International Journal of Heat and Mass Transfer最新文献

{"title":"Effect of rotation control on thermal performance of phase change unit with annular fins","authors":"Bo Yang ,&nbsp;Junfei Guo ,&nbsp;Muzhi Li ,&nbsp;Wenjing Zhang ,&nbsp;Xiaohu Yang ,&nbsp;Bengt Sundén","doi":"10.1016/j.ijheatmasstransfer.2026.128337","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128337","url":null,"abstract":"<div><div>Thermal energy storage(TES) devices are critical for efficient energy utilization and stable supply in building-integrated solar energy systems. Previous studies on rotation-driven TES devices have overlooked the trade-off between energy consumption and heat storage performance. Numerical simulations were conducted in this study to systematically explore finned paraffin-based thermal energy storage devices. Key thermal performance parameters, including thermal charging behavior, temperature distribution, flow field characteristics, heat storage capacity, heat storage efficiency, and energy consumption, were analyzed to evaluate the impact of rotation on/off switching moments. Results indicate that rotation-driven enhancement significantly shortens the charging time of vertical finned thermal energy storage tubes, with the benefits of this enhancement most pronounced in the late melting stage. The \"first fixed then rotated\" strategy (activating rotation at a liquid fraction of approximately 0.6) outperforms continuous rotation: compared with continuously rotating vertical finned thermal storage tubes, this strategy increases the benefits of reduced melting time, improved melting rate, and enhanced temperature response by 40.47%, 43.52%, and 36.98% per unit energy consumption, respectively. This study fills the existing research gap in dynamic rotation control for finned PCM storage devices. It provides a theoretical basis and technical support for optimizing finned thermal energy storage units in building solar systems, thereby promoting higher energy efficiency and operational stability of such systems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"259 ","pages":"Article 128337"},"PeriodicalIF":5.8,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145903982","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 performance enhancement of blade battery packs via multi-branch-converging channel design","authors":"Xiaoqing Yang ,&nbsp;Xin Zhong ,&nbsp;Chuyan Su ,&nbsp;Kai Chen ,&nbsp;Jiekai Xie","doi":"10.1016/j.ijheatmasstransfer.2026.128330","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128330","url":null,"abstract":"<div><div>Blade batteries have occupied a considerable share in the field of electric vehicles, because they possess a larger heat dissipation area and serve as structural components for power battery packs. However, their liquid cooling (LC) systems still face challenges of non-uniform heat dissipation and large energy loss along the narrow, elongated and tortuous flow channels. This work rationally designs a LC plate (LCP) with multi-branch-converging channels to solve the heat accumulation in the central area of the battery packs. The coolant is split at the inlet area to intentionally moderate local heat transfer and alleviate edge overcooling, whereas in the central area, the converging structure enhances turbulence intensity while extending the coolant residence time to enhance heat transfer. Through a series of optimizations, when the number of diversion channels, inlet flow rate and channel width are 3, 0.10 m⋅s⁻¹ and 3 mm, respectively, LCPs exhibit excellent temperature control performance with low energy consumption for blade battery packs. Even under the harshest working condition with an ambient temperature of 35.0 °C and a discharge rate of 3 C, the maximum temperature and temperature difference of the battery packs can be controlled at 29.9 and 3.14 °C, respectively, which are both lower than that using LCPs with conventional serpentine channels. Additionally, its energy consumption is greatly reduced from 113.4 to 15.7 J.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"258 ","pages":"Article 128330"},"PeriodicalIF":5.8,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922420","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":"Round robin study on thermophysical properties of thin films using four measurement techniques","authors":"Yanhui Zhang ,&nbsp;Jiahao Lu ,&nbsp;Hao Zhan ,&nbsp;Jingchao Li ,&nbsp;Dazhi Hou ,&nbsp;Qinyi Li ,&nbsp;Gang Li ,&nbsp;Yingjun Liu ,&nbsp;Jianli Wang","doi":"10.1016/j.ijheatmasstransfer.2026.128328","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128328","url":null,"abstract":"<div><div>Accurate measurement of the thermophysical properties of micrometer-scale films is essential for advancing the thermal science of materials. However, current techniques often struggle to rapidly and reliably characterize their thermal conductivity and diffusivity. To address this challenge, a round robin test was conducted using several widely adopted photothermal and thermoelectric methods, including micro-thermocouple (micro-TC)– and lock-in thermography (LIT)–based laser-spot-periodic-heating methods, laser flash analyzer (LFA), and the Hot Disk technique. Five representative films were evaluated, including isotropic 304 stainless steel (SUS304) and copper (Cu) films, as well as anisotropic materials such as polyimide (PI), graphene (GPE), and highly oriented bamboo fiber (BF) composites. Comparative analysis highlighted key differences in measurement outcomes, reflecting the fundamental limitations and strengths of each technique. For the LIT technique, limited spatial resolution and the accuracy constraints of infrared cameras led to significant deviations in cross-plane thermal diffusivity measurements for Cu and PI films. The LFA method proved suitable for measuring in-plane thermal diffusivity in high-conductivity films and cross-plane diffusivity in low-conductivity films. Nonetheless, its circular heat flow geometry prevented reliable resolution of in-plane anisotropy in BF composites. The slab mode of the Hot Disk technique enabled effective in-plane thermal diffusivity measurements for SUS304, but the values obtained for Cu films and GPE composites showed significant deviations. When applied in thin film mode to PI films, the Hot Disk technique enabled measurement of the cross-plane thermal conductivity. In the bulk mode, the technique was limited to determining only the effective bulk thermal diffusivity of BF composites. These findings underscore the importance of selecting appropriate techniques tailored to film material properties and geometry, providing valuable insights for improving thermophysical characterization of emerging thin-film materials.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"258 ","pages":"Article 128328"},"PeriodicalIF":5.8,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922259","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":"Fluid-resonant oscillations in a cavity flow with a honeycomb stack","authors":"Hiroshi Yokoyama,&nbsp;Ryotaro Fukumoto,&nbsp;Takashi Kuraishi","doi":"10.1016/j.ijheatmasstransfer.2025.128323","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.128323","url":null,"abstract":"<div><div>To control and utilize aerodynamic sound energy through thermoacoustic effects, this study investigates the effects of a multi-channel stack on fluid-resonant oscillations in a cavity flow. Compressible flow simulations were conducted for a cavity containing a honeycomb stack with an incoming turbulent boundary layer, and the results were validated through wind tunnel experiments. The effects of the vertical position of the stack relative to the cavity depth on the self-sustained oscillations and heat-pumping effects were examined. The placement of the stack significantly affected the acoustic resonance within the cavity, with mode shifts observed in shear layer oscillations at specific stack positions. When the stack was positioned near the cavity bottom, an effective heat flow was induced through the stack due to thermoacoustic heat pumping, resulting in a temperature gradient between the stack ends. These findings demonstrate the possibility for controlling self-sustained oscillations in cavity flows using a honeycomb stack, highlighting energy conversion mechanisms between sound and heat.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"258 ","pages":"Article 128323"},"PeriodicalIF":5.8,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922258","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":"Physics-informed hierarchical neural operator for solving inverse problem of unsteady heat conduction","authors":"Shan Ding,&nbsp;Yongfu Tian,&nbsp;Lang Qin,&nbsp;Hongxiang Ma,&nbsp;Rui Yang","doi":"10.1016/j.ijheatmasstransfer.2026.128335","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128335","url":null,"abstract":"<div><div>Inverse heat conduction problems (IHCPs) are fundamental to many disciplines and engineering applications, yet remaining notoriously challenging issues. In recent years, the rapid advancement of artificial intelligence has promoted the interdisciplinary field “AI for Science”, which offers a novel research paradigm for addressing IHCPs. This study focuses on heat source inversion and the reconstruction of unsteady heat conduction processes from temperature observations. We propose a novel physics-informed hierarchical neural operator (PIHNO) that enables high-precision mapping from discrete temperature measurements to continuous representations of both the heat source and the solution. Notably, it requires only discrete temperature data from a single time slice to reconstruct the full spatiotemporal field. Architecturally, PIHNO comprises two submodules: a solution model and a source model, each built upon the DeepONet framework. Inspired by multi-grid strategies in numerical method, we introduce a hierarchical network structure that enhances the network depth, representation capacity, and convergence speed of the submodules. The two submodules are coupled through the heat conduction equation, ensuring compliance with physical principles. Furthermore, we introduce a new variation loss term that effectively mitigates the imbalance problem of the governing equation loss term among samples, improves accuracy and efficiency, and strengthens the generalization under diverse conditions. We evaluate the proposed method through three numerical experiments, where heat sources are modeled as smooth Gaussian functions, non-parametric Gaussian random fields, and highly discontinuous piecewise functions, respectively. The results demonstrate that PIHNO exhibits outstanding performance, enabling accurate simultaneous reconstruction of both heat sources and temperature fields across varying source distributions. It takes 0.2 s for temperature field reconstruction and 0.08 s for heat source identification, which is orders of magnitude faster than traditional numerical methods. Moreover, the model shows strong robustness even under significant levels of measurement noise.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"258 ","pages":"Article 128335"},"PeriodicalIF":5.8,"publicationDate":"2026-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922257","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 molecular dynamics simulation study on the gas binary diffusion coefficient of PODEn/N2 and its application in evaporating spray simulation","authors":"Xuehao Zhang ,&nbsp;Yanzhi Zhang ,&nbsp;Feilong Chen ,&nbsp;Ming Jia ,&nbsp;Tiemin Xuan","doi":"10.1016/j.ijheatmasstransfer.2026.128325","DOIUrl":"10.1016/j.ijheatmasstransfer.2026.128325","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The gas binary diffusion coefficient (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) between fuels and ambient gases plays a critical role in accurately predicting the characteristics of droplet evaporation and flame dynamics. Given the limited availability for measurement data on &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; of polyoxymethylene dimethyl ether (PODE&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;), molecular dynamics (MD) simulations were utilized in conjunction with the Green–Kubo (GK) method to systematically assess &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; of PODE&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; in a nitrogen (N&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) environment across temperatures ranging from 500 to 1500 K and pressures from 1 to 100 bar for the first time. The MD simulation results were utilized to optimize the Lennard-Jones (LJ) parameters of the Hirschfelder–Bird–Spotz (HBS) equation, including the characteristic length (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) and the well depth (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ɛ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) for PODE&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; at atmospheric pressure. Moreover, an improved Takahashi correlation was proposed using MD results to accurately predict &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; at high pressures. This combined approach provides a more accurate and broadly applicable parameter framework for predicting the &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; of PODE&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;/N&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; systems than conventional empirical correlations. In addition, the influence of &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; on single droplet and spray evaporation was examined by single droplet and spray simulations, validated against in-house optical measurements. The results demonstrate that employing &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; obtained from MD simulations significantly improves the accuracy of evaporation rate, gas-phase penetration, and mixing predictions compared to those based on the empirical correlation. This further validates the applicability of MD-based transport property predictions and highlights the importance of accurate &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; in sing","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"258 ","pages":"Article 128325"},"PeriodicalIF":5.8,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922422","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":"Study on the influence of uneven flow field distribution on the temperature field of the LCIPM","authors":"Zutao Chen,&nbsp;Zhongjun Yu,&nbsp;Fanqing Meng,&nbsp;Juntan Yang,&nbsp;Jia Fu","doi":"10.1016/j.ijheatmasstransfer.2025.128321","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.128321","url":null,"abstract":"<div><div>As propulsion system integration requirements increase, the design of an efficient cooling system becomes critical to improving motor energy density. The fan of the air cooling system is placed on the top of the motor, and the new air-cooled structure with air intake on both sides and air exhaust in the middle is one of the measures commonly used in large-capacity induction propulsion motors (LCIPM).</div><div>However, due to the incomplete symmetry of the air cooling system, the uneven temperature distribution of the motor is gradually apparent. To solve this problem, the air cooling system is optimized, and the influence law of different stator back ventilation areas on the maximum temperature and pressure rise of the motor is investigated. Then, the distribution law of the air volume along the axial and circumferential directions is obtained by using the full-domain flow field model. Combined with the analysis results of air volume distribution and motor losses, the fluid-solid coupling simulation method is used to investigate the influence of uneven cooling air distribution on the temperature field of the motor. The results show that the maximum temperature of the stator end winding can be reduced by 13 K by increasing the stator back air duct, and the optimal size range of the back air duct is determined. The temperature distribution of the motor is obtained by utilizing the fluid-solid coupling periodic model, and the maximum temperature difference in the circumferential direction of the winding is up to 35 K. Finally, the experimental platform is built to verify the circumferential inhomogeneity of the temperature distribution. In this paper, the non-uniform distribution characteristics of the internal flow field and temperature field of LCIPM are demonstrated in detail. The research methods and conclusions provide an effective reference for the design and optimization of similar large-capacity motors.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"258 ","pages":"Article 128321"},"PeriodicalIF":5.8,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881649","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":"Convective mass transfer boundary conditions","authors":"S.B. Beale","doi":"10.1016/j.ijheatmasstransfer.2025.128311","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.128311","url":null,"abstract":"<div><div>The prescription for convective mass transfer boundary conditions is derived in a linearized form as a function of the mass fraction, with the mixture convection flux and the transferred substance-state as the coefficient and value, respectively. It is shown that all the basic boundary conditions of computational fluid dynamics; inlet, outlet, wall, etc. may be essentially seen as specific instances derived from this simple prototype. Details of how to calculate boundary values and gradients from the driving force are provided. In addition to being applicable to mass transfer problems, where the dependent variable is mass fraction or concentration; the theory is also relevant to heat and momentum transfer for fluid flow problems with injection/suction along the boundaries. The key concepts of the convective mass transfer boundary condition are derived for a basic finite-volume cell, with a critical discussion of the magnitude of the errors that are introduced when simplified formulations are employed at the boundaries. This study bridges and extends traditional mass transfer theory and best practices in computational fluid dynamics.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"258 ","pages":"Article 128311"},"PeriodicalIF":5.8,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881237","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":"Numerical investigation on steady and dynamic operation characteristics of PEM water electrolyzer considering gas-water velocity differences in the flow channel","authors":"Boshi Xu ,&nbsp;Xun Zhu ,&nbsp;Yang Wang ,&nbsp;Jun Li ,&nbsp;Dingding Ye ,&nbsp;Yang Yang ,&nbsp;Qiang Liao","doi":"10.1016/j.ijheatmasstransfer.2025.128318","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.128318","url":null,"abstract":"<div><div>Proton exchange membrane (PEM) water electrolyzer stands out as a promising hydrogen production technology, thanks to its excellent dynamic adaptability and high current density. Massive gaseous product is produced at high current density, presenting challenges to the two-phase flow and thermal management. However, the gaseous and liquid velocity difference is always neglected in previous computational model, thereby underestimating gas saturation and temperature near the channel outlet. Herein, a three-dimensional, two-phase, full electrolyzer model is developed to study the internal characteristics. The commonly used assumption of equal liquid and gas velocity in flow channel is abundanded by solving a separate phase saturation equation. With the help of this accurate model, both steady and dynamic behaviors of PEM electrolyzer are simulated and discussed. It is found that the gas velocity in channel can reach 4.5 times higher than that of liquid phase at high current densities. It is also recommended to maintain the porous transport layer (PTL) hydrophobicity higher than that of catalytic layer for better gas removal. To further examine the model, the electrolyzer performance is investigated under the photovoltaic and wind inputs. Compared with the photovoltaic scheme, the specific energy consumption of the electrolyzer operating under wind power scheme is lower. This work provides new insight into parameters' behaviors under both steady operation and fluctuating inputs.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"258 ","pages":"Article 128318"},"PeriodicalIF":5.8,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881239","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":"Heat transfer at the contact line of an evaporating meniscus observed by fluorescence thermal microscopy","authors":"Kenta Hatanaka ,&nbsp;Muku Fukamachi ,&nbsp;Yohei Sato ,&nbsp;Tomohide Yabuki","doi":"10.1016/j.ijheatmasstransfer.2025.128303","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.128303","url":null,"abstract":"<div><div>Heat and mass transfer at the contact line, where solid, liquid, and vapor phases meet, is a key phenomenon that influences both overall heat transfer and interface dynamics during liquid-vapor phase-change processes such as boiling, condensation, droplet and thin-film evaporation, and capillary-driven flows. However, direct measurements have been challenging due to the extremely small spatial scales involved. In this study, an ultrathin (0.17 μm) temperature-sensitive paint (TSP) layer was developed and integrated with an inverted fluorescence microscope to construct a fluorescence thermal microscope capable of resolving wall temperature distributions with submicron spatial resolution. The liquid film thickness distribution was also measured using an interferometer. In the contact line region, a steep wall temperature drop associated with intense evaporation was observed, with the maximum local heat flux reaching ∼32 kW/m², far exceeding the applied heat flux of 1.2 kW/m². Comparison of the heat fluxes evaluated from the wall temperature and the liquid film thickness revealed that the heat flux distribution near the contact line can be explained by accounting for the one-dimensional heat conduction resistance within the liquid film (while convection can be neglected), the interfacial thermal resistance, and the two-dimensional heat conduction in the substrate. The results further showed that the measured surface heat flux can be consistently explained by adopting an evaporation coefficient that is significantly smaller than unity and takes a value below 0.5 for the interfacial thermal resistance derived from the kinetic theory of gases.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"258 ","pages":"Article 128303"},"PeriodicalIF":5.8,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881651","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}