphically depicted. The corotational derivative of magnetization is essential for pressure-supporting systems, and higher slip lowers the temperature. When thermal variations are taken into account, the study shows the 17.11% increase in load capability and the 12% decrease in temperature, for the performance enhancement of 2.81%. These data show that the convex pad works better in low-slip situations, while the inclined pad operates more effectively in moderate-slip situations. The inclined slider bearing is the best choice after taking all thermal factors into account. When all thermal considerations have been considered, the inclined slider bearing is recommended.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110605"},"PeriodicalIF":6.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074098","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}
The main goal of this study is to create a single fractional thermoelastic–machine learning framework that can accurately model how heat and stress move through skin tissue over time and automatically sort thermal regimes into safe and dangerous ones. The proposed method combines the Atangana–Baleanu fractional operator with the Cattaneo–Vernotte heat flux law and data-driven classifiers (KNN, SVM, and CNN), and Laplace Transforms techniques to derive generalized thermoelastic formulations capable of capturing finite-speed thermal propagation, memory effects, and nonlocal stress relaxation. This connects strict analytical modeling with smart thermal safety prediction. Closed-form expressions for temperature, displacement, dilation, and stress fields are obtained in the Laplace domain and numerically inverted to evaluate transient responses under thermal shock. All fractional thermoelastic simulations and Laplace inversions were executed in MATLAB R2023a, whereas the machine-learning models (KNN, SVM, CNN) were implemented in Python 3.10 using scikit-learn and TensorFlow. To extend the predictive capacity of the analytical models, simulation-derived datasets are used to train three machine learning classifiers—K-Nearest Neighbors (KNN), Support Vector Machine (SVM), and Convolutional Neural Network (CNN). Comparative analyses through confusion matrices, dispersion maps, ROC curves, residual maps, and bar charts demonstrate that CNN achieves superior nonlinear feature extraction and generalization, SVM provides stable global decision boundaries, and KNN efficiently identifies localized thermal–mechanical anomalies. The AB fractional model is shown to suppress temperature overshoot and reduce stress concentration relative to CV, offering safer predictions for biological tissues. The combined fractional–ML framework enables rapid classification of safe and risky heating regimes, with potential applications in hyperthermia therapy, burn injury prevention, dermatological laser treatments, and thermal hotspot detection in engineered composites. This study establishes a unified pathway where fractional thermoelastic modeling, deep learning, and classical machine learning synergistically addresses complex biomedical and material thermal interactions. A synthetic dataset generated from fractional AB–CV thermoelastic simulations was used for training the ML classifiers.
这项研究的主要目标是创建一个单一的分数热弹性机器学习框架，该框架可以准确地模拟热量和应力如何随着时间的推移在皮肤组织中移动，并自动将热状态分为安全和危险的状态。该方法将Atangana-Baleanu分数算子与Cattaneo-Vernotte热通量定律、数据驱动分类器（KNN、SVM和CNN）和拉普拉斯变换技术结合起来，推导出能够捕捉有限速度热传播、记忆效应和非局部应力松弛的广义热弹性公式。这将严格的分析建模与智能热安全预测联系起来。在拉普拉斯域中得到了温度、位移、膨胀和应力场的封闭表达式，并进行了数值反演，以评估热冲击下的瞬态响应。所有分数热弹性模拟和拉普拉斯反演都在MATLAB R2023a中执行，而机器学习模型（KNN， SVM， CNN）则在Python 3.10中使用scikit-learn和TensorFlow实现。为了扩展分析模型的预测能力，模拟衍生的数据集用于训练三种机器学习分类器- k -近邻（KNN），支持向量机（SVM）和卷积神经网络（CNN）。通过混淆矩阵、色散图、ROC曲线、残差图和柱状图的对比分析表明，CNN在非线性特征提取和泛化方面取得了优异的成绩，SVM提供了稳定的全局决策边界，KNN有效地识别了局部热-机械异常。与CV相比，AB分数模型可以抑制温度超调，降低应力浓度，为生物组织提供更安全的预测。结合分数- ml框架可以快速分类安全和危险的加热制度，在热疗、烧伤预防、皮肤激光治疗和工程复合材料的热热点检测方面具有潜在的应用前景。本研究建立了一个统一的途径，其中分数热弹性建模，深度学习和经典机器学习协同解决复杂的生物医学和材料热相互作用。由分数AB-CV热弹性模拟生成的合成数据集用于训练ML分类器。
{"title":"Hybrid fractional thermoelastic–machine learning (KNN, CNN and SVM classifier) framework for heat and mass transfer: A computational mechanics approach","authors":"Seema , Abhinav Singhal , Abdulkafi Mohammed Saeed , Sonal Nirwal , Anjali Chaudhary","doi":"10.1016/j.icheatmasstransfer.2026.110623","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110623","url":null,"abstract":"<div><div>The main goal of this study is to create a single fractional thermoelastic–machine learning framework that can accurately model how heat and stress move through skin tissue over time and automatically sort thermal regimes into safe and dangerous ones. The proposed method combines the Atangana–Baleanu fractional operator with the Cattaneo–Vernotte heat flux law and data-driven classifiers (KNN, SVM, and CNN), and Laplace Transforms techniques to derive generalized thermoelastic formulations capable of capturing finite-speed thermal propagation, memory effects, and nonlocal stress relaxation. This connects strict analytical modeling with smart thermal safety prediction. Closed-form expressions for temperature, displacement, dilation, and stress fields are obtained in the Laplace domain and numerically inverted to evaluate transient responses under thermal shock. All fractional thermoelastic simulations and Laplace inversions were executed in MATLAB R2023a, whereas the machine-learning models (KNN, SVM, CNN) were implemented in Python 3.10 using scikit-learn and TensorFlow. To extend the predictive capacity of the analytical models, simulation-derived datasets are used to train three machine learning classifiers—K-Nearest Neighbors (KNN), Support Vector Machine (SVM), and Convolutional Neural Network (CNN). Comparative analyses through confusion matrices, dispersion maps, ROC curves, residual maps, and bar charts demonstrate that CNN achieves superior nonlinear feature extraction and generalization, SVM provides stable global decision boundaries, and KNN efficiently identifies localized thermal–mechanical anomalies. The AB fractional model is shown to suppress temperature overshoot and reduce stress concentration relative to CV, offering safer predictions for biological tissues. The combined fractional–ML framework enables rapid classification of safe and risky heating regimes, with potential applications in hyperthermia therapy, burn injury prevention, dermatological laser treatments, and thermal hotspot detection in engineered composites. This study establishes a unified pathway where fractional thermoelastic modeling, deep learning, and classical machine learning synergistically addresses complex biomedical and material thermal interactions. A synthetic dataset generated from fractional AB–CV thermoelastic simulations was used for training the ML classifiers.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110623"},"PeriodicalIF":6.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073871","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 : 2026-01-27DOI: 10.1016/j.icheatmasstransfer.2026.110618
Zhentao Wang , Changyu Zhong , Lingshuo Chen , Xiaodong Guo , Yuzhen Zhao , Xuan Zhang
To address the degradation of heat transfer during the solidification of phase change materials (PCMs), caused by their low thermal conductivity and the increasing thermal resistance of the solidified layer, this study experimentally investigates the coupled effects of rotation angle and rotation interval on the solidification performance, temperature uniformity, and underlying heat transfer enhancement mechanisms in a rotating latent heat storage (LHS) unit. An active rotation experimental setup was designed and constructed. By varying the rotation angle and interval, the transient temperature field, heat release rate, and complete solidification time during PCM solidification were measured and compared. Experimental results demonstrate that rotation significantly improves solidification performance. Compared with the static case, the temperature uniformity index of the storage system was reduced by 55%, and the instantaneous heat release rate could reach up to 4.5 times that under static conditions. Among the tested parameters, the average heat release rate achieved with 90° rotation in the later stage was 2.7 times higher than that with 45° rotation. Through contour analysis, an optimized operation scheme is proposed. During the initial solidification stage, shorter intervals (120–150 s) combined with moderate angles (60–70°) are applied to disrupt thermal stratification; in the later stage, longer intervals (160–190 s) with larger angles (70–80°) are adopted to promote uniform solidification, thereby enhancing overall efficiency. This work not only clarifies the coupled influence mechanisms of rotation parameters on the PCM solidification process, but also provides a novel and operable thermal management strategy for designing high-performance active latent heat storage systems.
{"title":"Parametric optimization of rotational enhancement for solidification in latent heat storage","authors":"Zhentao Wang , Changyu Zhong , Lingshuo Chen , Xiaodong Guo , Yuzhen Zhao , Xuan Zhang","doi":"10.1016/j.icheatmasstransfer.2026.110618","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110618","url":null,"abstract":"<div><div>To address the degradation of heat transfer during the solidification of phase change materials (PCMs), caused by their low thermal conductivity and the increasing thermal resistance of the solidified layer, this study experimentally investigates the coupled effects of rotation angle and rotation interval on the solidification performance, temperature uniformity, and underlying heat transfer enhancement mechanisms in a rotating latent heat storage (LHS) unit. An active rotation experimental setup was designed and constructed. By varying the rotation angle and interval, the transient temperature field, heat release rate, and complete solidification time during PCM solidification were measured and compared. Experimental results demonstrate that rotation significantly improves solidification performance. Compared with the static case, the temperature uniformity index of the storage system was reduced by 55%, and the instantaneous heat release rate could reach up to 4.5 times that under static conditions. Among the tested parameters, the average heat release rate achieved with 90° rotation in the later stage was 2.7 times higher than that with 45° rotation. Through contour analysis, an optimized operation scheme is proposed. During the initial solidification stage, shorter intervals (120–150 s) combined with moderate angles (60–70°) are applied to disrupt thermal stratification; in the later stage, longer intervals (160–190 s) with larger angles (70–80°) are adopted to promote uniform solidification, thereby enhancing overall efficiency. This work not only clarifies the coupled influence mechanisms of rotation parameters on the PCM solidification process, but also provides a novel and operable thermal management strategy for designing high-performance active latent heat storage systems.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110618"},"PeriodicalIF":6.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074099","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}
The purpose of this computational work is to investigate the transport phenomena associated with vectored annular jets impinging on heated surface. The study takes into account jet Reynolds numbers in the range of 100 to 5000 and the transition-SST (shear–stress transport) model is used to resolve the flow field. After the computational model has been validated, detailed flow structure and thermal field has been evaluated. Topology of skin friction lines for three dimensional vectored jets with instinct flow pattern is observed and detailed quantification of thermal filed is carried out by calculating local and surface-averaged Nusselt number. There is a strong relationship between the Reynolds number and the strength, shape and size of the recirculation zone that exists within the flow domain. Additionally, turbulence plays a significant role in the enhancement of heat transfer within the impingement zone, which is especially visible at higher Reynolds numbers. The model is found to aid in identifying the transition to turbulence for vectored annular jets.
{"title":"Computational analysis of vectored annular jet impingement on a heated surface: Flow dynamics and heat transfer characteristics","authors":"Abhik Adhikari , Sudipta Basak , Prasun Dutta , Himadri Chattopadhyay","doi":"10.1016/j.icheatmasstransfer.2026.110638","DOIUrl":"10.1016/j.icheatmasstransfer.2026.110638","url":null,"abstract":"<div><div>The purpose of this computational work is to investigate the transport phenomena associated with vectored annular jets impinging on heated surface. The study takes into account jet Reynolds numbers in the range of 100 to 5000 and the transition-SST (shear–stress transport) model is used to resolve the flow field. After the computational model has been validated, detailed flow structure and thermal field has been evaluated. Topology of skin friction lines for three dimensional vectored jets with instinct flow pattern is observed and detailed quantification of thermal filed is carried out by calculating local and surface-averaged Nusselt number. There is a strong relationship between the Reynolds number and the strength, shape and size of the recirculation zone that exists within the flow domain. Additionally, turbulence plays a significant role in the enhancement of heat transfer within the impingement zone, which is especially visible at higher Reynolds numbers. The model is found to aid in identifying the transition to turbulence for vectored annular jets.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"172 ","pages":"Article 110638"},"PeriodicalIF":6.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074105","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号