International Journal of Heat and Fluid Flow最新文献

{"title":"Numerical study of flow and heat transfer performance in a novel microchannel under pulsating flow conditions","authors":"Chunquan Li,&nbsp;Jirong Huang,&nbsp;Yilong Hu,&nbsp;Cailin Li,&nbsp;Hongyan Huang","doi":"10.1016/j.ijheatfluidflow.2025.110228","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110228","url":null,"abstract":"<div><div>This paper presents a numerical study of the flow and heat transfer performance of a trapezoidal cavity rib-double rectangular circular fin microchannel heat sink (TR-DRRF) combined with a pulsating fluid. The SIMPLEC algorithm is adopted for the pressure–velocity coupling using second order upwind discretization equations. The TR-DRRF microchannel is analyzed in comparison with straight rectangular microchannel (SR), trapezoidal cavity fin microchannel (TR) and trapezoidal cavity fin-single rectangular circular fin microchannel (TR-SRRF). Results indicate that the dual rectangular circular fins of the TR-DRRF significantly increase the fluid–solid interface area, disrupt thermal boundary layer development, and alter flow field distribution. At Reynolds number (Re) = 400, its maximum temperature (<span><math><msub><mrow><mi>T</mi></mrow><mrow><msub><mrow></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></mrow></msub></math></span>) is reduced by 48 K, 15.8 K, and 5.96 K compared to SR, TR, and TR-SRRF, respectively. while the Nusselt number (Nu) increased by 88.72%, 41.76%, and 13.03%, respectively. The performance evaluation criterion (PEC) improved by over 7% compared to the other three designs. The introduction of pulsating flow significantly enhances the overall thermal performance of TR-DRRF compared to steady flow at the same Re number. The core mechanism involves the sustained development of the flow boundary layer and the generation of secondary flow/counterflow. Among these, square-wave pulsed flow exhibits the most effective heat transfer enhancement. Pulsation parameters exert distinct effects: frequencies in the range of 0.2–5 Hz impair heat transfer, whereas those in the range of 5–70 Hz enhance it. Increasing frequency enhances overall heat dissipation performance (PEC outperforms steady flow at f <span><math><mo>&gt;</mo></math></span> 10 Hz). Increasing amplitude (0.2–1.2 m/s) enhances heat transfer (reducing <span><math><msub><mrow><mi>T</mi></mrow><mrow><msub><mrow></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></mrow></msub></math></span> by up to 2.1 K) but increases pressure loss. Only when amplitude <span><math><mo>&lt;</mo></math></span> 0.7 m/s does the overall performance surpass steady flow.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110228"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-scale analysis of solute dispersion in free and forced convection flow between two parallel plates filled with a porous medium","authors":"Aruna A,&nbsp;Swarup Barik","doi":"10.1016/j.ijheatfluidflow.2025.110234","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110234","url":null,"abstract":"<div><div>This study investigates the transverse concentration distribution of contaminant transport in free and forced convective flow within a parallel plate filled with a porous medium. The solute undergoes irreversible boundary reactions at the plates. Most previous studies explored similar configurations in free and forced convective flows by incorporating magnetic effects. However, our study introduces a porous medium, which more accurately reflects real-world scenarios, such as pores in particles within flowing rivers or other environments. We develop an analytical solution of the dispersion coefficient, mean and transverse concentration using a multi-scale technique. The present study examines the effects of Grashof number (<span><math><mi>G</mi></math></span>), porous parameter and relative viscosity in the presence of boundary absorptions on the solute dispersion. Higher porous parameter values reduce permeability, limit solute spreading, and maintain a peak in the mean concentration distribution. In porous media, a negative <span><math><mi>G</mi></math></span> enhances solute dispersion near the upper boundary, whereas a positive <span><math><mi>G</mi></math></span> influences dispersion when the lower boundary absorbs. The buoyancy forces dominate for <span><math><mrow><mi>G</mi><mo>&gt;</mo><mn>0</mn></mrow></math></span> or <span><math><mrow><mi>G</mi><mo>&lt;</mo><mn>0</mn></mrow></math></span>, driving the flow toward the heating or cooling plates and intensifying non-uniformity in the transverse concentration distribution. This effect becomes more significant with higher porosity and viscosity, as the porous medium reduces permeability and increases resistance to fluid motion. When boundary reactions are considered in the presence of a porous medium under free and forced convection, they cause uneven solute distribution as the walls absorb solute. A higher porous parameter increases resistance to fluid flow, which amplifies concentration gradients and enhances non-uniformity.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110234"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybrid photovoltaic–thermal and solar thermal collectors with integrated phase change materials: toward sustainable greenhouse energy systems","authors":"Soroush Entezari ,&nbsp;Meysam Khatibi ,&nbsp;Mikhail Sorin","doi":"10.1016/j.ijheatfluidflow.2026.110268","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110268","url":null,"abstract":"<div><div>Greenhouses require substantial energy for heating, cooling, and electricity, yet current renewable solutions rarely provide all three simultaneously. Most existing systems supply either thermal or electrical output and lack integrated storage, creating mismatches between solar availability and greenhouse demand and reinforcing dependence on fossil fuels. This study addresses this problem by developing and analyzing a hybrid photovoltaic–thermal (PVT) and solar thermal (ST) collector system integrated with phase change materials (PCMs) for combined power generation and heat storage in greenhouse applications. A three-dimensional numerical model examines the effects of PCM type (RT21, RT31, RT35) and heat transfer fluid flow rate under typical summer conditions in Sherbrooke, Québec, Canada. Results indicate that low-melting PCMs (RT21) achieve rapid phase change before solar noon, offering early-day cooling but limited afternoon buffering. Conversely, higher-melting PCMs (RT31, RT35) extend heat absorption throughout peak irradiance, optimizing PV thermal regulation. Parametric analysis reveals that reduced HTF flow rates maximize PCM utilization and outlet temperatures, whereas higher flow rates prioritize electrical stability. Exergy results indicate a fundamental trade-off: RT21 maximizes daily-average thermal exergy through superior temperature gradients, while RT35 optimizes electrical exergy by maintaining lower cell temperatures. Increasing HTF flow rate enhances electrical exergy but reduces thermal exergy by lowering the temperature level of the delivered heat. A 100 m² installation yields approximately 455 kWh/day of thermal energy and 35.5 kWh/day of electricity (July/August), satisfying nearly all thermal loads and 30–34% of electrical demand. This configuration achieves a significant mitigation of 77–78 kg CO₂e/day, primarily through the displacement of carbon-intensive natural gas heating.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110268"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 effect of composite cement-based materials on the heat loss of geothermal wellbores","authors":"Kai Wei ,&nbsp;Ao Wang ,&nbsp;Desheng Wu ,&nbsp;Hao Chen ,&nbsp;Yulong Liu","doi":"10.1016/j.ijheatfluidflow.2026.110257","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110257","url":null,"abstract":"<div><div>Geothermal energy is a widely distributed, high-potential, stable, and reliable non-carbon clean renewable energy source, playing a critical role in energy transition and low-carbon development. Geothermal wells are the primary technical means for geothermal energy extraction. As the core component of geothermal exploitation, a geothermal well consists of a multilayer composite system comprising the casing, cement sheath, and surrounding formation, within which heat transfer processes are highly complex. In this study, a heat transfer model for the casing–cement sheath–formation coupled system is established, together with a thermal conductivity evaluation model for cement-based composites. Numerical simulations are performed to investigate the effects of key influencing factors—including fluid flow conditions, thermophysical properties of the casing and cement sheath, and thermal properties of cementitious composites—on the heat extraction performance of geothermal wells. The results demonstrate that the thermal conductivity of the cement sheath has a significant impact on heat extraction capacity. Reducing the cement sheath thermal conductivity effectively increases the wellhead production temperature, decreases wellbore heat loss, and mitigates the influence of formation parameter uncertainty under different formation conditions. Furthermore, incorporating thermal insulation materials such as glass beads, slag microspheres, and aerogel particles into the cement sheath markedly lowers its thermal conductivity, with aerogel particles exhibiting the most pronounced effect, achieving a reduction of approximately 30%. The proposed models and findings provide theoretical support and technical guidance for optimizing geothermal well design and enhancing the efficiency of geothermal energy exploitation.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110257"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146169969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geometric confinement and fluid properties effects on stability and heat transfer of thermal convection in lateral heated cavities","authors":"Hua Hu ,&nbsp;Juan-Juan Qin ,&nbsp;Lai-Yun Zheng ,&nbsp;Xu-Long Li ,&nbsp;Bing-Xin Zhao","doi":"10.1016/j.ijheatfluidflow.2026.110312","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110312","url":null,"abstract":"&lt;div&gt;&lt;div&gt;A numerical study is performed to investigate two-dimensional natural convection in a laterally heated cavity, with particular emphasis on the coupled effects of the aspect ratio (&lt;span&gt;&lt;math&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;), Rayleigh number (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), and Prandtl number (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;). The simulations cover mainly the ranges &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;6&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;01&lt;/mn&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;01&lt;/mn&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. A fourth-order compact finite-difference scheme combined with a third-order TVD Runge–Kutta time integration is employed to ensure numerical stability and adequate resolution of unsteady flow features. The results reveal that heat transfer is strongly influenced by the Prandtl number. As &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; increases, the flow transitions from unsteady to steady behavior and the overall heat transfer is enhanced. For low-Prandtl-number fluids (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), such as gases and liquid metals, nonlinear solution bifurcations emerge, becoming increasingly pronounced at larger aspect ratios and higher Rayleigh numbers. The onset of unsteadiness is associated with a critical Rayleigh number &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, marking the transition from steady to unsteady convection. Scaling analyses show that &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; for air and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;7&lt;/mn&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; for water, indicating a reduced sensitivity to geometric confinement for high-&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; fluids. The aspect ratio is found to exert a non-monotonic influence on heat transfer. The average Nusselt number (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;av&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) attains its maximum at an optimal aspect ratio &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; that shifts toward smaller values as &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; increases. Additionally, the heat transfer follows a power-law dependence on the Rayleig","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110312"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 and ablation behaviors of the C/SiC-HfB2-HfC composite leading-edge strut in hypersonic air-breathing engine combustor environment","authors":"Zheng Zhao ,&nbsp;Jiangyi He ,&nbsp;Running Wang ,&nbsp;Tingting Jing ,&nbsp;Xing Sun ,&nbsp;Jiaping Zhang","doi":"10.1016/j.ijheatfluidflow.2026.110261","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110261","url":null,"abstract":"<div><div>Struts are usually adopted in hypersonic engines for efficient fuel injection. Sufficient thermal protection is need for injection struts under extremely high temperature gas scouring environment. The objective of this study is to verify the reliability of the C/SiC-HfB₂-HfC composite leading-edge strut under Ma6 engine combustor operation conditions. The heat transfer and ablation behaviors of the strut were investigated numerically and experimentally. The experimental results demonstrated that, under conditions of maximum temperature of ∼2800 K and maximum transient heat flux of ∼6 <span><math><mrow><mi>M</mi><mi>W</mi><mo>/</mo><mi>m</mi></mrow></math></span> ², only minor scouring marks were found at specific locations on the composite leading edge of the strut. Microscopic morphology analysis revealed that the ablation damage to the strut was predominantly concentrated at the leading edge stagnation point, with the maximum ablation depth being approximately 760 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span>. Furthermore, the solid-phase HfO₂ produced by the oxidation of ultra-high temperature phases such as HfC and HfB₂ can effectively fix the SiO₂ in the oxide layer, thereby reducing the ablation rate of the leading edge.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110261"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance prediction and optimization method of DIR-SOFC based on GA-optimized BP neural network: A case study of multi-component fuel","authors":"Jianfei Zhang,&nbsp;Weiwen Chen,&nbsp;Guomeng Wei,&nbsp;Zhiguo Qu","doi":"10.1016/j.ijheatfluidflow.2026.110254","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110254","url":null,"abstract":"<div><div>The direct internally reformed solid oxide fuel cell (DIR-SOFC) has the advantages of wide fuel adaptability and high power generation efficiency. Rapid performance prediction and optimization methods play a very important role in reducing performance improvement of SOFC. In this paper, a DIR-SOFC performance prediction and optimization method based on GA-optimized BP neural network was proposed. Using multi-component fuel as a case, 2060 analysis samples were established by 3D numerical simulation, and the current density and temperature of the DIR-SOFC under different fuel components were predicted and optimized by the proposed method. The results show that this method has the advantages of strong generalization ability, high prediction accuracy and fast calculation speed. Aiming for higher current density and lower maximum temperature gradient, the method is applied to achieve optimization combination of fuel components (H₂O, NH₃, H₂, CO, CH₄). At an operating voltage of 0.7 V, the optimal fuel ratio is determined as 0.6% H₂O, 25.6% H₂, 29% CO, 29.4% CH₄ and 15.4% NH₃. The current density is 3336 A·m⁻² and the maximum temperature gradient is 169618 K·m⁻¹. In addition, the weight analysis method was used to study the influence degree of fuel composition on power generation performance. It is found that increasing the volume fraction of H₂O and NH₃ in the fuel reduces the power generation performance, while increasing the volume fraction of H₂, CO and CH₄ in the fuel improves the power generation performance. Increasing the volume fraction of H₂O decreases the maximum temperature gradient while other gases increase it. These conclusions are consistent with the results obtained by the prediction method, which proves the consistency of the proposed method with the physical mechanism. This study has guiding significance for optimizing the operating conditions of DIR-SOFC.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110254"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 modelling of heat and mass transfer during vapour condensation in porous media: Insights from neutron tomography","authors":"Arash Nemati ,&nbsp;Philippe Séchet ,&nbsp;Bratislav Lukić ,&nbsp;Matthieu Briffaut","doi":"10.1016/j.ijheatfluidflow.2026.110293","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110293","url":null,"abstract":"<div><div>Moisture condensation in porous media influences heat and mass transport in natural and engineered systems, with implications for energy, environmental, and material applications. This study presents a new framework for analysing coupled heat and mass transfer during vapour condensation in porous materials. The Darcy-scale model, formulated under local thermal equilibrium, incorporates multiphase flow, phase change, and heat transport through standard capillary and permeability relationships. A finite-volume solver was implemented in OpenFOAM to couple heat and vapour transport via a temperature-dependent vapour saturation relationship. An analytical solution for the immobile case, where the condensed liquid remains stationary, defines an effective Péclet number that quantifies the competition between advective and diffusive transport of both heat and vapour. Together with the capillary number (relevant in mobile regimes), representing the balance between pressure and capillary forces, these parameters help classify the condensation regimes. Simulation results reveal that near the condensation front, water flux is driven by capillarity, while farther behind, pressure gradients from vapour injection dominate. Higher effective Péclet numbers yield sharper condensation fronts, while higher capillary numbers enhance liquid spreading near the front. Validation using time-resolved neutron tomography and prior numerical results confirms the ability of the model to capture key condensation mechanisms. The framework also extends to heterogeneous media with fractures, where condensation concentrates near the fracture and gradually diffuses into the surrounding matrix.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110293"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation into the effects of crimp morphology on heat transfer and flow of high-frequency welded finned tubes","authors":"Chunxue Zhang ,&nbsp;Wenchun Jiang ,&nbsp;Huibo Meng ,&nbsp;Yiliang Jia ,&nbsp;Yucai Zhang ,&nbsp;Shan-Tung Tu","doi":"10.1016/j.ijheatfluidflow.2026.110296","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110296","url":null,"abstract":"<div><div>Crimped spiral finned tubes (CSFTs) are increasingly adopted in air coolers owing to advances in high-frequency resistance welding technology. Targeting the unique crimped morphology of CSFTs, this study innovatively quantifies the effects of crimping parameters on heat transfer and flow resistance, while simultaneously examining the influence of fin pitch and fin thickness on both plain spiral finned tubes (PSFTs) and CSFTs. Results show that PSFTs benefit more from fin pitch optimization, achieving up to 16.8% enhancement in <em>Nu</em> and 13.8% in the comprehensive performance index <em>ζ</em>, whereas CSFTs exhibit only marginal improvements accompanied by higher frictional losses. Nevertheless, introducing crimp amplitude <em>C_a</em> and crimp frequency <em>C_fd</em> enables further enhancement for CSFTs. Variance analysis demonstrates that <em>C_a</em> and <em>C_fd</em> contribute almost equally to <em>Nu</em> (48.7% vs. 47.8%), whereas <em>C_a</em> imposes a stronger penalty on the friction factor <em>f</em>. Considering the trade-off between amplitude and frequency imposed by manufacturing constraints, a novel optimization strategy is proposed: prioritize increasing crimp frequency while appropriately limiting crimp amplitude. In addition, predictive models for <em>Nu</em> and <em>f</em> are established using <em>Re</em>, fin pitch, fin thickness, <em>C_a</em> and <em>C_fd</em> as inputs. Artificial neural networks outperform regression models, with prediction errors below 5%, demonstrating strong accuracy and practical applicabilit. This study provides practical guidance into heat transfer enhancement for high-efficiency heat exchange systems employing CSFTs.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110296"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of thermal–hydraulic characteristics of cut-out type flying-wing fins","authors":"Xin Qi ,&nbsp;Pengcheng Zheng ,&nbsp;Zipei Zhang ,&nbsp;Wenqiang Suo ,&nbsp;Shiqun Liu ,&nbsp;Xiangshu Lei ,&nbsp;Aiyan Li ,&nbsp;Peng Yang ,&nbsp;Yingwen Liu","doi":"10.1016/j.ijheatfluidflow.2026.110290","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110290","url":null,"abstract":"<div><div>The study investigates the potential of a cut-out structure to enhance the heat transfer and flow characteristics of fins in the flying-wing condenser for refrigerator. The proposed cut-out structure is designed to address the limitations of conventional methods for strengthening heat transfer accompanied by an increase in flow resistance. The introduction of a cut-out structure facilitates the flow of cooling air from the front part to the rear area of the fins, thereby enhancing the heat transfer efficiency for rear fins. Additionally, it minimizes the collision between the airflow and the fins, enabling the flying-wing fins to achieve augmented heat transfer and reduced flow resistance simultaneously. The findings of the study demonstrate that the heat exchange rate of the flying-wing fins is enhanced by 7% and the flow resistance is reduced by 20.8% following the integration of the cut-out. Concurrently, an augmentation in the cut-out height and length of the fins resulted in a concurrent decrease in both heat exchange rate and flow resistance. Furthermore, an analysis of the field synergy angle and local convective heat transfer coefficient (LCHTC) of the different cut-out type flying-wing fins reveals that the introduction of the cut-out leads to a significant enhancement in the synergy between the velocity field and the temperature field. Concurrently, the LCHTC exhibits a “high and low” distribution pattern within the fin channel, with the LCHTC on the right side being notably higher than that on the left side.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110290"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146169957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}