International Journal of Thermal Sciences最新文献

{"title":"Fluid-thermal coupling simulation based on a multi-evaporator loop heat pipe with gas-coupled pipelines","authors":"Depu Lu ,&nbsp;Rui Zhang ,&nbsp;Errui Ma ,&nbsp;Liyan Ben","doi":"10.1016/j.ijthermalsci.2025.110353","DOIUrl":"10.1016/j.ijthermalsci.2025.110353","url":null,"abstract":"<div><div>A multi-evaporator loop heat pipe (MeLHP) is a kind of special-shaped loop heat pipe (LHP) for specific heat transfer scenarios, such as multiple discrete heat sources and large area heat sources. It often utilises the gas coupling method with parallel pipelines to enable the centralised heat dissipation of multiple heat sources to a single heat sink. Not only inherits the flexible, long-distance and efficient heat transfer characteristics of the normal LHP, a MeLHP further exhibits special characteristics caused by pipeline layout and flow distribution due to its special structure. Based on the theory of flow resistance network and thermal resistance network, a MeLHP shunt model is proposed to describe the coupled relationship of fluid heat transfer between the submodules in the MeLHP. The model can calculate the temperature and pressure distribution of the prototype in steady operation. Validation against prototype experiments shows that the model can estimate evaporator wall temperature with a mean residual error of 0.7 %, with all predicted values falling within ±5 %. It also provided a theoretical support for the anisotropic heat sharing characteristics under different heating power distributions. Each case converges within 50s benefit from the employing of the nodal network method, representing a substantial improvement in efficiency compared with traditional CFD tools. Based on the function of performance prediction, the model can be extended to MeLHPs with similar topologies, thereby supporting the future system-level thermal design.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110353"},"PeriodicalIF":5.0,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263305","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 thermal dynamics and local dry region evolution during shallow water laser welding","authors":"Wenchao Ke ,&nbsp;Yuan Liu ,&nbsp;Fissha Biruke Teshome","doi":"10.1016/j.ijthermalsci.2025.110359","DOIUrl":"10.1016/j.ijthermalsci.2025.110359","url":null,"abstract":"<div><div>Shallow water laser welding (SWLW), a process in the critical transition regime between dry and deep-water techniques, offers significant potential for high-precision joining and cladding in thin water layers. However, the complex multiphysics governing this process, particularly the thermal dynamics and evolution mechanism of the local dry region (LDR), remain poorly understood. In this study, a 3D computational fluid dynamics (CFD) model is proposed to predict the SWLW process of 304 stainless steel at water depths ≤4 mm. The results reveal that the LDR provides an effective thermal shield for SWLW to achieve deep penetration welding similar to that of the conventional laser welding (CLW) case. The LDR boundaries simultaneously serve as sites for intense phase-change-driven heat transfer, which dominates the thermal balance of the process. Furthermore, the LDR is identified as a thermal buffer zone, creating a sharp and discontinuous drop in thermal gradients at its interface with the surrounding water. It demonstrates that increasing the water depth from 2 mm to 4 mm results in a 20.8 % reduction in the LDR's area, a direct consequence of the delicate thermal-hydrodynamic balance governing the process. The findings provide a fundamental understanding of the laser-water/metal interactions, which is significant for optimizing any laser-based process conducted in the presence of thin liquid layers.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110359"},"PeriodicalIF":5.0,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227289","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":"Enhancing thermal management of GaN transistors with direct oil jet impingement: Experimental insights for high-power electronics","authors":"Anas El amraoui ,&nbsp;Riadh Boubaker ,&nbsp;Souad Harmand","doi":"10.1016/j.ijthermalsci.2025.110364","DOIUrl":"10.1016/j.ijthermalsci.2025.110364","url":null,"abstract":"<div><div>This study experimentally investigates the cooling performance of oil jet impingement on high-power GaN transistors, focusing on the effects of nozzle geometry (diameter: 0.5 mm, 1 mm; nozzle-transistor distance: 5 mm, 10 mm) and properties of two fluids (a NewOil-A and Siloil M40). At a flow rate of 80 mL/min, Siloil M40 achieved a heat transfer coefficient of 13 848 W/m²K, reducing junction temperatures to 120 °C under 38 W power dissipation (corresponding to a heat flux density of 135 W/cm²). In contrast, NewOil-A yielded a junction temperature of 90 °C under identical power and heat flux conditions, demonstrating NewOil-A's superior cooling performance. The optimized system enabled a 198 % improvement in power handling compared to uncooled operation. Smaller nozzles (diameter: 0.5 mm) and reduced nozzle-transistor distance (5 mm) enhanced cooling efficiency. Additionally, a novel correlation linking Nusselt, Reynolds, and Prandtl numbers is proposed, offering practical design guidelines for GaN-based power electronics in applications like electric vehicles.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110364"},"PeriodicalIF":5.0,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217564","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":"Investigation on ablation behavior of carbon composites using coupled thermo-chemical peridynamic model","authors":"Dewei He,&nbsp;Dan Huang","doi":"10.1016/j.ijthermalsci.2025.110358","DOIUrl":"10.1016/j.ijthermalsci.2025.110358","url":null,"abstract":"<div><div>This study aims to develop a thermo-chemical coupled model under non-local peridynamic framework to describe the ablation behaviors. The model is derived from the free energy density function that incorporates chemical energy and internal energy description and will be solved in integral form. Based on the proposed coupling model, a comprehensive ablation model for typical thermal protection materials is established, considering the processes including exothermic combustion, endothermic sublimation, and oxygen diffusion. By comparing simulation results with different coupling terms, we achieved surface temperature and ablation rate results that are closer to experimental data, validating the capability of the proposed model of describing the competition mechanism between reaction and diffusion during the ablation process. Furthermore, the ablation process of carbon composites was simplified and simulated, capturing ablation morphology similar to experimental results and exploring the influence of varying ablation rates on the morphology.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110358"},"PeriodicalIF":5.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217563","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":"Influence of anisotropic thermal conductivity on leading edge cooling performance of a film cooled CMC turbine vane","authors":"Jieling Li ,&nbsp;Zhaoguang Wang ,&nbsp;Hongmei Jiang ,&nbsp;Shaopeng Lu ,&nbsp;Chen Zhou","doi":"10.1016/j.ijthermalsci.2025.110360","DOIUrl":"10.1016/j.ijthermalsci.2025.110360","url":null,"abstract":"<div><div>Application of Ceramic matrix composites (CMCs) in high-pressure turbine vane designs have gained increasing attention due to their superior thermal-mechanical performance. The present study investigates the impact of thermal conductivity anisotropy on the cooling performance of a film cooled CMC turbine vane at the leading edge. Based on a typical streamwise lay-up fabrication structure, four anisotropic thermal conductivity configurations of CMCs are implemented to represent individual variations along the thickness-wise, streamwise and spanwise directions. Influences on the overall cooling effectiveness and on the separate cooling schemes of hole channel cooling, external film cooling and internal plenum cooling are analysed. The relative contribution by each cooling scheme under different thermal conductivity configurations is discussed, and the effect of blowing ratio is also examined. Results show the dominant contributor of the overall cooling effectiveness transitions from the hole cooling at upstream regions to the film cooling at downstream. For the anisotropic behaviour, the hole cooling is sensitive to the thickness-wise and streamwise thermal conductivities, the film cooling is responsive to the thickness-wise and spanwise conductivities, and the plenum cooling is only marginally affected by the thickness-wise conductivity. Both the magnitude and the uniformity of the overall cooling effectiveness exhibit the highest dependence on the thickness-wise thermal conductivity. While the relative significance of each cooling scheme remains unchanged under different blowing ratios, the effect of the CMC anisotropy on the cooling performance is enhanced at a higher blowing ratio.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110360"},"PeriodicalIF":5.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217562","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":"Revealing internal flow behavior in adjustable-ring-mode laser welding of titanium alloys with a narrow gap structure","authors":"Shuwen Huang ,&nbsp;Jianfeng Wang ,&nbsp;Zhenmu Xu ,&nbsp;Yuhang Duan ,&nbsp;Xing Liu ,&nbsp;Xiaohong Zhan","doi":"10.1016/j.ijthermalsci.2025.110354","DOIUrl":"10.1016/j.ijthermalsci.2025.110354","url":null,"abstract":"<div><div>Adjustable-ring-mode laser welding (ARMLW) combining both a ring beam and a central Gaussian beam has shown good advantages and feasibility in manufacturing narrow-gap high-performance components. However, the flow dynamics within the molten pool of ARMLW remain unclear. This study investigated thermal characteristics and flow dynamics in ARMLW of Ti-6Al-4V with narrow-gap structure, carrying out experiment and simulation. The results demonstrated that the ARM laser expanded effective heat source distribution, thereby enhancing molten metal flow and sidewall fusion. With the increase of ring-core ratio, the fusion zone at the sidewall gradually enlarged, and the concave angle of molten pool surface profile was increased from 0.87° to 1.31°. However, the flow velocities at both the surface and cross-sectional regions of the molten pool exhibited a non-monotonic trend. The maximum surface velocity of 3.941 m/s and mid-pool velocity of 0.108 m/s were obtained at a ring-core ratio of 1.29, where the fluid flow capacity in the inner sidewall fusion zone was significantly enhanced.Phenomenon above resulted from the peripheral circulation flow induced by the ring laser beam around molten pool, which significantly modified the hydrodynamic behavior of the liquid metal within the fusion zone. This study is anticipated to advance understanding of the phenomena involved in the ARMLW of titanium alloys with narrow gap structure, and further establish a fundamental basis for optimizing the narrow gap laser welding process.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110354"},"PeriodicalIF":5.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217565","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":"Effects of vibration frequency on random stacking and heat transfer traits in a packed bed","authors":"Zhihao Hu,&nbsp;Peng Sun,&nbsp;Tengfei Gao,&nbsp;Yujiao Gui,&nbsp;Ziqi Mu,&nbsp;Zhongliang Zhang,&nbsp;Bin Zheng","doi":"10.1016/j.ijthermalsci.2025.110346","DOIUrl":"10.1016/j.ijthermalsci.2025.110346","url":null,"abstract":"<div><div>To obtain the effect of vibration frequency on the random stacking characteristics and contact heat transfer characteristics of a heat storage particle pile, the random stacking and heat transfer model of heat storage particle piles in particle heat storage tanks was established. 0–25 Hz was selected as the parameter of vibration frequency for investigation. The results showed that the particle packing rate and specific contact number after vibration increased by 7 % and 7.6 %, respectively, compared with those of the particle pile before vibration. The maximum increase in the local packing rate is 21.7 %, which was observed near the heat transfer wall. The average coordination number is maximized to 4.07, and the particle coordination number dispersion is more concentrated. The condition of 5 Hz showed the best random stacking and heat transfer traits.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110346"},"PeriodicalIF":5.0,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217567","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":"An optimization study considering MNP temporal evolution improves therapeutic efficacy in hyperthermia treatment","authors":"Buchen Wu ,&nbsp;Qian Jiang ,&nbsp;Zhaokun Wang ,&nbsp;Chenglei Wang ,&nbsp;Feng Ren ,&nbsp;Hui Tang","doi":"10.1016/j.ijthermalsci.2025.110319","DOIUrl":"10.1016/j.ijthermalsci.2025.110319","url":null,"abstract":"<div><div>This work investigates optimal strategies for achieving the most effective tumor ablation outcomes in magnetic hyperthermia by incorporating the thermal exposure time, magnetic nanoparticle (MNP) dose, injection sites, and waiting time before alternating magnetic field (AMF) application. The optimization framework highlights the significance of thermal exposure time, as this treatment duration substantially influences the temporary distribution of the heat source, i.e., MNPs, and consequently affects the thermal dose for efficacy evaluation. Multi-site MNP injections are involved in both circular and elliptical tumor configurations, and a transversal blood vessel introduces asymmetric cooling effects. This optimization framework can achieve efficient convergence, demonstrating its effectiveness in identifying the optimal strategy. Without the influence of the blood vessel, optimal injections exhibit a centrosymmetric distribution in the circular tumor model; comparatively, a linear distribution along the major axis with approximately halved treatment duration is observed in the elliptical model. When the blood vessel is nearby, the notable asymmetric cooling effects complicate treatment, where the random search method is more effective. Increasing the tumor–vessel distance enhances tumor ablation, reduces MNP dosage and treatment time, and decreases the average injection site deviation; however, the impact becomes marginal at larger distances. This optimization study facilitates the efficacy of practical treatment.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110319"},"PeriodicalIF":5.0,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217566","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":"Molecular dynamics of interfacial heat transfer in metal/non-metal nanofluids on Cu-graphene composite porous substrates","authors":"Nian Xu ,&nbsp;Zilong Liu ,&nbsp;Qian Xu ,&nbsp;Yueqi Zhu ,&nbsp;Dong Wang ,&nbsp;Huaqiang Chu","doi":"10.1016/j.ijthermalsci.2025.110345","DOIUrl":"10.1016/j.ijthermalsci.2025.110345","url":null,"abstract":"<div><div>Addressing the thermal management bottleneck in advanced chip technologies requires a fundamental understanding of phase-change phenomena. This study employs molecular dynamics simulations to systematically investigate the phase-change heat transfer regulation mechanisms in porous graphene-nanofluid composite systems, with a focused comparative analysis on the distinct dynamic behaviors between non-metallic nanofluids (graphene-based) and metallic nanofluids (copper-based) during heating-phase boiling and cooling-phase condensation. By establishing a Cu-graphene composite porous substrate integrated with both nanofluid types, we demonstrate that pore confinement significantly optimizes nucleation dynamics. Graphene-lined pore configurations (Nx-in) accelerate nucleation initiation by 64.7 % compared to a flat structure. Additionally, graphene nanofluids reduce nucleation barriers through nanosheet-induced microvortices. This synergy results in a heat transfer efficiency of 66.28%, which is 6.2 % higher than that of the bare copper substrate. In contrast, copper nanofluids exhibit localized thermal resistance due to nanoparticle agglomeration. During cooling, graphene nanosheets form suspended droplets with a diameter of approximately 50 Å, acting as condensation nuclei. Meanwhile, copper agglomerates immobilize over 80 % of the liquid phase near the wall, reducing thermal dissipation efficiency. Thermal flux orientation governs phase transition modes: axial temperature gradients in Nx-in configurations promote longitudinal fluid fragmentation, whereas restricted lateral heat dissipation in Nx-out systems triggers multicentric fragmentation. The study further reveals interfacial processes as dominant factors in nonequilibrium heat transfer, with graphene nanofluids synergistically enhancing substrate wettability and evaporation kinetics. These findings provide an atomic-scale theoretical framework for material selection (metal/non-metal nanofluid compatibility) and structural optimization in high-power chip thermal management and condenser design.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110345"},"PeriodicalIF":5.0,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217461","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":"Simultaneous measurement of thermal conductivity and diffusivity of microscale films using lock-in thermography","authors":"Yanhui Zhang ,&nbsp;Qinmeng Jiang ,&nbsp;Jie Yang ,&nbsp;Maochao Lv ,&nbsp;Qinyi Li ,&nbsp;Dazhi Hou ,&nbsp;Jianli Wang","doi":"10.1016/j.ijthermalsci.2025.110357","DOIUrl":"10.1016/j.ijthermalsci.2025.110357","url":null,"abstract":"<div><div>The optimal design of thermal management materials depends on comprehensive thermal property data to improve the accuracy of predictive models. However, the accurate and rapid characterization in these materials remains a significant challenge. To address this challenge, a lock-in thermography (LIT) technique is developed to characterize the thermophysical properties of thin films. A modulated laser beam with adjustable power was focused onto the sample surface to induce periodic heating, while the sample was placed in a vacuum chamber to minimize convective heat loss. The resulting temperature distribution on the back surface was captured by an infrared camera and processed using a lock-in module to extract the mapping of the phase lag and the amplitude. The anisotropic thermal diffusivity of the sample film was determined from the spatial distribution of the phase lag using a sub-region fitting method. The anisotropic thermal conductivity and volumetric heat capacity were calculated by analyzing the linear relationship between the amplitude and the laser power. The laser transmission loss rate was calibrated using a standard SUS304 stainless-steel film, and the maximum relative uncertainty of the method was found to be less than 4.9 %. The method was applied to isotropic aluminum films and anisotropic paper films, demonstrating the effectiveness and applicability of this point-source-based LIT approach for characterizing a wide range of materials in thermal science.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"220 ","pages":"Article 110357"},"PeriodicalIF":5.0,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217570","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}