International Journal of Heat and Mass Transfer最新文献

{"title":"Multi-goal forced convection heat transfer control for cylinder under online and offline scenarios via deep reinforcement learning","authors":"Feitong Wang ,&nbsp;Yumeng Tang ,&nbsp;Jiexuan Hou ,&nbsp;Yangwei Liu","doi":"10.1016/j.ijheatmasstransfer.2026.128468","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128468","url":null,"abstract":"<div><div>Deep reinforcement learning (DRL)-based forced convection heat transfer control encounters challenges when facing complex control objectives and scenarios. This study focuses on a two-dimensional cylindrical heat source within a narrow cavity. First, DRL is applied to perform the energy-efficient cooling task with an energy penalty term incorporated into the reward. Results show that the continuous DRL algorithm achieves the best performance, with a comprehensive gain exceeding the baseline by 25.1%. To handle temperature control tasks with variable goals, a goal-oriented reinforcement learning (GoRL) framework is established. Results show that control accuracy decreases as the goal space expands, however, it can be improved by employing hindsight experience replay with a future method and designing the observation space such that the reward becomes a function of the observation. The GoRL framework achieves precise variable-goal temperature control across a broad continuous goal space of 20 K with a single training process, yielding a temperature variance of 0.1071 while consuming only 5% computational resources required by traditional DRL frameworks. Furthermore, considering scenarios where online DRL learning and interaction are restricted due to safety or cost constraints, a continuous goal-oriented conservative <em>Q</em>-learning (GoCQL) framework is proposed, aiming to rapidly accomplish variable-goal temperature control solely based on the randomized offline dataset. Results demonstrate that GoCQL agent exhibits excellent generalization ability, achieving a temperature variance of 0.1572. Moreover, the time consumption of offline learning is less than 1% of that of online learning under a complete training session, enabling fast acquisition of control strategies in scenarios where online interaction is impractical.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128468"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A high-precision analytical model of transient thermal stresses of through-silicon vias in 3-D integrated circuits","authors":"Luhao Zhai,&nbsp;Junqin Zhang,&nbsp;Guangbao Shan,&nbsp;Xin Jin,&nbsp;Wenting Chen,&nbsp;Yintang Yang","doi":"10.1016/j.ijheatmasstransfer.2026.128356","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128356","url":null,"abstract":"<div><div>In three-dimensional integrated circuits (3-D ICs), through-silicon vias (TSVs) are subject to significant thermal stress due to mismatches in the coefficients of thermal expansion (CTE) among constituent materials, which severely compromises device reliability. Grounded in thermoelastic theory, this paper presents a high-precision analytical model for predicting transient thermal stress in TSVs. First, an analytical solution for the transient temperature field within TSVs is derived using heat conduction theory in a cylindrical coordinate system. Subsequently, by incorporating the thermoelastic displacement potential and Love's displacement function, a closed-form analytical model for transient thermal stress is formulated. The model further accounts for axial third-kind thermal boundary conditions and incorporates temperature-dependent material properties to enhance physical realism. Validation against COMSOL multiphysics simulations demonstrates that the maximum relative error and maximum absolute error in the predicted transient temperature field remain below 1.2 % and 0.4 K, respectively, while the corresponding errors for von Mises stress are within 1.6 % and 0.8 MPa. Notably, the computational efficiency of the proposed model exceeds that of the finite element method (FEM) by approximately two orders of magnitude. Moreover, it exhibits strong adaptability across a wide range of material combinations and geometric configurations. We further employ the analytical model to investigate the effect of thermal stress on carrier mobility in TSVs and the stress interaction between adjacent TSVs. In comparison with classical 2-D Lamé solutions and 3-D Kane-Mindlin theory, the proposed model achieves superior accuracy without relying on empirical correction factors and effectively captures the spatial distribution of thermal stress in TSVs under transient thermal conditions. This study confirms that the developed analytical model offers exceptional accuracy and efficiency in characterizing transient thermal stress distributions in 3-D IC TSVs, thereby providing a robust and precise tool for thermomechanical reliability assessment and design optimization.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128356"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and fabrication of high-permeability plain-woven ceramic matrix composites: Experimental and numerical investigation on flow and heat transfer characteristics","authors":"Tao Ding ,&nbsp;Shiyu Qian ,&nbsp;Hua Zhou ,&nbsp;Hainan Zhang ,&nbsp;Xiaoxuan Chen ,&nbsp;Weigang Ma","doi":"10.1016/j.ijheatmasstransfer.2026.128399","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128399","url":null,"abstract":"<div><div>Ceramic matrix composites (CMCs), distinguished by their high-temperature resistance, low density, and high specific strength, are extensively employed in the hot-end components of aero-engines. The pores inside CMCs can serve as seepage channels for transpiration cooling. This study obtained the permeability and inertial coefficient of two-dimensional plain-woven (2DPW) CMCs by experiments and then established a parametric modeling method and pore-scale simulation methodology specifically for 2DPW, and the internal flow mechanism was analyzed. Firstly, an experimental investigation was conducted to explore the flow characteristics, and the permeability and inertial coefficients among different porous medium were compared. Second, the internal geometric structure of the material was captured using a micro-computed tomography scanning method, and a simplified parametric modeling method was developed. Third, a representative volume element was constructed for pore-scale internal flow simulations. Numerically predicted pressure drops versus flow rate characteristics were validated against experimental data. Finally, an analysis was conducted on the internal flow and heat transfer characteristics, and the flow resistance as well as the volumetric convective heat transfer coefficient were acquired. The results indicated that the complex pore structure induced by inter-layer misalignment gives rise to high fluid tortuosity, resulting in significant variations in the magnitude and direction of the flow velocity, which contribute to the high inertial resistance. For the coupled flow and heat transfer process, the numerical simulation results show that the staggered 2D plain woven structure forces the fluid to pass through the inter-layer pores when flowing through the woven meshes of different layers, which generates substantial flow resistance while enhancing the heat transfer performance. The high-velocity flow within the narrow inter-layer pores provides the basis for high heat transfer, and the dual heat sources are derived from both the high-temperature solid matrix and the high-temperature swirling flow in the inter-bundle pores. This study provided guidance for the establishment of 2DPW geometric models, the analysis of flow and heat transfer characteristics, and the gradient porosity design in transpiration cooling.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128399"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic enhancement of cryogenic quenching using porous low-thermal-conductivity coatings","authors":"Chunkai Guo,&nbsp;Peng Zhang","doi":"10.1016/j.ijheatmasstransfer.2026.128393","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128393","url":null,"abstract":"<div><div>Applying a porous low-thermal-conductivity coating layer on the surface is an effective method to enhance cryogenic quenching process. However, existing studies have not thoroughly explored the mechanisms of quenching enhancement by the porous structures, nor have they systematically optimized the structural parameters of porous coating for cryogenic quenching process. Therefore, in this study, an effective method of cryogenic quenching enhancement employing a porous low-thermal-conductivity coating is proposed. The pool quenching experiments are carried out using a pristine rodlet, eight rodlets coated with pure Teflon layers of varying thicknesses, and fifteen rodlets coated with porous Teflon layers of different thicknesses and porosities. It is found that the chilldown time of the rodlets with porous Teflon coating layer is reduced by approximately 56.3 %–82.8 % relative to the bare rodlet. By comparing the boiling curves of the rodlets with pure Teflon coating layers and porous Teflon coating layers, the mechanism of synergistic enhancement of cryogenic quenching by porous low-thermal-conductivity coatings is revealed. Furthermore, it can be found that the porous Teflon coating layer with a porosity greater than 45 % exhibits a higher heat flux across the entire cryogenic quenching process compared with the pure Teflon coating layer under the condition of similar thermal resistance. This work paves a new design strategy to enhance cryogenic quenching performance across the entire regime of quenching process.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128393"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146015849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unidirectional flow and heat transfer optimization of pin-fin cold plates for power battery thermal management: Integrated experimental, simulation and multi-objective optimization study","authors":"Shuai Feng ,&nbsp;Xingyan Dong ,&nbsp;Ziqiang He ,&nbsp;Chenguang Lai ,&nbsp;Jie Song ,&nbsp;Lijuan Fu ,&nbsp;Ranran Fang ,&nbsp;Weiping Li ,&nbsp;Zhanxiao Kang","doi":"10.1016/j.ijheatmasstransfer.2026.128482","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128482","url":null,"abstract":"<div><div>To address the thermal management challenges of high-power battery packs, a novel hybrid cold plate integrating straight channels and pin fins is proposed in this study. The structural and operational parameters of the cold plate are systematically optimized through a combined approach incorporating multi-objective optimization, numerical simulations, and experimental validation. Results indicate that the circular pin-fin (C-Pin-fin) configuration achieves the optimal thermo-hydraulic performance. At a mass flow rate of 0.03 kg/s, compared with conventional straight-channel designs, the maximum temperature is reduced by 2.9 K and the temperature difference is decreased by 0.7 K. Sensitivity analysis shows that channel height is the dominant factor affecting pressure drop (with a sensitivity of 44.2%), while mass flow rate primarily influences temperature uniformity (with a sensitivity of 53 %). Compared to the baseline model, the optimized design improves temperature uniformity by 23.1 %, reduces pressure drop by 43.2 %, achieves a maximum reduction in thermal resistance of 16 %, and attains a maximum cooling efficiency factor of 15,452. Furthermore, a channel height of 1.5 mm is identified as optimal for balancing performance and structural compactness. The superior performance of the proposed design is experimentally validated, demonstrating its potential for application in advanced battery thermal management systems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128482"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal-hydraulic performance assessment of a micro shell-and-tube heat exchanger operating under part-load conditions in the NET Power cycle recuperator","authors":"Iván Velázquez ,&nbsp;Frederiek Demeyer ,&nbsp;Miriam Reyes","doi":"10.1016/j.ijheatmasstransfer.2026.128419","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128419","url":null,"abstract":"<div><div>This paper numerically investigates the thermal-hydraulic performance of a micro shell-and-tube heat exchanger (MSTHE) for application in the thermal recuperator of the innovative oxy-combustion-based NET Power cycle, operating under cycle-relevant part-load conditions. The aim is to support the technological transition from the established printed circuit heat exchangers (PCHE) to MSTHE, which offer a lower inertia, cost-effective, and maintenance-friendly high-performance alternative. To this end, a thermal-hydraulic computational model of the MSTHE was developed, capable of capturing the rapid variation of the supercritical CO₂ (scCO₂) properties and the partial filmwise condensation of the turbine exhaust gases. Results show that the MSTHE must contain at least 60,000 tubes so that the pressure drop on the tube-side is lower than 1 bar at nominal conditions. The MSTHE effectiveness decreases from 89.2% to 65.1% as the cycle load is reduced from 100% to 20%. The overall heat transfer coefficient decreases gradually between 100% and 40% cycle load, drops sharply between 40% and 30%, and then stabilizes between 30% and 20% cycle load. This stabilization is attributed to the abrupt local increase of the heat capacity on the scCO₂-side during the pseudo-critical phase transition, which also enhances local condensation heat release and thickens the condensate film on the shell-side. However, it was found that this phenomenon induces strong axial temperature gradients that may induce thermal stresses, representing a trade-off to the proposed compact design. While the floating microtube bundle of MSTHEs can accommodate these thermal stresses, the rigid compact block structure of PCHE is more prone to damage, revealing an additional key advantage of MSTHEs.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128419"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of mixed convection in a horizontal tube for a liquid metal flow","authors":"Linda Elmlinger,&nbsp;Tim Laube,&nbsp;Benjamin Dietrich,&nbsp;Thomas Wetzel","doi":"10.1016/j.ijheatmasstransfer.2026.128495","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128495","url":null,"abstract":"<div><div>An experimental study of the heat transfer on mixed convection in a turbulent liquid metal flow with azimuthally inhomogeneous heat flux distribution is presented. A horizontal nickel tube is heated in different sections to investigate the influence of heat flux orientation relative to gravity on heat transfer in a liquid metal flow. Four semi-circumferential heat flux distributions (top, bottom, right and bottom right half) are examined. These configurations emulate the azimuthally inhomogeneous heat flux profile that is characteristic of receiver tubes in concentrated solar power plants. The working fluid is a near eutectic alloy of gallium, indium, and tin (GaInSn, <span><math><mrow><mi>P</mi><mi>r</mi><mo>=</mo><mspace></mspace><mn>0.03</mn></mrow></math></span>, <span><math><mrow><msub><mi>ϑ</mi><mtext>melt</mtext></msub><mo>=</mo><msup><mn>11</mn><mo>∘</mo></msup><mi>C</mi></mrow></math></span>). The Péclet number is varied within a range of <span><math><mrow><mn>2.4</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>2</mn></msup><mo>&lt;</mo><mi>P</mi><mi>e</mi><mo>&lt;</mo><mn>3</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>3</mn></msup></mrow></math></span>, while the Rayleigh number is <span><math><mrow><mn>1.6</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>3</mn></msup><mo>&lt;</mo><mi>R</mi><msub><mi>a</mi><mi>q</mi></msub><mo>&lt;</mo><mn>8.2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>3</mn></msup></mrow></math></span>. For all four heat flux distributions, the correlation for the azimuthally averaged Nusselt number <span><math><mrow><mo>〈</mo><mrow><mi>N</mi><mi>u</mi></mrow><mo>〉</mo></mrow></math></span> can be confirmed. The temperature difference along the circumference of the tube reveals mixed convection for heating directions opposing the direction of gravitational acceleration for <span><math><mrow><mi>P</mi><mi>e</mi><mo>&lt;</mo><mn>7.2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mn>2</mn></msup></mrow></math></span>. Based on this quotient, the applicability of the Rayleigh number, the Buhr parameter, the Buoyancy parameter, and the Richardson number as criteria for the determination of mixed convection in liquid metals is discussed. New correlations for the critical Rayleigh number and limits for the Buhr parameter are established.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128495"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of flow and mass transfer dynamics in spacer-filled channels of membrane processes using direct numerical simulations","authors":"Santiago Cespedes,&nbsp;Bastiaan Blankert,&nbsp;Cristian Picioreanu","doi":"10.1016/j.ijheatmasstransfer.2026.128512","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128512","url":null,"abstract":"<div><div>This study evaluates the effect of different flow regimes on the local and global mass transfer coefficient for feed spacer-filled channels in membrane separation processes using Direct Numerical Simulation (DNS). The computational domain was built with arrangements of multiple spacer units based on accurate three-dimensional CT scan of a commercial reverse osmosis feed-spacer. Hydrodynamics was coupled with solute transport and a permeable membrane. Computations were performed in two membrane/spacer configurations: (i) spacer “floating” within the feed channel and (ii) spacer “touching” the membrane, both in a wide range of inlet channel velocities (2 – 60 cm/s). The observed flow-regime was categorized based on dynamics (steady vs. periodic vs. unsteady), subdividing the laminar steady regime based on spatial distribution (regular vs irregular), resulting in four observed regimes: regular laminar-steady, irregular laminar-steady, periodic and unstable, depending on velocity and position. Transition from laminar-steady to unsteady flow occurred for <em>Re</em> &gt; 950 (“floating”) and 720 (“touching”). When more than four spacer cells are considered, different flow-regimes can occur simultaneously at different locations in the channel. Instabilities within the flow arising from external perturbation can trigger unstable flow only at high velocities (40 cm/s), indicating that at industrial conditions (velocity &lt; 16 cm/s) it would be difficult to perturb the flow in a meaningful way. Vortex analysis showed how the spacer works as a static mixer, promoting the splitting and rotation of flow. Furthermore, in the unsteady flow, the presence of vortices traveling within the feed channel assists the transport of solute from the membrane to the bulk, renewing the polarization layer. Finally, the effect of each flow regime on the mass transfer coefficient was shown in the traditional <em>Sh</em>-<em>Re</em> power law (<span><math><mrow><mi>S</mi><mi>h</mi><mo>=</mo><mi>a</mi><mspace></mspace><mi>R</mi><msup><mrow><mi>e</mi></mrow><mi>b</mi></msup><mi>S</mi><msup><mrow><mi>c</mi></mrow><mi>c</mi></msup></mrow></math></span>), where the exponent <em>b</em> varied from the expected 1/3 in the laminar-steady flow to ca. 0.9 in the transitional regime.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128512"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interaction between soil freezing-thawing process and heat extraction by ground heat exchangers: modeling of thermal-hydrological-mechanical coupling in unsaturated soil","authors":"Fuqiang Xu ,&nbsp;Yu Shi ,&nbsp;Can Ji ,&nbsp;Qiang Wang ,&nbsp;Fenghua Duan ,&nbsp;Cong Wang","doi":"10.1016/j.ijheatmasstransfer.2026.128499","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128499","url":null,"abstract":"<div><div>The ground heat exchanger (GHE) is a cost-effective and efficient technology for utilizing shallow geothermal resources, which provides both cooling in summer and heating in winter. In many regions, soil undergoes seasonal freezing in winter. The operation of heat exchangers affects the soil freezing-thawing process, while the ice-water phase transition conversely impacts the performance of the heat exchangers. To explore these interactions, a thermal-hydrological-mechanical (T-H-M) coupling model is developed at the experimental scale, considering the freezing-thawing dynamics in unsaturated soil and the heat exchange between GHEs and the surrounding formation. The results indicate that the ice-water phase transition can delay changes in soil temperature. Heat extraction by GHEs not only forms a frozen zone in their vicinity but also accelerates the freezing process and inhibits the thawing of the overlying frozen soil layer. Moreover, the ice-water phase transition increases the outlet temperature of GHEs during the freezing process and decreases it during the thawing process. Specifically, under lower temperature gradients, the displacement induced by the soil freezing-thawing process is significantly larger than that caused by other factors. And heat extraction exerts a notable effect: a displacement difference of up to 0.58 mm is observed at the upper boundary after 168 h when comparing scenarios with and without heat extraction. Furthermore, the periodic operation of the system expands both the low-temperature zone and the frozen zone. Notably, the ice-water phase transition affects reservoir properties such as relative saturation, thermal conductivity, volumetric heat capacity, and diffusion coefficient, which in turn influence subsequent phase transitions and heat exchange processes. This study provides insights for improving heat exchange efficiency and mitigating soil freezing-thawing risks.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128499"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The synergistic influence of PA-based composite phase change materials and heat exchange structures on heat storage performance","authors":"Yize Liu ,&nbsp;Xin Liu ,&nbsp;Guiju Xing ,&nbsp;Zhaoyi Huo ,&nbsp;Lili Niu ,&nbsp;Haobo Zhang ,&nbsp;Yicheng Liu","doi":"10.1016/j.ijheatmasstransfer.2026.128421","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128421","url":null,"abstract":"<div><div>Low thermal conductivity is widely acknowledged as a major limitation of phase change materials (PCMs), as it markedly affects phase-change heat transfer and system-level performance and thereby restricts practical deployment. Most previous studies have treated fin enhancement and conductive additives separately, whereas a quantitative and systematic analysis of the coupled synergistic mechanism between staggered fins and high loadings of expanded graphite (EG) is still lacking. In this work, experiments combined with validated three-dimensional numerical simulations were conducted under the same test unit and identical boundary conditions to examine 16 cases formed by four heat-transfer structures and four PA-based composite PCMs with EG additions of 0–6 wt%. The results show that EG builds a conductive network, increasing the thermal conductivity to 2.103 W·m⁻¹·K⁻¹ at 6 wt% EG (7.86 times that of PA), but reducing the total stored heat by 10.3%–10.4%. Fin addition accelerates heat transfer: parallel or staggered fins reduce the time for the geometric center of the storage unit to reach 50°C from 27 min to 13 min (a 52% reduction). A pronounced synergy is observed when the composite PCM is coupled with the fin structure. The staggered-fin case with 6 wt% EG yields a synergy index of S = 1.57, further shortening the time to reach 50°C to 2.3 min (a 91.5% reduction), while increasing the average charging power by 323.3% relative to Case 1. These results quantitatively demonstrate the synergistic enhancement provided by staggered fins combined with high EG loading, showing that charging power and thermal response capacity can be substantially improved at the cost of only a modest decrease in stored energy and providing guidance for the design of high-performance phase-change heat exchangers.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"260 ","pages":"Article 128421"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075859","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}