International Journal of Heat and Mass Transfer最新文献

{"title":"Experimental study of local heat transfer during downward flow condensation in vertical tube-in-tube annulus channel","authors":"Jiayuan Li ,&nbsp;Jayachandran K. Narayanan ,&nbsp;Huigang Wang ,&nbsp;Finnegan O’Leary ,&nbsp;Xiaoyang Gao ,&nbsp;Carter Richmond ,&nbsp;Chirag R. Kharangate","doi":"10.1016/j.ijheatmasstransfer.2025.127805","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127805","url":null,"abstract":"<div><div>Flow condensation is an important configuration in thermal management due to its efficiency in heat dissipation offered by both convective and phase-change heat transfers. Prior studies on flow condensation in literature focus on condensate flowing inside a tube, featuring the in-tube heat exchanger configuration. However, many common heat exchangers used across applications such as the shell-and-tube type see the condensate flowing on the outside the tube, featuring the outer-tube heat exchanger configuration. In this study, we experimentally investigate the local heat transfer behavior of the outer-tube downward flow condensation in a vertical tube-in-tube condensation module. The test module features a vertical outer-tube heat exchanger with downward-flowing PF-5060 (a clear, colorless, fully-fluorinated dielectric fluid for heat transfer applications manufactured by 3M^TM) condensing outside the circular tube and upward-flowing deionized water inside the tube flowing counter-currently with the PF-5060 flow. The tests include PF-5060 mass velocity from 26.5 – 58.9 kg/m²s, water mass velocity from 330.4 – 472.8 kg/m²s, inlet pressure from 139.6 – 168.2 kPa, and inlet superheated temperature from 4.2 – 5.8°C. Fine temperature measurements are made on the exterior of the tube wall and within the water flow along the module, which are used to determine the local heat transfer coefficients along the condensation path. The result shows that heat transfer coefficient decreases sharply upstream near the inlet and then gradually declines as we move further downstream. Further, the heat transfer coefficient increases along axial locations with PF-5060 mass velocity, while it rises upstream but shows mixed trends downstream with increasing water mass velocity. Correspondingly, the channel-averaged heat transfer coefficient increases with both PF-5060 and water mass velocities, with PF-5060 showing a much stronger impact. Pressure effects are also examined, revealing that the heat transfer coefficient fluctuates, decreasing upstream and showing mixed trends downstream. Finally, common correlations for in-tube flow condensation generally underpredict the experimental heat transfer coefficients but the approaches of Nie et al., Akers et al., and Shah show better predicting capability. The results highlight distinct differences in entrained liquid distribution and associated heat transfer between in-tube and outer-tube downflow condensation.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127805"},"PeriodicalIF":5.8,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004919","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":"Natural convection heat transfer along vertical wavy surfaces with different amplitude-to-wavelength ratios","authors":"Wenqi Gu ,&nbsp;Hisanobu Kawashima ,&nbsp;Tsuneaki Ishima","doi":"10.1016/j.ijheatmasstransfer.2025.127791","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127791","url":null,"abstract":"<div><div>This study investigates steady, laminar natural convection heat transfer along a vertical isothermal plate incorporating wavy surfaces, employing both experimental and numerical approaches. The wavy surface geometry is modeled using cosine profiles with varying amplitude-to-wavelength ratios of 0.061, 0.083, and 0.167. Computational fluid dynamics (CFD) simulations based on the finite-volume method were conducted, and particle image velocimetry (PIV) technique was utilized to measure the velocity field. The results from the CFD simulations were validated through comparison with experimental measurements, exhibiting qualitative agreement. The findings indicate that the amplitude-to-wavelength ratio critically influences the air velocity distribution and convective heat transfer. Enhance velocity gradients at convex regions modestly improve heat transfer, whereas stagnation at the concave regions significantly impairs natural convection. Increasing the amplitude-to-wavelength ratios further expands stagnant regions, reducing velocity gradients adjacent the wall and weakening convection. Heat flow based on the mean heat transfer coefficient for wavy surface profiles decreases by 6.08 %, 9.56 %, and 25.95 %, compared to a flat plate. However, when the mean heat transfer coefficient was determined based on the projected length of surface profiles, heat flow improves by 0.60 %, 2.42 %, and 13.06 %, respectively.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127791"},"PeriodicalIF":5.8,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004913","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 behaviour of glowing firebrands: Implications for non-reactive surfaces","authors":"Osman Eissa,&nbsp;Maryam Ghodrat","doi":"10.1016/j.ijheatmasstransfer.2025.127788","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127788","url":null,"abstract":"<div><div>Understanding the thermal behaviour of firebrand piles is essential for assessing their energy transfer characteristics and their impact on underlying materials. Due to experimental limitations in capturing spatial thermal distributions within and beneath the pile, as well as the thermal response of individual firebrands within the pile. This study employed a numerical approach to investigate the thermal performance of smouldering firebrand accumulations. The model examined the effects of varying wind speeds (0.9–2.7 m/s) and coverage densities (0.06 and 0.16 g/cm²) on firebrand surface temperature, released heat flux, and heat flux received by the substrate. Model accuracy was verified by comparing its output with the heat release rate per unit area (HRRPUA) derived from an experimental study, ensuring the reliability of the numerical data. Results showed that increased wind speeds and coverage densities significantly increase both average and localized thermal parameters. For smouldering firebrand accumulations, peak average total heat flux to the substrate ranged from 19 to 52 kW/m², while localized regions within the pile reached up to 120 kW/m². These findings demonstrate the importance of spatial thermal analysis in characterizing firebrand pile behaviour.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127788"},"PeriodicalIF":5.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997128","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":"Structural and thermal properties of paraffin-based graphene and carbon fibre composite phase change materials","authors":"Vimukthi Dananjaya ,&nbsp;Xu Bao ,&nbsp;Nethmi Hansika ,&nbsp;Chamil Abeykoon","doi":"10.1016/j.ijheatmasstransfer.2025.127696","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127696","url":null,"abstract":"<div><div>Given the energy crisis, decreasing resources of non-renewable energy, and environmental degradation by hydrocarbon-based energy, novel approaches must be designed. Phase Change Materials (PCM), which absorb and release heat during phase transition, are a suitable choice for battery thermal management systems. However, most pure PCMs possess poor thermal conductivity, limiting practical applications. Enhancing their thermal properties is crucial for effective utilization of them across a wide range of applications. This study focuses on improving PCM’s performance by incorporating carbon-based fillers, such as milled carbon fibres and graphene, into paraffin wax. Composite phase change materials were prepared with carbon filler loadings of 1–5 wt.% and 8 wt.%, 11 wt.%, and 14 wt.%, using methods such as sonication and magnetic stirring. Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) were used to assess their thermal properties. Results showed significant improvements in thermal conductivity and stability with carbon fillers, though bulk heat capacity decreased slightly. Among the tested compositions, the milled carbon fibre-paraffin composite of 5 wt.% exhibited the highest thermal conductivity of 1.448 W m⁻¹ K⁻¹. The degradation temperature of paraffin increased by 10–30 °C with carbon-based fillers, depending on composition. DSC analysis showed phase change peaks between 30–40 °C (solidification) and 50–60 °C (melting), confirming the preservation of paraffin’s thermal properties. Overall, the findings of this study highlight the potential of composite PCMs in enhancing the performance of battery thermal management systems (BTMS), offering a promising avenue for future energy solutions through improved materials that can be promising for thermal management applications.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127696"},"PeriodicalIF":5.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997082","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":"Enhancement on thermal properties of graphene/paraffin phase change microcapsules with connected thermal network","authors":"Zexu Wang ,&nbsp;Tingting Miao ,&nbsp;Yaohui Zhang ,&nbsp;Cheng Chang ,&nbsp;Ruoxin Wang ,&nbsp;Kai Lang ,&nbsp;Fei Wang","doi":"10.1016/j.ijheatmasstransfer.2025.127780","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127780","url":null,"abstract":"<div><div>To address the challenges of paraffin leakage and low thermal conductivity during heat transfer processes, we developed microencapsulated phase change materials (MEPCMs) through an ultrasonic-electrostatic self-assembly strategy. The system features paraffin as the core and graphene nanosheets as a multifunctional shell, with hot-pressing consolidation effectively minimizing interfacial voids and contact resistance. The microstructure and thermal characterization revealed that the graphene shell simultaneously prevents paraffin leakage and establishes a continuous thermal conduction network. With graphene content of 10 wt%, the thermal conductivity of the MEPCMs increased from 0.22 W/(m·K) to 1.86 W/(m·K), accompanied by enhancements of 39.56% and 41.12% in heat storage and exothermic rates, respectively. Additionally, the enthalpy of phase transition of the MEPCMs reached 144.27 J/g. The MEPCMs prepared in this study demonstrated excellent thermal storage capacity and high thermal conductivity, highlighting their potential for applications in thermal energy storage and thermal management.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127780"},"PeriodicalIF":5.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997081","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":"Microscale simulation of water desalination in Direct Contact Membrane Distillation","authors":"Mostafa J. Gildeh,&nbsp;Nishant Bhatta,&nbsp;Hooman V. Tafreshi,&nbsp;Jun Liu","doi":"10.1016/j.ijheatmasstransfer.2025.127751","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127751","url":null,"abstract":"<div><div>Direct Contact Membrane Distillation (DCMD) is a promising desalination technique that can utilize low-grade energy to desalinate water. This study presents a microscale approach to simulate evaporation and condensation inside hydrophobic fibrous membranes. The novelty of the proposed method is that it incorporates the microstructure of the membranes in the calculations and can potentially be used for optimizing membrane’s microstructure. In particular, the model predicts how feed or permeate pressures and temperatures impact the rate of freshwater production. The simulations were conducted in computational domains that mimic the internal geometry of fibrous DCMD membranes in 2-D. The air–water interfaces (AWIs) over the feed and permeate sides of the membrane were simulated using an in-house Pore Morphology Method (PMM) MATLAB code. The resulting wetting and non-wetting phases were then exported to ANSYS using a cell-marking method. The Schrage phase change model was coupled with the ANSYS’s volume of fluid (VOF) solver to simulate water evaporation at the feed AWI and condensation at the permeate AWI. The simulations revealed that increasing the feed or permeate pressure can, to some extent, improve the rate of freshwater production by bringing the feed and permeate AWIs closer to one another and by increasing their surface areas. It was also observed that increasing the feed and permeate temperatures, while keeping their temperature difference constant, can enhance the freshwater production rate significantly.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127751"},"PeriodicalIF":5.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997080","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 flow and heat transfer characteristics of cross-jet impingement cooling","authors":"Sheng-ju Wang ,&nbsp;Qing-guo Lin ,&nbsp;Ting Li ,&nbsp;Ming-yang Tan ,&nbsp;Zhe-hang Shi ,&nbsp;Hai-feng Liu ,&nbsp;Wei-feng Li","doi":"10.1016/j.ijheatmasstransfer.2025.127772","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127772","url":null,"abstract":"<div><div>Parallel-jet impingement cooling is critical for thermal protection in liquid rocket engines due to its high heat flux and uniformity. However, the impact of practical jet misalignment (e.g., from hydraulic flip or installation deviations) on film cooling remains insufficiently understood. This study addresses this research gap by quantifying the effects of jet Reynolds number (<em>Re</em>), spacing (<em>L</em>_N), and cross angle (Φ) on film flow and heat transfer for cross-jet impingement. Key findings reveal that while increasing jet spacing or reducing cross angle expands the film wetted area, the configuration with large cross angle (<em>Φ=</em>60°) disrupts the expected wetted area growth with <em>Re</em> due to fountain sheet dynamics, complicating the achievement of precise control. Crucially, compared to parallel-jet impingement cooling (<em>Φ=</em>0°), cross-jet impingement with <em>Φ=</em>60° significantly enhances the local maximum heat flux and Nusselt number at specific points but markedly reduces overall cooling uniformity. Quantitatively, at identical jet spacing, the maximum heat flux of cross-jet impingement exceeds that of parallel-jet by 2.78 % on average, while the cooling uniformity index is reduced by 13.56 % on average. Through scaling analysis, novel semi-empirical correlations are established to predict the maximum surface heat flux and Nusselt number along the stagnation line, explaining their deviation from local velocity trends under different boiling modes. These findings provide valuable data and a significant reference for optimizing liquid film cooling systems and mitigating catastrophic failures in thermally critical applications.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127772"},"PeriodicalIF":5.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997197","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":"Effect of heat exchange with the environment on phase formation during combustion synthesis of a composite","authors":"Yu A. Chumakov","doi":"10.1016/j.ijheatmasstransfer.2025.127794","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127794","url":null,"abstract":"<div><div>A combustion synthesis model of the composite in the multicomponent powder mixture is proposed. The fraction of reactants and synthesis products changes are described using theory of formal chemical kinetic. The model takes into account the reaction retardation by the synthesized product layer. The influence of heat loss to the environment on phase formation during the combustion synthesis process is analyzed from combustion initiation and to products cooldown. A powder mixture of titanium, aluminum and boron is considered as a model system of the synthesis. The numerical simulation reveals that intensive heat loss to the lower temperature environment leads to a decrease in the fraction of the boride phase and intermetallic phases in the final composite, while the fraction of the initial reagents increases. It was found that synthesis products begin to form in the reaction wave, but the most intense phase formation occurs after the reaction wave reaches the bottom surface of the sample. The calculation results are in agreement with experimental data.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127794"},"PeriodicalIF":5.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997193","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":"Multiscale analysis of heat-mass-reaction coupling in the controlled synthesis of graphene oxide via heart-shaped microchannels","authors":"Yifan Li ,&nbsp;Xiaojun Xiong ,&nbsp;Hongao Yang ,&nbsp;Wei Yu ,&nbsp;Bingyang Cao","doi":"10.1016/j.ijheatmasstransfer.2025.127802","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127802","url":null,"abstract":"<div><div>Precise regulation of the oxidation degree of graphene oxide (GO) is critical for tailoring its physicochemical properties and expanding its applications. In this work, a heart-shaped microchannel was designed to achieve controlled GO synthesis via geometry-induced heat-mass-reaction coupling. A multiscale simulation strategy integrating the Discrete Phase Model (DPM), Discrete Element Method (DEM), and Reactive Molecular Dynamics (RMD) was developed to uncover the underlying mechanism. Increasing the inlet velocity from 0.025 m/s to 1.0 m/s enhanced the maximum shear rate and wall heat flux, accelerating convective heat transfer and mass mixing in the bifurcation and recombination zones. The higher flow velocities induced stronger interparticle and wall contact forces, potentially facilitating graphite fragmentation. Experimental results demonstrated that as the flow velocity decreases (from 1.0 m/s to 0.025 m/s), the O/C ratio decreases from 0.44 to 0.21, showing good agreement with the oxidation trend predicted by the RMD simulations (from 0.43 to 0.28). This study establishes a geometry-guided, multiphysics-multiscale framework for the rational design of microchannel systems for nanomaterial synthesis.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127802"},"PeriodicalIF":5.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997195","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":"Enhanced performance of PEMFC through novel flow field design and optimization","authors":"Ya Xie,&nbsp;Ying Huang,&nbsp;Jing Zeng,&nbsp;Tong Gao,&nbsp;Dongming Ye,&nbsp;Ruiying Chai","doi":"10.1016/j.ijheatmasstransfer.2025.127792","DOIUrl":"10.1016/j.ijheatmasstransfer.2025.127792","url":null,"abstract":"<div><div>The flow field design significantly impacts proton exchange membrane fuel cell (PEMFC) performance. This study introduces a novel expanding-straight-contracting flow field (ESCFF) design, comparing four variants against conventional serpentine and converging-diverging lung-shaped serpentine (CDLIS) configurations. The ESCFF-3 design (contraction ratio: 0.4) demonstrates optimal performance, increasing oxygen molar concentration by 38.60% versus serpentine and 8.25% versus CDLIS, while improving oxygen distribution uniformity by 11.0% and 2.1% respectively. Liquid water saturation is reduced by 16.32% compared to serpentine and 0.91% versus CDLI, with net power enhancements of 23.7% and 2.85%. These improvements stem from ESCFF-3′s rational inlet/outlet arrangement and structural design. Furthermore, response surface methodology (RSM) optimization of operational parameters and gas diffusion layer porosit further enhances performance, achieving a 3.84% increase in net power. The reliability of these results is validated through confidence interval analysis. In conclusion, the ESCFF-3 flow field enhances membrane hydration and liquid water removal capability, thereby significantly improving the output performance of PEMFC.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"255 ","pages":"Article 127792"},"PeriodicalIF":5.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997189","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}