Pub Date : 2026-01-23DOI: 10.1016/j.ijheatmasstransfer.2026.128405
Andrey A. Chernov , Dmitrii V. Antonov , Pavel A. Strizhak , Sergei S. Sazhin
A model for the start of the nucleation process during liquid overheating, based on the kinetic theory of phase transformation, is developed and applied to the analysis of puffing/micro-explosion in composite water/n-dodecane droplets. The contributions of homogeneous and heterogeneous nucleations, both of which are mainly controlled by the free energy of the formation of a critical nucleus, are considered. The nucleation temperature is identified as the maximal temperature in the volume in which the nucleation process starts. The heterogeneous nucleation rate is shown to be a strong function of the wetting angle at the surfaces of the particles that are the sources of heterogeneity. The sensitivity of the nucleation rate to this angle is shown to lead to the sensitivity of the predicted nucleation temperature to this angle. This temperature is shown to be a weak function of the rate of temperature change for homogeneous and heterogeneous nucleation. It is shown that, for real-life values of input parameters, the predicted nucleation temperatures are reasonably close to those inferred from experimental data, both original in-house and previously published. The new model allows us to gain new insight into the physical background of the phenomenon.
{"title":"The start of the nucleation process in heated composite droplets: A semi-analytical model","authors":"Andrey A. Chernov , Dmitrii V. Antonov , Pavel A. Strizhak , Sergei S. Sazhin","doi":"10.1016/j.ijheatmasstransfer.2026.128405","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128405","url":null,"abstract":"<div><div>A model for the start of the nucleation process during liquid overheating, based on the kinetic theory of phase transformation, is developed and applied to the analysis of puffing/micro-explosion in composite water/n-dodecane droplets. The contributions of homogeneous and heterogeneous nucleations, both of which are mainly controlled by the free energy of the formation of a critical nucleus, are considered. The nucleation temperature is identified as the maximal temperature in the volume in which the nucleation process starts. The heterogeneous nucleation rate is shown to be a strong function of the wetting angle at the surfaces of the particles that are the sources of heterogeneity. The sensitivity of the nucleation rate to this angle is shown to lead to the sensitivity of the predicted nucleation temperature to this angle. This temperature is shown to be a weak function of the rate of temperature change <span><math><mfenced><mrow><mi>d</mi><mi>T</mi><mo>/</mo><mi>d</mi><mi>t</mi></mrow></mfenced></math></span> for homogeneous and heterogeneous nucleation. It is shown that, for real-life values of input parameters, the predicted nucleation temperatures are reasonably close to those inferred from experimental data, both original in-house and previously published. The new model allows us to gain new insight into the physical background of the phenomenon.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128405"},"PeriodicalIF":5.8,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146015851","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 : 2026-01-23DOI: 10.1016/j.ijheatmasstransfer.2026.128428
Xincheng Yang , Kuangrong Hao , Chenyang Meng , Xian Qi , Lei Chen , Yan Cheng
Microwave heating often exhibits nonuniform temperature distributions due to standing wave patterns and material property variations, limiting its industrial applicability. Existing models rely on idealized assumptions and static boundaries, which prevents them from accurately predicting temperature evolution under dynamic conditions. To address this, we propose a novel neural network framework featuring a Heat Source Estimator (HSE) and a Thermal Diffusion Operator (TDO). Unlike conventional Physics-Informed Neural Networks (PINNs) that impose governing equations as soft constraints in the loss function, our approach embeds the heat conduction law as a structural inductive bias, achieving greater flexibility and efficiency while preserving physical interpretability. Furthermore, we build the Microwave Heating Spatiotemporal Dataset (MHSTD) via infrared thermography to document thermal dynamics across varying materials. Compared to the state-of-the-art TAU model, our method reduces the RMSE by 5.3% in standard benchmarks and by 43.5% in cross-domain generalization tests. This work establishes a new paradigm for spatiotemporal prediction in microwave heating, providing a high-performance predictive foundation for the optimization of heating processes.
{"title":"Physics-guided neural networks for microwave heating temperature field prediction","authors":"Xincheng Yang , Kuangrong Hao , Chenyang Meng , Xian Qi , Lei Chen , Yan Cheng","doi":"10.1016/j.ijheatmasstransfer.2026.128428","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128428","url":null,"abstract":"<div><div>Microwave heating often exhibits nonuniform temperature distributions due to standing wave patterns and material property variations, limiting its industrial applicability. Existing models rely on idealized assumptions and static boundaries, which prevents them from accurately predicting temperature evolution under dynamic conditions. To address this, we propose a novel neural network framework featuring a Heat Source Estimator (HSE) and a Thermal Diffusion Operator (TDO). Unlike conventional Physics-Informed Neural Networks (PINNs) that impose governing equations as soft constraints in the loss function, our approach embeds the heat conduction law as a structural inductive bias, achieving greater flexibility and efficiency while preserving physical interpretability. Furthermore, we build the Microwave Heating Spatiotemporal Dataset (MHSTD) via infrared thermography to document thermal dynamics across varying materials. Compared to the state-of-the-art TAU model, our method reduces the RMSE by 5.3% in standard benchmarks and by 43.5% in cross-domain generalization tests. This work establishes a new paradigm for spatiotemporal prediction in microwave heating, providing a high-performance predictive foundation for the optimization of heating processes.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128428"},"PeriodicalIF":5.8,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026031","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 : 2026-01-23DOI: 10.1016/j.ijheatmasstransfer.2026.128396
Prashant Saini , Julian D. Osorio , Ruhanii Avula
<div><div>Fin-and-tube heat exchangers (FTHEs) are widely used for high-temperature flue-gas heat recovery, but their performance is often limited by wake regions and non-uniform fin-surface temperatures. This study proposes and numerically evaluates four bio-inspired longitudinal vortex generator (VG) configurations in a high-temperature FTHE with flue-gas inlet temperature ∼1230 K: double-delta, curved double-delta, alula, and a new curved-alula geometry. The reference fin is not hydraulically plain; it already incorporates leading-edge separation columns and convex protrusions, so the alula-type winglets are assessed as downstream add-ons acting on a strongly disturbed flow. In a second step, perforations (one, two and three circular holes) are introduced into the curved-alula VGs to further tailor the flow field. Three-dimensional simulations with the Shear Stress Transpor (SST) <span><math><mrow><mi>k</mi><mo>−</mo><mi>ω</mi></mrow></math></span> model, temperature-dependent flue-gas properties and conjugate conduction are carried out for gas-side Reynolds numbers <span><math><mrow><mi>R</mi><msub><mi>e</mi><mi>g</mi></msub><mo>≈</mo><mn>8.0</mn><mspace></mspace><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>2</mn></msup></mrow></math></span> – <span><math><mrow><mn>3.6</mn><mspace></mspace><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>3</mn></msup></mrow></math></span> (mass flow rates 0.5 – 2.5 g/s), and the designs are compared in terms of surface heat flux, Nusselt number, friction factor and hydrothermal performance factor (HTPF). For this already-promoted fin, the additional downstream winglets provide moderate, incremental hydrothermal gains. At the highest Reynolds number, the best non-perforated design (curved-alula) increases surface heat flux from 1630.9 to 1794.7 kW/m² (∼ 10 % gain) and the Nusselt number from 227.6 to 242.6 (∼ 7 % gain), while the friction factor rises from 0.26 to about 0.30, yielding HTPF values close to unity (∼ 0.9 – 1.0). Introducing circular perforations into the curved-alula winglets acts mainly as a wake-bleeding refinement: the three-hole configuration provides a heat flux of 1824.7 kW/m² and a pressure drop of 127.9 Pa, with HTPF in the range ∼ 1.03 – 1.14 and a small (∼ 1 – 3 %) improvement over the solid curved-alula design. Flow-field analysis shows that the perforated curved-alula VGs shrink tube-wake regions, thin the thermal boundary layer and homogenize the fin-surface temperature (outlet-gas temperature ∼ 510 – 520 K and fin-surface temperature ∼ 420 – 421 K for the three-hole case). An optimal flue-gas mass flow rate of ∼ 1 g/s (<span><math><mrow><mi>R</mi><msub><mi>e</mi><mi>g</mi></msub><mo>≈</mo><mn>1.5</mn><mspace></mspace><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>3</mn></msup></mrow></math></span>) is identified, beyond which additional heat-transfer gains are offset by rapidly increasing pressure losses. Overall, the results highlight that initial fin geometry and VG placement are as import
{"title":"Bio-inspired alula-based winglet design for enhanced heat transfer in high temperature fin-and-tube heat exchangers","authors":"Prashant Saini , Julian D. Osorio , Ruhanii Avula","doi":"10.1016/j.ijheatmasstransfer.2026.128396","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128396","url":null,"abstract":"<div><div>Fin-and-tube heat exchangers (FTHEs) are widely used for high-temperature flue-gas heat recovery, but their performance is often limited by wake regions and non-uniform fin-surface temperatures. This study proposes and numerically evaluates four bio-inspired longitudinal vortex generator (VG) configurations in a high-temperature FTHE with flue-gas inlet temperature ∼1230 K: double-delta, curved double-delta, alula, and a new curved-alula geometry. The reference fin is not hydraulically plain; it already incorporates leading-edge separation columns and convex protrusions, so the alula-type winglets are assessed as downstream add-ons acting on a strongly disturbed flow. In a second step, perforations (one, two and three circular holes) are introduced into the curved-alula VGs to further tailor the flow field. Three-dimensional simulations with the Shear Stress Transpor (SST) <span><math><mrow><mi>k</mi><mo>−</mo><mi>ω</mi></mrow></math></span> model, temperature-dependent flue-gas properties and conjugate conduction are carried out for gas-side Reynolds numbers <span><math><mrow><mi>R</mi><msub><mi>e</mi><mi>g</mi></msub><mo>≈</mo><mn>8.0</mn><mspace></mspace><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>2</mn></msup></mrow></math></span> – <span><math><mrow><mn>3.6</mn><mspace></mspace><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>3</mn></msup></mrow></math></span> (mass flow rates 0.5 – 2.5 g/s), and the designs are compared in terms of surface heat flux, Nusselt number, friction factor and hydrothermal performance factor (HTPF). For this already-promoted fin, the additional downstream winglets provide moderate, incremental hydrothermal gains. At the highest Reynolds number, the best non-perforated design (curved-alula) increases surface heat flux from 1630.9 to 1794.7 kW/m² (∼ 10 % gain) and the Nusselt number from 227.6 to 242.6 (∼ 7 % gain), while the friction factor rises from 0.26 to about 0.30, yielding HTPF values close to unity (∼ 0.9 – 1.0). Introducing circular perforations into the curved-alula winglets acts mainly as a wake-bleeding refinement: the three-hole configuration provides a heat flux of 1824.7 kW/m² and a pressure drop of 127.9 Pa, with HTPF in the range ∼ 1.03 – 1.14 and a small (∼ 1 – 3 %) improvement over the solid curved-alula design. Flow-field analysis shows that the perforated curved-alula VGs shrink tube-wake regions, thin the thermal boundary layer and homogenize the fin-surface temperature (outlet-gas temperature ∼ 510 – 520 K and fin-surface temperature ∼ 420 – 421 K for the three-hole case). An optimal flue-gas mass flow rate of ∼ 1 g/s (<span><math><mrow><mi>R</mi><msub><mi>e</mi><mi>g</mi></msub><mo>≈</mo><mn>1.5</mn><mspace></mspace><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>3</mn></msup></mrow></math></span>) is identified, beyond which additional heat-transfer gains are offset by rapidly increasing pressure losses. Overall, the results highlight that initial fin geometry and VG placement are as import","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128396"},"PeriodicalIF":5.8,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026034","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 : 2026-01-22DOI: 10.1016/j.ijheatmasstransfer.2026.128412
Wei Zhao , Zhangchi Zhao , Yang Xue , Minqi Zhu , Wubing Wan , Hongyan He , Zhen Li , Junhua Zhao , Ning Wei
Tube-fin heat exchangers (TFHEs) often face a fundamental constraint between heat transfer enhancement and flow resistance. This study proposes a bio-inspired airfoil fin configuration to improve the balance between heat transfer and flow resistance, enhancing overall thermal–hydraulic performance. An integrated optimization framework combining three-dimensional computational fluid dynamics (CFD), artificial neural network (ANN) surrogate modeling, and a non-dominated sorting genetic algorithm with elite strategy (NSGA-II) is developed to achieve balanced performance. Five key geometric and operational parameters are selected as optimization variables to capture the coupling between fin geometry and flow behavior. Bayesian-regularized neural networks are trained to predict the Colburn factor (j) and friction factor (f) with high accuracy, yielding coefficients of determination (R²) above 0.99. The NSGA-II algorithm identifies Pareto-optimal configurations that maximize heat transfer while minimizing flow resistance. The optimized bio-inspired tube-fin heat exchanger achieves a 16.39% improvement in overall thermal-hydraulic performance compared with the conventional plain-fin model. This work establishes a data-driven framework for the intelligent design and optimization of TFHEs, offering guidance for next-generation high-efficiency thermal management systems.
{"title":"Intelligent optimization of bio-inspired airfoil fins based on NACA series profiles for enhanced thermal-hydraulic performance in tube-fin heat exchangers","authors":"Wei Zhao , Zhangchi Zhao , Yang Xue , Minqi Zhu , Wubing Wan , Hongyan He , Zhen Li , Junhua Zhao , Ning Wei","doi":"10.1016/j.ijheatmasstransfer.2026.128412","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128412","url":null,"abstract":"<div><div>Tube-fin heat exchangers (TFHEs) often face a fundamental constraint between heat transfer enhancement and flow resistance. This study proposes a bio-inspired airfoil fin configuration to improve the balance between heat transfer and flow resistance, enhancing overall thermal–hydraulic performance. An integrated optimization framework combining three-dimensional computational fluid dynamics (CFD), artificial neural network (ANN) surrogate modeling, and a non-dominated sorting genetic algorithm with elite strategy (NSGA-II) is developed to achieve balanced performance. Five key geometric and operational parameters are selected as optimization variables to capture the coupling between fin geometry and flow behavior. Bayesian-regularized neural networks are trained to predict the Colburn factor (<em>j</em>) and friction factor (<em>f</em>) with high accuracy, yielding coefficients of determination (<em>R²</em>) above 0.99. The NSGA-II algorithm identifies Pareto-optimal configurations that maximize heat transfer while minimizing flow resistance. The optimized bio-inspired tube-fin heat exchanger achieves a 16.39% improvement in overall thermal-hydraulic performance compared with the conventional plain-fin model. This work establishes a data-driven framework for the intelligent design and optimization of TFHEs, offering guidance for next-generation high-efficiency thermal management systems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"259 ","pages":"Article 128412"},"PeriodicalIF":5.8,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035324","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}
During a mission, the thermal state of a spacecraft can change because of factors such as variations in component contact conditions and degradation in the surface optical properties. These uncertainties make it difficult for the pre-launch thermal mathematical model (TMM) to estimate the on-orbit temperature distribution accurately. To address this issue, various methods have been developed over the years to estimate the on-orbit temperature distribution using partial onboard temperature measurements. However, conventional methods struggle to predict the temperature distribution of large-scale spacecraft systems with >1000 nodes. In this study, we proposed a method based on graph neural network (GNN) to incorporate thermal coupling structures into an inference model, enabling efficient estimation of the temperature distributions in large-scale spacecraft systems. The complex thermal structure of the spacecraft was represented as graph data composed of nodes and edges to which GNN was applied. Numerical experiments demonstrated that by learning based on the thermal structure of the spacecraft, the proposed method achieved large-scale temperature prediction with an average error of about 1 K, which was less than half of the computational cost of previous methods. The results indicated that GNN could integrate the structural features inherent in spacecraft thermal phenomena into the learning process, thereby allowing flexible scalability for large systems. Thus, the proposed method represents spacecraft TMMs that integrate physical insights with machine learning.
{"title":"System-wide spacecraft temperature estimation using graph neural networks","authors":"Daichi Yamashita , Hiroto Tanaka , Tsubasa Ikami , Hiroki Nagai","doi":"10.1016/j.ijheatmasstransfer.2026.128398","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128398","url":null,"abstract":"<div><div>During a mission, the thermal state of a spacecraft can change because of factors such as variations in component contact conditions and degradation in the surface optical properties. These uncertainties make it difficult for the pre-launch thermal mathematical model (TMM) to estimate the on-orbit temperature distribution accurately. To address this issue, various methods have been developed over the years to estimate the on-orbit temperature distribution using partial onboard temperature measurements. However, conventional methods struggle to predict the temperature distribution of large-scale spacecraft systems with >1000 nodes. In this study, we proposed a method based on graph neural network (GNN) to incorporate thermal coupling structures into an inference model, enabling efficient estimation of the temperature distributions in large-scale spacecraft systems. The complex thermal structure of the spacecraft was represented as graph data composed of nodes and edges to which GNN was applied. Numerical experiments demonstrated that by learning based on the thermal structure of the spacecraft, the proposed method achieved large-scale temperature prediction with an average error of about 1 K, which was less than half of the computational cost of previous methods. The results indicated that GNN could integrate the structural features inherent in spacecraft thermal phenomena into the learning process, thereby allowing flexible scalability for large systems. Thus, the proposed method represents spacecraft TMMs that integrate physical insights with machine learning.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"259 ","pages":"Article 128398"},"PeriodicalIF":5.8,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035396","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 : 2026-01-22DOI: 10.1016/j.ijheatmasstransfer.2026.128408
Tianyi Zhang, Yulong Yu, Hang Yu, Yifan Wang, Lei Chen, Wen-Quan Tao
To manage the temperature of liquid-cooled lithium-ion batteries under complex operating conditions, an adaptive Long Short-Term Memory–Model Predictive Control (LSTM–MPC) collaborative control framework is proposed. The LSTM network performs multi-horizon short-term prediction of temperature rise based on historical current, voltage, and temperature profiles, while predictive uncertainty is quantified using Monte Carlo (MC) Dropout. An interval score–based weighting scheme is employed to fuse multi-horizon forecasts and provide reliable look-ahead information for the MPC controller, which optimizes coolant flow under thermal safety and pump power constraints. Under the US06 driving cycle, the maximum temperature overrun is reduced from 1.335 °C to 0.352 °C, while the over-temperature duration is shortened from 631 s to 202 s. For composite driving cycles at ambient temperatures of 30 °C, 35 °C, and 40 °C, pump energy consumption is reduced by 52%, 58%, and 37%, respectively, compared with constant-flow control, while maintaining comparable peak temperature. The results demonstrate that the proposed LSTM–MPC framework supports anticipatory pre-cooling and improved energy efficiency under thermal safety constraints, indicating promising potential for practical battery thermal management applications.
{"title":"Intelligent predictive cooling strategy for liquid-cooled lithium-ion batteries under dynamic operating conditions","authors":"Tianyi Zhang, Yulong Yu, Hang Yu, Yifan Wang, Lei Chen, Wen-Quan Tao","doi":"10.1016/j.ijheatmasstransfer.2026.128408","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128408","url":null,"abstract":"<div><div>To manage the temperature of liquid-cooled lithium-ion batteries under complex operating conditions, an adaptive Long Short-Term Memory–Model Predictive Control (LSTM–MPC) collaborative control framework is proposed. The LSTM network performs multi-horizon short-term prediction of temperature rise based on historical current, voltage, and temperature profiles, while predictive uncertainty is quantified using Monte Carlo (MC) Dropout. An interval score–based weighting scheme is employed to fuse multi-horizon forecasts and provide reliable look-ahead information for the MPC controller, which optimizes coolant flow under thermal safety and pump power constraints. Under the US06 driving cycle, the maximum temperature overrun is reduced from 1.335 °C to 0.352 °C, while the over-temperature duration is shortened from 631 s to 202 s. For composite driving cycles at ambient temperatures of 30 °C, 35 °C, and 40 °C, pump energy consumption is reduced by 52%, 58%, and 37%, respectively, compared with constant-flow control, while maintaining comparable peak temperature. The results demonstrate that the proposed LSTM–MPC framework supports anticipatory pre-cooling and improved energy efficiency under thermal safety constraints, indicating promising potential for practical battery thermal management applications.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"259 ","pages":"Article 128408"},"PeriodicalIF":5.8,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035395","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 : 2026-01-21DOI: 10.1016/j.ijheatmasstransfer.2026.128387
Ritian Ji , Zhiguo Qu , Ruiwu Lei , Hui Wang , Jing Meng , Jianfei Zhang , Binbin Jiao
In the field of thermal management for electronic devices, transient conjugate heat transfer (TCHT) poses significant challenges due to alternating heat sources, necessitating cold plate designs that achieve high heat transfer efficiency, low flow resistance, and lightweight construction. Conventional topology optimization (TO) for conjugate heat transfer (CHT) employs discrete adjoint methods optimized for steady-state scenarios, whereas TCHT applications often resort to simplified governing equations to reduce computational burdens, at the expense of accuracy. To address this, we introduce a finite-volume-based Continuous Adjoint-based Transient Topology Optimization for Conjugate Heat Transfer (CATTO-CHT) framework, which derives adjoint equations directly from the continuous Navier-Stokes and energy equations, preserving transient fidelity while enhancing efficiency via semi-analytical sensitivity analysis and checkpointing for time-dependent adjoints. Implemented on the OpenFOAM platform, CATTO-CHT integrates density-based TO with a Darcy porosity model for fluid-solid variation, alongside transient adjoint solvers that minimize time-averaged temperatures under power dissipation constraints. Applied to water-cooled plates under constant, square-wave, and sine-wave heat sources, the method yields vein-like biomimetic flow channels, with parametric analyses revealing how heating duration and oscillation periods influence branching patterns to improve flow distribution and boundary layer disruption. Compared to straight-channel baselines under equivalent mass and pump power constraints, the optimized designs enhance equivalent heat transfer coefficients by factors of 1.78, 1.65, and 1.55 for the respective heat source cases, underscoring CATTO-CHT's potential for advanced, lightweight solutions in dynamic thermal applications.
{"title":"Topology optimization method of cold plates for transient conjugate heat transfer process based on continuous adjoint method","authors":"Ritian Ji , Zhiguo Qu , Ruiwu Lei , Hui Wang , Jing Meng , Jianfei Zhang , Binbin Jiao","doi":"10.1016/j.ijheatmasstransfer.2026.128387","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128387","url":null,"abstract":"<div><div>In the field of thermal management for electronic devices, transient conjugate heat transfer (TCHT) poses significant challenges due to alternating heat sources, necessitating cold plate designs that achieve high heat transfer efficiency, low flow resistance, and lightweight construction. Conventional topology optimization (TO) for conjugate heat transfer (CHT) employs discrete adjoint methods optimized for steady-state scenarios, whereas TCHT applications often resort to simplified governing equations to reduce computational burdens, at the expense of accuracy. To address this, we introduce a finite-volume-based Continuous Adjoint-based Transient Topology Optimization for Conjugate Heat Transfer (CATTO-CHT) framework, which derives adjoint equations directly from the continuous Navier-Stokes and energy equations, preserving transient fidelity while enhancing efficiency via semi-analytical sensitivity analysis and checkpointing for time-dependent adjoints. Implemented on the OpenFOAM platform, CATTO-CHT integrates density-based TO with a Darcy porosity model for fluid-solid variation, alongside transient adjoint solvers that minimize time-averaged temperatures under power dissipation constraints. Applied to water-cooled plates under constant, square-wave, and sine-wave heat sources, the method yields vein-like biomimetic flow channels, with parametric analyses revealing how heating duration and oscillation periods influence branching patterns to improve flow distribution and boundary layer disruption. Compared to straight-channel baselines under equivalent mass and pump power constraints, the optimized designs enhance equivalent heat transfer coefficients by factors of 1.78, 1.65, and 1.55 for the respective heat source cases, underscoring CATTO-CHT's potential for advanced, lightweight solutions in dynamic thermal applications.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"259 ","pages":"Article 128387"},"PeriodicalIF":5.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035323","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 : 2026-01-21DOI: 10.1016/j.ijheatmasstransfer.2026.128411
Jaymeen Patel , Tino S. , Kameswararao Anupindi
Flow boiling in micro- and mini-channels offers an effective approach for cooling electronic devices characterized by high heat dissipation within a constrained footprint. In this study, bubble dynamics and heat transfer characteristics of flow boiling in a non-circular mini-channel, using a single seeded bubble with conjugate heat transfer, are investigated numerically. A three-dimensional copper mini-channel with water as the working fluid is oriented from ° to ° in 45° increments for this study. The effect of parameters such as mass flux, aspect ratio, and hydraulic diameter are also studied. This mini-channel represents an intermediate channel of a multi-channel evaporator. The results indicate that the effect of orientation becomes significant for larger hydraulic diameter mini-channels, influencing both bubble dynamics and heat transfer characteristics, while it remains minimal for aspect ratios not equal to one. Also with increasing mass flux, the variation in bubble transit time diminishes, while the variation in Nusselt number increases across orientations. Wall superheat shows no significant change with orientation and different hydraulic diameters but varies notably with change in aspect ratio and mass flux. The highest Nusselt number consistently occurs at vertically downward (°) orientation except for an aspect ratio of 2 case, where it occurs at ° orientation. Across all parameter variations, the highest Nusselt number occurs for an aspect ratio of 0.5, the lowest bubble transit time for an aspect ratio of 2, and the smallest dry patch area for a mass flux . The variation in orientation, in combination with channel parameters, can help in optimizing multi-channel evaporator design for real-world applications.
{"title":"Numerical study of channel orientation effects on boiling heat transfer associated with single-bubble behavior in rectangular mini-channel","authors":"Jaymeen Patel , Tino S. , Kameswararao Anupindi","doi":"10.1016/j.ijheatmasstransfer.2026.128411","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128411","url":null,"abstract":"<div><div>Flow boiling in micro- and mini-channels offers an effective approach for cooling electronic devices characterized by high heat dissipation within a constrained footprint. In this study, bubble dynamics and heat transfer characteristics of flow boiling in a non-circular mini-channel, using a single seeded bubble with conjugate heat transfer, are investigated numerically. A three-dimensional copper mini-channel with water as the working fluid is oriented from <span><math><mrow><mo>−</mo><mn>90</mn></mrow></math></span>° to <span><math><mrow><mo>+</mo><mn>90</mn></mrow></math></span>° in 45° increments for this study. The effect of parameters such as mass flux, aspect ratio, and hydraulic diameter are also studied. This mini-channel represents an intermediate channel of a multi-channel evaporator. The results indicate that the effect of orientation becomes significant for larger hydraulic diameter mini-channels, influencing both bubble dynamics and heat transfer characteristics, while it remains minimal for aspect ratios not equal to one. Also with increasing mass flux, the variation in bubble transit time diminishes, while the variation in Nusselt number increases across orientations. Wall superheat shows no significant change with orientation and different hydraulic diameters but varies notably with change in aspect ratio and mass flux. The highest Nusselt number consistently occurs at vertically downward (<span><math><mrow><mo>−</mo><mn>90</mn></mrow></math></span>°) orientation except for an aspect ratio of 2 case, where it occurs at <span><math><mrow><mo>−</mo><mn>45</mn></mrow></math></span>° orientation. Across all parameter variations, the highest Nusselt number occurs for an aspect ratio of 0.5, the lowest bubble transit time for an aspect ratio of 2, and the smallest dry patch area for a mass flux <span><math><mrow><mn>400</mn><mspace></mspace><mi>kg</mi><mo>/</mo><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>s</mi></mrow></math></span>. The variation in orientation, in combination with channel parameters, can help in optimizing multi-channel evaporator design for real-world applications.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"259 ","pages":"Article 128411"},"PeriodicalIF":5.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035394","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 : 2026-01-21DOI: 10.1016/j.ijheatmasstransfer.2026.128351
Md Rakibul Hasan Roni , Mohammad Jalal Inanlu , Simran Singh , Md Rakib Hossain , Vishwanath Ganesan , Mohamed H Mousa , Cheng-Min Yang , Trevor G. Aguirre , Mina M.K. Mikhaeel , Kashif Nawaz , Nenad Miljkovic
Flow boiling is essential in moving heat in refrigeration and air conditioning systems, nuclear reactors, and chemical manufacturing plants due to its efficient utilization of the latent heat of liquid to vapor phase change during vaporization. However, the flow boiling heat transfer performance of conventional bare metallic surfaces can be limited by the low number of active nucleation sites, which are a function of the surface roughness among other factors. Wet chemical etching is a cost-effective, scalable, surface structure fabrication technique that has been shown to significantly influence boiling heat transfer performance. In this study, two distinct copper etching recipes are developed specifically for flow boiling performance enhancement of water. The heat transfer coefficient and pressure drop of the two etch recipes are experimentally investigated in 0.25″ round copper tubes and compared with a reference bare tube of the same size. Experiments are carried out at atmospheric pressure using deionized water as a working fluid over a range of heat fluxes (10 kW/m2 < < 70 kW/m2), mass fluxes (140 kg/(m2·s) < < 255 kg/(m2·s)), and vapor qualities (0 < < 0.11). The results demonstrate that both etching recipes achieve heat transfer coefficient improvements over the plain tube, with the rougher surface providing the highest enhancement (up to 36%). The enhanced thermal performance of the etched tubes is attributed to the increased active nucleation site density and improved surface wetting characteristics. Despite the heat transfer coefficient enhancement, the pressure drop of the etched tubes is found to be similar to that of the bare tube. By carefully selecting the etching parameters, it is possible to fabricate a wide range of cavity sizes for boiling heat transfer enhancement optimized for any working fluid. This work provides insights into how chemical etching can be utilized as an effective technique to impact passive heat transfer enhancements for flow boiling applications.
流动沸腾在制冷和空调系统、核反应堆和化学制造工厂的热量转移中是必不可少的，因为它有效地利用了蒸发过程中液体到蒸汽相变的潜热。然而，传统裸金属表面的流动沸腾传热性能可能受到活性成核位数量少的限制，这是表面粗糙度和其他因素的函数。湿化学蚀刻是一种具有成本效益，可扩展的表面结构制造技术，已被证明对沸腾传热性能有显著影响。在本研究中，开发了两种不同的铜蚀刻配方，专门用于提高水的流动沸腾性能。在0.25″圆铜管中实验研究了两种蚀刻方法的传热系数和压降，并与相同尺寸的参考裸铜管进行了比较。实验在大气压下进行，使用去离子水作为工作流体，热通量（10 kW/m2 < q < 70 kW/m2），质量通量(140 kg/（m2·s) < G < 255 kg/(m2·s)）和蒸汽质量（0 < x < 0.11）。结果表明，两种蚀刻方法都能提高普通管的传热系数，其中粗糙表面的传热系数提高最高（高达36%）。蚀刻管的热性能增强是由于活性成核位点密度的增加和表面润湿特性的改善。尽管换热系数增大，但蚀刻管的压降与裸管的压降相似。通过仔细选择蚀刻参数，可以制造广泛的腔尺寸，以优化任何工作流体的沸腾传热增强。这项工作为如何利用化学蚀刻作为一种有效的技术来影响流动沸腾应用的被动传热增强提供了见解。
{"title":"Scalably-manufactured etched surface structures for enhanced flow boiling heat transfer of water","authors":"Md Rakibul Hasan Roni , Mohammad Jalal Inanlu , Simran Singh , Md Rakib Hossain , Vishwanath Ganesan , Mohamed H Mousa , Cheng-Min Yang , Trevor G. Aguirre , Mina M.K. Mikhaeel , Kashif Nawaz , Nenad Miljkovic","doi":"10.1016/j.ijheatmasstransfer.2026.128351","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128351","url":null,"abstract":"<div><div>Flow boiling is essential in moving heat in refrigeration and air conditioning systems, nuclear reactors, and chemical manufacturing plants due to its efficient utilization of the latent heat of liquid to vapor phase change during vaporization. However, the flow boiling heat transfer performance of conventional bare metallic surfaces can be limited by the low number of active nucleation sites, which are a function of the surface roughness among other factors. Wet chemical etching is a cost-effective, scalable, surface structure fabrication technique that has been shown to significantly influence boiling heat transfer performance. In this study, two distinct copper etching recipes are developed specifically for flow boiling performance enhancement of water. The heat transfer coefficient and pressure drop of the two etch recipes are experimentally investigated in 0.25″ round copper tubes and compared with a reference bare tube of the same size. Experiments are carried out at atmospheric pressure using deionized water as a working fluid over a range of heat fluxes (10 kW/m<sup>2</sup> < <span><math><mi>q</mi></math></span> < 70 kW/m<sup>2</sup>), mass fluxes (140 kg/(m<sup>2</sup>·s) < <span><math><mi>G</mi></math></span> < 255 kg/(m<sup>2</sup>·s)), and vapor qualities (0 < <span><math><mi>x</mi></math></span> < 0.11). The results demonstrate that both etching recipes achieve heat transfer coefficient improvements over the plain tube, with the rougher surface providing the highest enhancement (up to 36%). The enhanced thermal performance of the etched tubes is attributed to the increased active nucleation site density and improved surface wetting characteristics. Despite the heat transfer coefficient enhancement, the pressure drop of the etched tubes is found to be similar to that of the bare tube. By carefully selecting the etching parameters, it is possible to fabricate a wide range of cavity sizes for boiling heat transfer enhancement optimized for any working fluid. This work provides insights into how chemical etching can be utilized as an effective technique to impact passive heat transfer enhancements for flow boiling applications.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"259 ","pages":"Article 128351"},"PeriodicalIF":5.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035392","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 : 2026-01-21DOI: 10.1016/j.ijheatmasstransfer.2026.128347
Jean Lachaud
<div><div>This review synthesizes recent advancements in pyrolysis modeling and simulation, grounded in a historical overview of pyrolysis science and technologies. The field originated with the pioneering work of Bamford, Crank, and Malan (1946), who introduced a macroscopic heat conduction model that incorporated the endothermic nature of pyrolysis. Since then, pyrolysis modeling has evolved into a multifaceted field, with diverse approaches emerging across disciplines, particularly driven by applications in aerospace thermal protection systems, fire safety, and biomass conversion. To unify these approaches, we propose a comprehensive and generic modeling framework, starting from rigorous pore-scale conservation equations that are volume-averaged to derive macroscopic models. This framework clarifies underlying assumptions and reveals that existing models are subsets of this more general formulation. The same methodology is applied to the closure models used in the different communities for the chemical and physical parameters, such as pyrolysis mechanisms, heat and mass transport properties, and mechanical moduli. The large variety of boundary conditions found in the literature is summarized and classified into six categories, ranging from fully coupled methods to simplified boundary layer approaches.</div><div>Using a detailed, term-by-term checklist, we compare the models implemented in 54 simulation tools, selected for their original scientific contributions and/or widespread adoption within their primary application domains. Information is also provided on their numerical frameworks, original developers, ownership, and recent updates, offering a practical and comprehensive overview of the current modeling landscape. Across disciplines, numerical methods and code dimensionality tend to exhibit uniformity within a given time period, initially relying on unidimensional proprietary finite-difference codes and currently progressing towards advanced three-dimensional numerical frameworks. Regarding the mathematical models implemented, a historical consensus on a certain number of assumptions within each community has persisted until very recently. However, research in progress is now converging towards comprehensive multi-physics models that incorporate mass, momentum, and energy conservation while accounting for major physical phenomena, with the goal of progressively overcoming current scientific challenges.</div><div>Six modeling and simulation challenges are shared by the different communities : (1) conducting systematic studies to quantify uncertainties from mathematical model assumptions and updating the models as needed, (2) integrating pyrolysis into the classical chemistry theory, (3) consolidating a common database to develop secondary reaction mechanisms, (4) developing the solid mechanics of pyrolyzing materials, (5) measuring evolving material properties, and (6) establishing generic benchmarks to foster interactions and collaborati
本文在对热解科学和技术的历史回顾的基础上，综合了热解建模和模拟的最新进展。该领域起源于Bamford， Crank, and Malan（1946）的开创性工作，他们引入了包含热解吸热性质的宏观热传导模型。从那时起，热解建模已经发展成为一个多方面的领域，跨学科的不同方法层出不穷，特别是在航空航天热防护系统、消防安全和生物质转化方面的应用。为了统一这些方法，我们提出了一个全面和通用的建模框架，从严格的体积平均孔隙尺度守恒方程开始推导宏观模型。这个框架澄清了潜在的假设，并揭示了现有的模型是这个更一般的公式的子集。将相同的方法应用于不同群落中使用的化学和物理参数的闭合模型，如热解机制、热量和质量传递性质以及机械模量。总结了文献中发现的各种各样的边界条件，并将其分为六类，从完全耦合方法到简化边界层方法。使用详细的逐期检查表，我们比较了54种仿真工具中实现的模型，这些模型是根据其原始科学贡献和/或在其主要应用领域内的广泛采用而选择的。还提供了有关其数值框架，原始开发人员，所有权和最近更新的信息，提供了当前建模景观的实用和全面概述。跨学科，数值方法和代码维度倾向于在给定时间段内表现出一致性，最初依赖于一维专有有限差分代码，目前正在向先进的三维数值框架发展。关于所实施的数学模型，每个社区内对一定数量的假设的历史共识一直持续到最近。然而，目前正在进行的研究正在朝着综合多物理场模型的方向发展，这些模型将质量、动量和能量守恒结合起来，同时考虑到主要的物理现象，目标是逐步克服当前的科学挑战。六个建模和仿真挑战是由不同的社区共享：(1)进行系统研究，量化数学模型假设的不确定性，并根据需要更新模型；(2)将热解纳入经典化学理论；(3)巩固公共数据库以开发二次反应机制；(4)发展热解材料的固体力学；(5)测量不断变化的材料性质；(6)建立通用基准以促进相互作用和协作。
{"title":"Pyrolysis models and simulation tools: A cross-community comparative review highlighting open challenges","authors":"Jean Lachaud","doi":"10.1016/j.ijheatmasstransfer.2026.128347","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128347","url":null,"abstract":"<div><div>This review synthesizes recent advancements in pyrolysis modeling and simulation, grounded in a historical overview of pyrolysis science and technologies. The field originated with the pioneering work of Bamford, Crank, and Malan (1946), who introduced a macroscopic heat conduction model that incorporated the endothermic nature of pyrolysis. Since then, pyrolysis modeling has evolved into a multifaceted field, with diverse approaches emerging across disciplines, particularly driven by applications in aerospace thermal protection systems, fire safety, and biomass conversion. To unify these approaches, we propose a comprehensive and generic modeling framework, starting from rigorous pore-scale conservation equations that are volume-averaged to derive macroscopic models. This framework clarifies underlying assumptions and reveals that existing models are subsets of this more general formulation. The same methodology is applied to the closure models used in the different communities for the chemical and physical parameters, such as pyrolysis mechanisms, heat and mass transport properties, and mechanical moduli. The large variety of boundary conditions found in the literature is summarized and classified into six categories, ranging from fully coupled methods to simplified boundary layer approaches.</div><div>Using a detailed, term-by-term checklist, we compare the models implemented in 54 simulation tools, selected for their original scientific contributions and/or widespread adoption within their primary application domains. Information is also provided on their numerical frameworks, original developers, ownership, and recent updates, offering a practical and comprehensive overview of the current modeling landscape. Across disciplines, numerical methods and code dimensionality tend to exhibit uniformity within a given time period, initially relying on unidimensional proprietary finite-difference codes and currently progressing towards advanced three-dimensional numerical frameworks. Regarding the mathematical models implemented, a historical consensus on a certain number of assumptions within each community has persisted until very recently. However, research in progress is now converging towards comprehensive multi-physics models that incorporate mass, momentum, and energy conservation while accounting for major physical phenomena, with the goal of progressively overcoming current scientific challenges.</div><div>Six modeling and simulation challenges are shared by the different communities : (1) conducting systematic studies to quantify uncertainties from mathematical model assumptions and updating the models as needed, (2) integrating pyrolysis into the classical chemistry theory, (3) consolidating a common database to develop secondary reaction mechanisms, (4) developing the solid mechanics of pyrolyzing materials, (5) measuring evolving material properties, and (6) establishing generic benchmarks to foster interactions and collaborati","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"259 ","pages":"Article 128347"},"PeriodicalIF":5.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035326","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}
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