International Journal of Heat and Mass Transfer最新文献

{"title":"A study of steady laminar diffusion flames at buoyancy-induced low stretch rates in a spherical porous gas burner","authors":"Shangqing Tao ,&nbsp;Jun Fang ,&nbsp;Yuhang Chen ,&nbsp;Yahong Yang ,&nbsp;Wei Chu ,&nbsp;Jingwu Wang ,&nbsp;Wenlong Wang ,&nbsp;Longhua Hu","doi":"10.1016/j.ijheatmasstransfer.2025.127907","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127907","url":null,"abstract":"<div><div>The steady combustion behavior and stability range of methane, ethylene, and propane in a low stretch spherical counterflow burner were investigated. Ethylene had the widest fuel mass flux (<span><math><msup><mover><mi>m</mi><mo>˙</mo></mover><mrow><mo>″</mo></mrow></msup></math></span>) range of steady blue flame. A decreased buoyant stretch rate (<em>a</em>_b) reduced this steady range. The critical <span><math><msup><mover><mi>m</mi><mo>˙</mo></mover><mrow><mo>″</mo></mrow></msup></math></span> at the extinction limit of the low stretch flames were lower than that of the normal gravity, and ethylene had the lowest critical <span><math><msup><mover><mi>m</mi><mo>˙</mo></mover><mrow><mo>″</mo></mrow></msup></math></span> at the lowest <em>a</em>_b, indicating a wider steady fuel mass flux range for ethylene and a greater fire risk for microgravity low stretch flames. The ratio of the flame horizontal length to the vertical length (<em>l</em>_f/<em>y</em>_f) was quantified by a dimensionless parameter: <span><math><mrow><mi>P</mi><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo><mfrac><mn>4</mn><mn>5</mn></mfrac></mrow></msup><msup><mrow><mo>(</mo><mfrac><mstyle><mi>Δ</mi></mstyle><mrow><mi>F</mi><mi>r</mi></mrow></mfrac><mo>)</mo></mrow><mrow><mo>−</mo><mfrac><mn>1</mn><mn>5</mn></mfrac></mrow></msup><msup><mrow><mo>(</mo><mrow><mi>S</mi><mrow><mo>+</mo><mn>1</mn></mrow></mrow><mo>)</mo></mrow><mrow><mo>−</mo><mfrac><mn>6</mn><mn>5</mn></mfrac></mrow></msup></mrow></math></span>, which considered the combined effects of burner properties (described by Péclet number <em>Pe</em>), gravity/buoyancy effect (described by expansion parameter <span><math><mstyle><mi>Δ</mi></mstyle></math></span> and Froude number <em>Fr</em>) and fuel combustion process (described by chemical reaction characteristic parameter <em>S</em>). The flame temperature <em>T</em>_f for the fuels increased with increasing <em>u</em>_F and <em>a</em>_b, whereas <em>T</em>_f increased slowly when <em>u</em>_F was greater than the sooting limit <em>u</em>_F due to incomplete combustion with appreciable heat loss. The low stretch flame temperatures of the three fuels rank as C₂H₄&gt;C₃H₈&gt;CH₄ because of their different heats of combustion and heat losses. Both the gas-phase and solid-phase heat losses fractions were significant at low stretch rates. Solid-phase heat loss was vital to methane, which largely influenced its periodic flame hole instability near the extinction limit. This flame instability also extended the flammable range of methane at low stretch rates. This study can give instructions for microgravity combustion because a flame is usually initiated at low stretch rates under microgravity.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127907"},"PeriodicalIF":5.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264351","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":"Data-driven modeling and experimental validation of the laser sintering process for the printed silver nanoparticles ink for in-space manufacturing of printed electronics","authors":"Sagar Kumar Verma ,&nbsp;Ellie Schlake ,&nbsp;Nirmala Kandadai","doi":"10.1016/j.ijheatmasstransfer.2025.127889","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127889","url":null,"abstract":"<div><div>The proposed work aligns with the National Aeronautics and Space Administration (NASA)’s On-Demand Manufacturing of Electronics (ODME) project plan to support a multi-material printer on board the International Space Station to demonstrate three-dimensional printing capability. Laser sintering of printed silver nanoparticles (AgNP) ink is an ideal technique for NASA’s ODME to be integrated with printers for NASA’s ODME mission. In this work, we compare the experimental data for optimized laser sintering parameters for two types of AgNP inks: aqueous-based and polymer-based inks. A data-driven simulation model was developed to optimize the laser sintering process, including the transient heat transfer model with the phase change of the metal nanoparticle ink from solidus to liquidus. This experiment and simulation study discuss the laser sintering parameters for the printed AgNP ink on various substrates, including glass, Kapton, and alumina. We study the effect of various sintering parameters such as laser power, laser scanning speed, laser spot sizes, and laser wavelengths. The simulation discusses the variations of maximum sintering temperature and heat distribution in radial and transverse directions through the Ag layer and substrate during laser sintering and compares it with the experimental findings. The proposed data-driven model utilizes experimentally examined temperature-dependent thermal conductivity, film porosity-dependent heat capacity, and the absorption coefficient as wavelength-dependent optical properties of AgNP ink as input data. Our work compares the trends of modelled surface temperature against experimentally determined electrical resistivity of the laser sintered film.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127889"},"PeriodicalIF":5.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264298","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 and pore-scale simulation study on CO2 diffusion in porous media saturated by brine and oil","authors":"Yongjie Chen ,&nbsp;Wei Liu ,&nbsp;Lin Du ,&nbsp;Wei Zou ,&nbsp;Baolun Niu ,&nbsp;Yang Xu ,&nbsp;Yanchao Li ,&nbsp;Songcai Han ,&nbsp;Lanxiao Hu","doi":"10.1016/j.ijheatmasstransfer.2025.127930","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127930","url":null,"abstract":"<div><div>CO₂ diffusion in porous media saturated by brine and oil plays an important role in both enhanced oil recovery (EOR) and carbon capture, utilization and storage (CCUS). However, it is challenging to thoroughly investigate the diffusion of CO₂ in porous media with varied water saturations using numerous experiments. In this study, we develop a pore-scale numerical simulation method to predict CO₂ effective diffusion coefficient (<em>D_eff</em>) in cores with different water saturations. First, a new method for determining the CO₂ effective diffusion coefficient in cores with different water saturations is developed by coupling axial constant-volume diffusion (ACVD) experiments with mathematical models. Using this method, we determine <em>D_eff</em> in cores with water saturations ranging from 0 % to 100 %. In the numerical simulations, a model is developed to investigate CO₂ diffusion in porous media. Subsequently, history matching of the CO₂ diffusion amount in porous media is conducted to determine the <em>D_eff</em> in these media with different water saturations. We validate the accuracy of the pore-scale numerical model developed in this study by comparing the <em>D_eff</em> calculated using this model with those determined from experimental results. The pore-scale numerical simulations indicate that non-uniform CO₂ diffusion is prevalent in formations with various water saturations, as CO₂ preferentially diffuses into pore spaces occupied by oil. Finally, we develop a generalized <em>D_eff</em> prediction model using the Alternating Conditional Expectation (ACE) algorithm. This study may provide some new insights into CO₂ diffusion in porous media saturated by brine and oil.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127930"},"PeriodicalIF":5.8,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264299","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":"Rapid chilldown mechanism of a low thermal conductivity coating on a flat plate in a liquid nitrogen pool","authors":"Jongbin Lee ,&nbsp;Kyungwon Lee ,&nbsp;Minsub Jeong,&nbsp;Aejung Yoon","doi":"10.1016/j.ijheatmasstransfer.2025.127879","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127879","url":null,"abstract":"<div><div>This study numerically and theoretically investigated the rapid chilldown mechanism of a low-thermal-conductivity (low-<em>k</em>) coating and its impact on the boiling regime transition of a flat plate in a liquid nitrogen pool. A numerical model incorporating intermittent liquid–solid (L–S) contact was developed, and it revealed that the L–S contact induces a rapid, localized temperature drop. This temperature drop was more pronounced for low-<em>k</em> coated surfaces than for the bare ones, resulting in a faster regime transition. Specifically, the transition was triggered when the L–S contact region locally reaches the minimum heat flux temperature, with thicker plates and thinner coatings requiring a longer regime transition times. Notably, the numerical calculations indicated that the optimal coating thickness for minimizing the chilldown time is 170 µm, regardless of stainless-steel plate thickness. To theoretically reveal the mechanism behind the fast regime transition induced by the low-<em>k</em> coating, a closed-form expression for predicting the regime transition time was derived, identifying four nondimensional parameters that govern the transition. This expression explicitly showed that regime transition is influenced not only by the thermal effusivity, conductivity, and thickness of the coating layer but also by the thermal effusivity, diffusivity, and thickness of the metal plate. Finally, this study paves the way for a systematic approach to quantify the effects of these parameters and provides a design guideline for selecting the appropriate coating thickness to regulate the chilldown time.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127879"},"PeriodicalIF":5.8,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264253","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 Comprehensive Experimental Database and Novel Onset Criterion for Heat Transfer Deterioration in Vertical Upward Supercritical CO₂","authors":"Haifan Liao ,&nbsp;Zhenghui Hou ,&nbsp;Chaofan Yang ,&nbsp;Kuang Yang ,&nbsp;Chaojie Xing ,&nbsp;Haijun Wang","doi":"10.1016/j.ijheatmasstransfer.2025.127906","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127906","url":null,"abstract":"<div><div>This study systematically evaluates and advances methods for identifying heat transfer deterioration (HTD) and its onset in vertical upward flow of supercritical carbon dioxide (sCO₂). We compiled and rigorously curated the largest experimental dataset to date, comprising 47338 data points from 41 publications and covering pressure, inlet temperature, heat flux, mass flux, pipe diameter, material and lengths of heated and insulated sections; uniform screening, calibration and categorization produced 1095 directly comparable cases spanning the complete q-G and q/G-d operating space. A systematic assessment of existing identification techniques motivated the development of an improved temperature fluctuation approach, which achieves 89.2% accuracy. Comprehensive evaluation of buoyancy and thermal acceleration dimensionless groups demonstrated that no single effect parameter maintains a stable HTD threshold across all conditions, highlighting the need for multi effect coupled modeling. Finally, after reviewing nineteen classical onset criterion correlations, we introduce a data driven framework based on Buckingham Pi analysis and active subspace methods to select dominant dimensionless groups and formulate a novel onset criterion with adjustable probability thresholds that outperforms existing methods in accuracy. This work provides a high quality experimental database, refines HTD identification techniques and proposes an advanced onset criterion, thereby laying the groundwork for future standardization, online monitoring, mechanistic insight and practical engineering applications in sCO₂ heat transfer systems.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127906"},"PeriodicalIF":5.8,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264381","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":"Measurement of viscous slip coefficient on a thin wire surface in rarefied gas flows","authors":"Taiga Kawakami (川上大河) ,&nbsp;Hiroki Yamaguchi (山口浩樹)","doi":"10.1016/j.ijheatmasstransfer.2025.127914","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127914","url":null,"abstract":"<div><div>In rarefied gas flows, velocity slip phenomenon appears with increasing Knudsen number and has a strong influence on the flow field. It is important to evaluate the size of velocity slip. In this study, a novel approach was proposed to measure the viscous slip coefficient, which represents the magnitude of velocity slip in high Knudsen number flows, on the surface of a thin wire. A microchannel with coaxial-cylinders geometry consisting of a thin wire placed on the center axis of a circular microtube was prepared. Then, the mass flow rate through a gap between the thin wire and the microtube was measured using the constant-volume method. The measured results were subsequently compared with those obtained with the microtube only, i.e., without the thin wire, and the viscous slip coefficient on the thin wire was deduced by fitting the analytical mass flow rates to the measured values. From our measurements using a platinum thin wire inside a glass microtube, the viscous slip coefficients for helium and argon on the platinum surface were successfully obtained. From the viscous slip coefficients, the tangential momentum accommodation coefficients were also calculated. Our novel approach makes it possible to measure the velocity slip on metal surfaces, leading to further accumulation of the data on a wider variety of sample surfaces.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127914"},"PeriodicalIF":5.8,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264356","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 of transpiration cooling with microchannels for aerospace vehicles' leading edge","authors":"Ping Tang ,&nbsp;Jiaqi Zhang ,&nbsp;Jiping Wu ,&nbsp;Yuan Wang ,&nbsp;Fuming Yu","doi":"10.1016/j.ijheatmasstransfer.2025.127909","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127909","url":null,"abstract":"<div><div>Transpiration cooling is a promising active thermal protection strategy for hypersonic vehicles; however, its application to sharp leading edges remains challenging due to extreme heat flux, structural fragility, and inefficient coolant distribution. To address these limitations, this study proposes an innovative transpiration cooling configuration incorporating precisely designed microchannels, thereby enhancing both cooling uniformity and mechanical strength. A coupled 1D–3D computational framework is developed to capture the interactions between aerodynamic heating, internal coolant transport, and phase change, balancing numerical efficiency with accuracy. The cooling architecture is divided into two functional channel types: primary control channels that transport and pre-cool the coolant, and distribution channels that enable efficient effusion and protective film formation. Results show that the proposed system substantially reduces peak wall temperature and achieves high cooling efficiency even at Mach 8 flight conditions. Parametric analyses reveal that increasing the coolant mass flow rate from 4.0×10⁻⁶ to 5.0×10⁻⁶ kg/s improves cooling efficiency by nearly 10%, while raising the altitude from 34 km to 38 km further enhances efficiency by more than 13% due to reduced heat flux. An optimal blowing ratio of 6.83% is identified, balancing effective thermal protection with structural reliability. The findings demonstrate that transpiration cooling with microchannels offers a practical and robust solution for sharp leading-edge protection, providing valuable guidance for future reusable hypersonic vehicle design.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127909"},"PeriodicalIF":5.8,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227543","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":"Role of tissue porosity in thermal damage during microwave ablation","authors":"Teerapot Wessapan ,&nbsp;Pornthip Keangin ,&nbsp;Phadungsak Rattanadecho ,&nbsp;Nisakorn Somsuk","doi":"10.1016/j.ijheatmasstransfer.2025.127886","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127886","url":null,"abstract":"<div><div>Microwave ablation (MWA) uses electromagnetic waves to produce localized heat for tumor therapy. This research examined the influence of tissue porosity on heat transmission and thermal damage patterns during microwave ablation via numerical simulations grounded in Maxwell's equations and porous media theory. Tissue necrosis was forecasted via an Arrhenius model, dependent on temperature and exposure time. The study findings show that higher tissue porosity leads to a more diffused and elongated necrotic zone due to enhanced convective heat transfer. The heightened porosity elevates fluid velocity and enhances natural convection currents, leading to a more comprehensive heat dispersion throughout the tissue, hence complicating the regulation of the tissue ablation zone and heightening the danger of harming healthy tissues. Moreover, higher microwave power levels intensify tissue heating and convection; when combined with intrinsic tissue porosity, this broadens heat dispersion and can distort the ablation-zone geometry. These observations underscore the necessity of accounting for tissue porosity in the optimization of MWA regimens. By customizing the microwave power level and exposure time to the porous nature of tissues, clinicians can predict thermal outcomes more accurately and improve tumor targeting while minimizing harm to the surrounding tissues. This approach is promising in realizing more precise and safer MWA treatments for cancer.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127886"},"PeriodicalIF":5.8,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227547","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":"Analytical model for weld penetration prediction in finite plates with time-varying heat sources","authors":"Kanghong Zhu ,&nbsp;Weihua Liu ,&nbsp;Bowen Qi ,&nbsp;Runquan Xiao ,&nbsp;Huabin Chen","doi":"10.1016/j.ijheatmasstransfer.2025.127921","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127921","url":null,"abstract":"<div><div>The dynamic behavior evolution of the welding molten pool presents challenges due to their invisibility and difficulty of quantification. In engineering applications, the perception of weld penetration depth and width faces limited generalization, making it difficult to meet the demands of complex time-varying welding conditions in scenarios not covered by historical data. This study proposes a new analytical solution for the double-ellipsoidal heat source, extending its application scope to finite plate and time-varying heat input. Utilizing the boundary thermal effect mirroring principle and a more concise parametric equations for mirror coordinate mapping, we rederived an analytical formula for the time-varying double-ellipsoidal heat source model. High resolution accuracy and strong generalization capability of the model were validated using finite element analysis and real-world complex welding experiments, with width and depth errors under 1.0 mm. The study addresses the quantitative characterization of liquid molten pool geometric parameters (weld width and penetration depth) in complex welding scenarios, providing a scientific methodology and technical pathway for self-learning intelligent welding models and adaptive control in complex, time-varying welding conditions.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127921"},"PeriodicalIF":5.8,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264349","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":"New insights into the formation mechanisms of channel segregation in lateral solidification of alloys: A numerical study using an improved macrosegregation model","authors":"Jibai Kang ,&nbsp;Weiling Wang ,&nbsp;Miaoyong Zhu","doi":"10.1016/j.ijheatmasstransfer.2025.127912","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127912","url":null,"abstract":"<div><div>Channel segregation has been extensively studied due to its detrimental impact on alloy castings and the complex fluid-mechanical phenomena underlying its formation. While the mechanisms of channel formation in upward solidification are well understood, those in lateral solidification remain elusive due to a lack of consensus on mushy zone destabilization. To address this gap, this study develops a comprehensive macrosegregation model incorporating several novel approaches: a rate equation describing solute accumulation in the solid phase, a concentration equation system ensuring global solute conservation, and an extended liquid fraction iteration method coupling macro- and micro-segregation within a thermodynamic equilibrium framework. The model is validated against a benchmark experiment and subsequently applied to investigate channel initiation. It is found that mushy zone destabilization is not primarily caused by remelting or flow instability, as suggested in previous studies, but rather by thermal gradient that induces protrusions on the solid/liquid (S/L) interface, forming a step-like morphology. The interdendritic flow is hindered at the protrusions, promoting localized solute accumulation and hence initiating channel segregation. The effects of microstructure and thermal conditions on channel development are further explored. Channel formation is significantly suppressed when the dendrite arm spacing becomes finer, and the morphology varies with the permeability laws used. Additionally, the inclination angle of the channels relative to gravity increases with increasing temperature gradient. Channel discontinuity is associated with disturbances in the bulk liquid flow pattern. Under high temperature gradients, thermally driven circulations remain stable over long time scales, leading to well-aligned and developed channels. In contrast, increasing the cooling rate effectively suppresses channel formation. Finally, Rayleigh-number-based criteria are employed to evaluate channel formation. A critical Rayleigh number of 0.55 is identified for channel initiation, and when it exceeds 1.0, highly developed channels are more likely to form.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"256 ","pages":"Article 127912"},"PeriodicalIF":5.8,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227545","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}