Pub Date : 2026-06-01Epub Date: 2026-01-21DOI: 10.1016/j.ijthermalsci.2026.110711
Shi Tao , Guofei Lin , Hao Wu , Junjie Hu , Qing He
Elastic vortex generators (VGs) have recently emerged as a promising passive technique for enhancing heat transfer in confined flows. This numerical study investigates the flow and thermal characteristics in a heated channel equipped with tandem flexible flags acting as VGs. The velocity and temperature fields are solved using the dual-distribution discrete unified gas kinetic scheme (DUGKS), while fluid-structure-thermal interactions are captured via a non-iterative immersed boundary (IB) method. Focus is placed on heat transfer enhancement via flow-induced vibrations. Key parameters including the Reynolds number , spacing ratio , and length ratio are systematically examined. The results demonstrate that the flapping motion of the flags significantly disrupts the thermal boundary layer, promotes fluid mixing, and enhances convective heat transfer with only a marginal increase in flow resistance. Optimal heat transfer performance is achieved at and , with an overall heat transfer efficiency improvement of up to 24.4 % compared to the unobstructed channel. Enhancement is more pronounced at higher Reynolds numbers, reaching 30 % at = 400. This work highlights the potential of tandem flexible VGs as an effective passive thermal management strategy for compact electronic systems and heat exchangers.
{"title":"Numerical study of flow and heat transfer characteristics in a channel with tandem flexible vortex generators","authors":"Shi Tao , Guofei Lin , Hao Wu , Junjie Hu , Qing He","doi":"10.1016/j.ijthermalsci.2026.110711","DOIUrl":"10.1016/j.ijthermalsci.2026.110711","url":null,"abstract":"<div><div>Elastic vortex generators (VGs) have recently emerged as a promising passive technique for enhancing heat transfer in confined flows. This numerical study investigates the flow and thermal characteristics in a heated channel equipped with tandem flexible flags acting as VGs. The velocity and temperature fields are solved using the dual-distribution discrete unified gas kinetic scheme (DUGKS), while fluid-structure-thermal interactions are captured via a non-iterative immersed boundary (IB) method. Focus is placed on heat transfer enhancement via flow-induced vibrations. Key parameters including the Reynolds number <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>, spacing ratio <span><math><mrow><mi>S</mi><mo>/</mo><mi>H</mi></mrow></math></span>, and length ratio <span><math><mrow><msub><mi>L</mi><mn>0</mn></msub><mo>/</mo><msub><mi>L</mi><mn>1</mn></msub></mrow></math></span> are systematically examined. The results demonstrate that the flapping motion of the flags significantly disrupts the thermal boundary layer, promotes fluid mixing, and enhances convective heat transfer with only a marginal increase in flow resistance. Optimal heat transfer performance is achieved at <span><math><mrow><mi>S</mi><mo>/</mo><mi>H</mi><mo>=</mo><mn>1.5</mn></mrow></math></span> and <span><math><mrow><msub><mi>L</mi><mn>0</mn></msub><mo>/</mo><msub><mi>L</mi><mn>1</mn></msub><mo>=</mo><mn>3</mn><mo>/</mo><mn>4</mn></mrow></math></span>, with an overall heat transfer efficiency improvement of up to 24.4 % compared to the unobstructed channel. Enhancement is more pronounced at higher Reynolds numbers, reaching 30 % at <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span> = 400. This work highlights the potential of tandem flexible VGs as an effective passive thermal management strategy for compact electronic systems and heat exchangers.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110711"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023866","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}
The increasing heat flux in compact electronic devices necessitates advanced cooling solutions that exceed the capabilities of conventional microchannel heat sinks (MCHSs). This study presents a novel design using anisotropic gradient porous fins within MCHSs to achieve superior thermal performance while managing hydraulic penalties. The key innovation involves combining directional permeability anisotropy with graded Darcy numbers (10−1 – 10−4) to enable simultaneous heat transfer enhancement and flow resistance control. Eleven configurations, including a solid-fin baseline and various porous arrangements (uniform, stepwise, and linear gradients), were numerically investigated. The influence of Reynolds number (Re = 100–1000), fin thickness ratio (a1/a3 = 0.167–0.35), and fin height ratio (h2/a3 = 0.3–2.0) on thermohydraulic performance was systematically evaluated under a constant heat flux. Results show that Configuration 5 (stepwise decreasing permeability) achieved a 76.84 % reduction in thermal resistance and a 3594.71 % performance gain over the baseline at Re = 500. Increasing fin thickness from a1/a3 = 0.167 to 0.35 led to a 79.54 % drop in thermal resistance and a 4592.18 % increase in performance metric, while increasing height to h2/a3 = 2.0 resulted in a 5159.31 % improvement. Performance continued to rise with Reynolds number, reaching 4000 % improvement in performance metric at Re = 1000. These findings validate anisotropic gradient porous fins as a transformative approach for next-generation, high-flux thermal management systems.
{"title":"Anisotropic gradient porous fins for microchannel heat sinks: A new paradigm in thermal management design","authors":"Hamid-Reza Bahrami , Amir-Erfan Sharifi , Mahziyar Ghaedi","doi":"10.1016/j.ijthermalsci.2026.110706","DOIUrl":"10.1016/j.ijthermalsci.2026.110706","url":null,"abstract":"<div><div>The increasing heat flux in compact electronic devices necessitates advanced cooling solutions that exceed the capabilities of conventional microchannel heat sinks (MCHSs). This study presents a novel design using anisotropic gradient porous fins within MCHSs to achieve superior thermal performance while managing hydraulic penalties. The key innovation involves combining directional permeability anisotropy with graded Darcy numbers (10<sup>−1</sup> – 10<sup>−4</sup>) to enable simultaneous heat transfer enhancement and flow resistance control. Eleven configurations, including a solid-fin baseline and various porous arrangements (uniform, stepwise, and linear gradients), were numerically investigated. The influence of Reynolds number (Re = 100–1000), fin thickness ratio (a<sub>1</sub>/a<sub>3</sub> = 0.167–0.35), and fin height ratio (h<sub>2</sub>/a<sub>3</sub> = 0.3–2.0) on thermohydraulic performance was systematically evaluated under a constant heat flux. Results show that Configuration 5 (stepwise decreasing permeability) achieved a 76.84 % reduction in thermal resistance and a 3594.71 % performance gain over the baseline at Re = 500. Increasing fin thickness from a<sub>1</sub>/a<sub>3</sub> = 0.167 to 0.35 led to a 79.54 % drop in thermal resistance and a 4592.18 % increase in performance metric, while increasing height to h<sub>2</sub>/a<sub>3</sub> = 2.0 resulted in a 5159.31 % improvement. Performance continued to rise with Reynolds number, reaching 4000 % improvement in performance metric at Re = 1000. These findings validate anisotropic gradient porous fins as a transformative approach for next-generation, high-flux thermal management systems.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110706"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024190","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}
Pub Date : 2026-06-01Epub Date: 2026-01-22DOI: 10.1016/j.ijthermalsci.2026.110714
Zhengchun Li , Jun Huang , Yazhu Zhang , Wenxue Wang , Yonghong Wang , Jing Zeng
Thermal contact conductance (TCC) is a critical parameter in heat transfer with significant implications across numerous technological fields. Its value is influenced by multiple interrelated factors, including the thermo-mechanical properties of the materials, contact pressure, and interface temperature. Accurate prediction of TCC remains challenging and requires a combination of theoretical and experimental approaches. In this study, an experimental system based on the steady-state heat flux method was developed to investigate the TCC at the interface of SAE 1040 steel under high temperatures. Tests were conducted over an interfacial temperature range of 400–800 °C and contact pressures from 0 MPa to 14.0 MPa, systematically examining the effects of temperature, pressure, and surface topography on TCC. Experimental results demonstrate that TCC increases monotonically with both temperature and pressure, with the enhancing effect of pressure being particularly pronounced in the 600–800 °C range. Mechanism analysis reveals that the evolution of material thermo-mechanical properties at elevated temperatures, oxide layer formation dynamics in air, and solid-state phase transformations are the primary influencing factors. Comparison with classical theoretical models shows that the CMY plastic model demonstrates optimal agreement with experimental data in the high-temperature regime (700–800 °C), whereas the Mikic elastic model provides superior predictions in the medium-to-low temperature range (400–600 °C). Moreover, gap conduction contributes significantly to heat transfer in air environments. Based on these insights, this paper proposes a predictive model for TCC applicable in air environments. The model accounts for coupled effects such as solid-spot conduction and gap conductance, addressing the limitations of existing models under high-temperature, high-pressure, and air-exposed conditions.
{"title":"Investigation of high-temperature interfacial thermal contact conductance of SAE 1040 steel based on steady-state heat flux method: Comparing experimental results with theoretical models","authors":"Zhengchun Li , Jun Huang , Yazhu Zhang , Wenxue Wang , Yonghong Wang , Jing Zeng","doi":"10.1016/j.ijthermalsci.2026.110714","DOIUrl":"10.1016/j.ijthermalsci.2026.110714","url":null,"abstract":"<div><div>Thermal contact conductance (TCC) is a critical parameter in heat transfer with significant implications across numerous technological fields. Its value is influenced by multiple interrelated factors, including the thermo-mechanical properties of the materials, contact pressure, and interface temperature. Accurate prediction of TCC remains challenging and requires a combination of theoretical and experimental approaches. In this study, an experimental system based on the steady-state heat flux method was developed to investigate the TCC at the interface of SAE 1040 steel under high temperatures. Tests were conducted over an interfacial temperature range of 400–800 °C and contact pressures from 0 MPa to 14.0 MPa, systematically examining the effects of temperature, pressure, and surface topography on TCC. Experimental results demonstrate that TCC increases monotonically with both temperature and pressure, with the enhancing effect of pressure being particularly pronounced in the 600–800 °C range. Mechanism analysis reveals that the evolution of material thermo-mechanical properties at elevated temperatures, oxide layer formation dynamics in air, and solid-state phase transformations are the primary influencing factors. Comparison with classical theoretical models shows that the CMY plastic model demonstrates optimal agreement with experimental data in the high-temperature regime (700–800 °C), whereas the Mikic elastic model provides superior predictions in the medium-to-low temperature range (400–600 °C). Moreover, gap conduction contributes significantly to heat transfer in air environments. Based on these insights, this paper proposes a predictive model for TCC applicable in air environments. The model accounts for coupled effects such as solid-spot conduction and gap conductance, addressing the limitations of existing models under high-temperature, high-pressure, and air-exposed conditions.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110714"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023753","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}
Pub Date : 2026-06-01Epub Date: 2026-01-21DOI: 10.1016/j.ijthermalsci.2026.110701
Kaiming Li , Yueyang Zhu , Xiang Li , Bingqiang Zhang , Sanzhao Wang , Hui Liu , Hua Cai
The fabrication of large fiber optic panel (FOP) is constrained by hot-pressing-induced fracture and ion-diffusion-induced chromatic aberration, primarily caused by non-uniform heating and prolonged ion diffusion during the vacuum hot-pressing (VHP) process. Numerical simulation provides a promising approach to address these challenges. In this study, a three-zone experimental temperature boundary was introduced to drive the heat source, and both heat conduction and thermal radiation mechanisms were considered to establish, for the first time, a fully coupled FOP–mold–VHP furnace thermal prediction model. Comparative analysis between experimental and simulated data shows that achieving a high level of agreement between computational and measured temperature profiles requires distinct thermal conductivity inputs for FOPs of different sizes. Moreover, reducing the temperature sampling interval significantly improves prediction accuracy, reaching a maximum of 94.33 %. The surface emissivity of the mold is identified as a key parameter influencing the temperature distribution. The proposed model demonstrates strong applicability across molds and FOPs of varying sizes and geometries. For the heating processes of the R mold and G6000 mold, the optimized procedure reduces heating times by 100 and 130 min, respectively, substantially enhancing energy efficiency. By integrating the COMSOL PID control module, the model realistically reproduces furnace PID-controlled heating behavior without the need for developing complex algorithms. This study provides a reliable tool for temperature field prediction in FOP hot-forming processes, offering valuable guidance for the design of large FOP and next-generation VHP furnaces.
{"title":"Coupled thermal modeling and experimental validation in large fiber optic panel vacuum hot-pressing furnace","authors":"Kaiming Li , Yueyang Zhu , Xiang Li , Bingqiang Zhang , Sanzhao Wang , Hui Liu , Hua Cai","doi":"10.1016/j.ijthermalsci.2026.110701","DOIUrl":"10.1016/j.ijthermalsci.2026.110701","url":null,"abstract":"<div><div>The fabrication of large fiber optic panel (FOP) is constrained by hot-pressing-induced fracture and ion-diffusion-induced chromatic aberration, primarily caused by non-uniform heating and prolonged ion diffusion during the vacuum hot-pressing (VHP) process. Numerical simulation provides a promising approach to address these challenges. In this study, a three-zone experimental temperature boundary was introduced to drive the heat source, and both heat conduction and thermal radiation mechanisms were considered to establish, for the first time, a fully coupled FOP–mold–VHP furnace thermal prediction model. Comparative analysis between experimental and simulated data shows that achieving a high level of agreement between computational and measured temperature profiles requires distinct thermal conductivity inputs for FOPs of different sizes. Moreover, reducing the temperature sampling interval significantly improves prediction accuracy, reaching a maximum of 94.33 %. The surface emissivity of the mold is identified as a key parameter influencing the temperature distribution. The proposed model demonstrates strong applicability across molds and FOPs of varying sizes and geometries. For the heating processes of the R mold and G6000 mold, the optimized procedure reduces heating times by 100 and 130 min, respectively, substantially enhancing energy efficiency. By integrating the COMSOL PID control module, the model realistically reproduces furnace PID-controlled heating behavior without the need for developing complex algorithms. This study provides a reliable tool for temperature field prediction in FOP hot-forming processes, offering valuable guidance for the design of large FOP and next-generation VHP furnaces.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110701"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023748","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}
Pub Date : 2026-06-01Epub Date: 2026-01-20DOI: 10.1016/j.ijthermalsci.2026.110709
Fangfang Chen , Pengyue Wu , Xiaohui Wang , Shuichao Kou , Jiewen Wang , Peihao Yang , Xuesong Zhang , Wei Wang , Qie Sun
Hybrid supercapacitor energy storage systems (HSESSs) are critical for renewable energy integration but face significant thermal challenges due to Joule heating during rapid cycling. While multi-inlet cooling strategies have proven effective in battery systems, their application in large-scale HSESS remains underexplored. This study developed and validated an equivalent thermal model of supercapacitors based on experimental data. Using computational fluid dynamics analysis, limitations of conventional thermal management approaches were identified, leading to the proposal of a multi-inlet bidirectional air cooling thermal management system adapted from proven battery technologies. Simulation results indicate that, under an inlet flow rate of 0.15 m3/s and an inlet temperature of 300.15 K, the proposed bidirectional air cooling system reduces the average temperature in the HSESS cabinet by 15.4 K and the temperature standard deviation by 8.4 K, compared to the conventional system. These findings confirm that the bidirectional design significantly enhances cooling efficiency and temperature uniformity, providing an effective solution for system-level HSESS thermal management.
{"title":"Optimization of a bidirectional air cooling thermal management system for hybrid supercapacitor energy storage system (HSESS)","authors":"Fangfang Chen , Pengyue Wu , Xiaohui Wang , Shuichao Kou , Jiewen Wang , Peihao Yang , Xuesong Zhang , Wei Wang , Qie Sun","doi":"10.1016/j.ijthermalsci.2026.110709","DOIUrl":"10.1016/j.ijthermalsci.2026.110709","url":null,"abstract":"<div><div>Hybrid supercapacitor energy storage systems (HSESSs) are critical for renewable energy integration but face significant thermal challenges due to Joule heating during rapid cycling. While multi-inlet cooling strategies have proven effective in battery systems, their application in large-scale HSESS remains underexplored. This study developed and validated an equivalent thermal model of supercapacitors based on experimental data. Using computational fluid dynamics analysis, limitations of conventional thermal management approaches were identified, leading to the proposal of a multi-inlet bidirectional air cooling thermal management system adapted from proven battery technologies. Simulation results indicate that, under an inlet flow rate of 0.15 m<sup>3</sup>/s and an inlet temperature of 300.15 K, the proposed bidirectional air cooling system reduces the average temperature in the HSESS cabinet by 15.4 K and the temperature standard deviation by 8.4 K, compared to the conventional system. These findings confirm that the bidirectional design significantly enhances cooling efficiency and temperature uniformity, providing an effective solution for system-level HSESS thermal management.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110709"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023856","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}
Pub Date : 2026-06-01Epub Date: 2026-01-20DOI: 10.1016/j.ijthermalsci.2026.110702
Qingxu Ma , Yan Wang , Fan Wang , Haohan Sha , Siyi Luo , Chengshan Xu , Hewu Wang , Xilong Zhang
<div><div>In the energy flow analysis of lithium-ion battery(LIB) thermal runaway (TR), the convective heat transfer coefficient (<span><math><mrow><mi>h</mi></mrow></math></span>) serves as a core parameter. However, a critical research gap exists: existing studies lack dynamic characterization of the transient convective heat transfer coefficient during LIB TR, and the correlation mechanism between jet behaviors and energy transfer remains unclear—this constitutes the core scientific problem addressed in this study. The primary research objective is to fill this gap by establishing a dynamic analysis method for energy transfer during TR and revealing the influence of state of charge (SOC) on the coupling relationship between jet characteristics and energy flow. To achieve this, this study developed an experimental platform for LIB TR. Experiments were performed in a sealed environment, during which the surface temperatures of the cathode, anode, and safety valve—along with the temperature and pressure inside the experimental cabin—of a commercial lithium-ion power battery (hereafter referred to as the “battery”) were simultaneously monitored. A gas chromatograph was utilized to conduct quantitative analysis of the gas components produced during TR. Based on the ideal gas state equation, the flow rate of the evolved gas was calculated. The jet process was divided into three stages—laminar flow, transitional flow, and turbulent flow—based on the Reynolds number (<span><math><mrow><msub><mi>R</mi><mi>e</mi></msub></mrow></math></span>). Based on this classification, the Nusselt number (<span><math><mrow><msub><mi>N</mi><mi>u</mi></msub></mrow></math></span>) during the entire jet process was determined using a semi-empirical convective heat transfer correlation. By further incorporating the physical properties of the mixed gas, the dynamic variation of the convective heat transfer coefficient was ultimately quantified, thereby developing a dynamic analysis method for energy transfer during battery TR. Furthermore, this study systematically examined the mechanism by which the state of charge (SOC) influences this process. Results indicate that, using a battery at 75 % SOC as an example, two distinct jet behaviors occur during TR, corresponding to peak battery temperatures of 163.7 °C and 332.3 °C. The explosion indices (<span><math><mrow><msub><mi>K</mi><mrow><mi>s</mi><mi>t</mi></mrow></msub></mrow></math></span>) for these two jets were 2.83 kPa m s<sup>−1</sup> and 15.36 kPa m s<sup>−1</sup>, respectively, with a flammable range between 4.91 % and 35.84 %. During Stage VI of the second jet, the <em>Nu</em> and <em>h</em> reached 389.90 and 1350.78 W m<sup>−2</sup> K<sup>−1</sup>, respectively. Regarding energy distribution, the contribution of convective heat transfer to total energy transfer increased significantly, from 1.24 % in Stage IV to 8.47 % in Stage VI. Finally, this study established a TR risk evaluation system for batteries at differ
在锂离子电池（LIB）热失控（TR）的能量流分析中，对流换热系数h作为核心参数。然而，存在一个关键的研究空白：现有研究缺乏LIB TR过程中瞬态对流换热系数的动态表征，射流行为与能量传递的相关机制尚不清楚，这是本研究解决的核心科学问题。本文的主要研究目标是通过建立TR过程中能量传递的动态分析方法，揭示荷电状态（state of charge， SOC）对射流特性与能量流耦合关系的影响，填补这一空白。为此，本研究开发了LIB TR实验平台，实验在密封环境下进行，同时监测商用锂离子动力电池（以下简称“电池”）的阴极、阳极和安全阀表面温度以及实验舱内的温度和压力。利用气相色谱仪对TR过程中产生的气体组分进行定量分析，根据理想气体状态方程，计算出释放气体的流量。根据雷诺数Re将射流过程分为层流、过渡流和湍流三个阶段。在此基础上，利用半经验对流换热相关法确定了整个射流过程中的努塞尔数（Nu）。通过进一步结合混合气体的物理性质，最终量化了对流换热系数的动态变化，从而建立了电池TR过程中能量传递的动态分析方法，并系统地研究了荷电状态（SOC）对这一过程的影响机制。结果表明，以75% SOC的电池为例，在TR过程中出现了两种不同的射流行为，对应于电池峰值温度163.7°C和332.3°C。两种喷流的爆炸指数（Kst）分别为2.83 kPa m s - 1和15.36 kPa m s - 1，可燃范围为4.91% ~ 35.84%。在第二次喷流的第六阶段，Nu和h分别达到389.90和1350.78 W m−2 K−1。在能量分布上，对流换热对总能量传递的贡献显著增加，从第四阶段的1.24%增加到第六阶段的8.47%。最后，通过综合Re、Nu、h、KLIB和峰值温度等关键参数，建立了不同荷电状态（25%、50%、75%、100%）电池的TR风险评价体系。风险等级为：100% SOC >； 75% SOC > 50% SOC > 25% SOC。本研究对电池TR过程中的能量传递过程进行了动态分析，提出了一种将射流参数与能量流关联起来的方法，为电池安全设计、定量风险评估和制定预防控制策略提供了重要的理论和实验依据。
{"title":"Study on jet hydrodynamic parameters and energy flow analysis of lithium-ion batteries","authors":"Qingxu Ma , Yan Wang , Fan Wang , Haohan Sha , Siyi Luo , Chengshan Xu , Hewu Wang , Xilong Zhang","doi":"10.1016/j.ijthermalsci.2026.110702","DOIUrl":"10.1016/j.ijthermalsci.2026.110702","url":null,"abstract":"<div><div>In the energy flow analysis of lithium-ion battery(LIB) thermal runaway (TR), the convective heat transfer coefficient (<span><math><mrow><mi>h</mi></mrow></math></span>) serves as a core parameter. However, a critical research gap exists: existing studies lack dynamic characterization of the transient convective heat transfer coefficient during LIB TR, and the correlation mechanism between jet behaviors and energy transfer remains unclear—this constitutes the core scientific problem addressed in this study. The primary research objective is to fill this gap by establishing a dynamic analysis method for energy transfer during TR and revealing the influence of state of charge (SOC) on the coupling relationship between jet characteristics and energy flow. To achieve this, this study developed an experimental platform for LIB TR. Experiments were performed in a sealed environment, during which the surface temperatures of the cathode, anode, and safety valve—along with the temperature and pressure inside the experimental cabin—of a commercial lithium-ion power battery (hereafter referred to as the “battery”) were simultaneously monitored. A gas chromatograph was utilized to conduct quantitative analysis of the gas components produced during TR. Based on the ideal gas state equation, the flow rate of the evolved gas was calculated. The jet process was divided into three stages—laminar flow, transitional flow, and turbulent flow—based on the Reynolds number (<span><math><mrow><msub><mi>R</mi><mi>e</mi></msub></mrow></math></span>). Based on this classification, the Nusselt number (<span><math><mrow><msub><mi>N</mi><mi>u</mi></msub></mrow></math></span>) during the entire jet process was determined using a semi-empirical convective heat transfer correlation. By further incorporating the physical properties of the mixed gas, the dynamic variation of the convective heat transfer coefficient was ultimately quantified, thereby developing a dynamic analysis method for energy transfer during battery TR. Furthermore, this study systematically examined the mechanism by which the state of charge (SOC) influences this process. Results indicate that, using a battery at 75 % SOC as an example, two distinct jet behaviors occur during TR, corresponding to peak battery temperatures of 163.7 °C and 332.3 °C. The explosion indices (<span><math><mrow><msub><mi>K</mi><mrow><mi>s</mi><mi>t</mi></mrow></msub></mrow></math></span>) for these two jets were 2.83 kPa m s<sup>−1</sup> and 15.36 kPa m s<sup>−1</sup>, respectively, with a flammable range between 4.91 % and 35.84 %. During Stage VI of the second jet, the <em>Nu</em> and <em>h</em> reached 389.90 and 1350.78 W m<sup>−2</sup> K<sup>−1</sup>, respectively. Regarding energy distribution, the contribution of convective heat transfer to total energy transfer increased significantly, from 1.24 % in Stage IV to 8.47 % in Stage VI. Finally, this study established a TR risk evaluation system for batteries at differ","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110702"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023857","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}
Pub Date : 2026-06-01Epub Date: 2026-01-20DOI: 10.1016/j.ijthermalsci.2026.110704
Zhimin Yao , Yinhui Jiang , Zhihang Yao , Jianxin Yang , Pengcheng Wen , Die Zhao
Microchannel heat exchangers (MCHXs) are valued for their compact structure and high heat-transfer efficiency; however, achieving an optimal balance between heat-transfer enhancement and pressure drop (ΔP) remains a challenge. In this study, a biomimetic shell structure microchannel (BSSM) is proposed to enhance convective heat transfer while moderating flow resistance. A combined experimental–numerical approach is employed to systematically investigate the thermo-hydraulic performance of the BSSM over a Reynolds number range of 200–1200, with particular emphasis on the effects of shell height (Hsh) and radian (αsh). The results demonstrate that the BSSM exhibits markedly superior thermo-hydraulic performance relative to traditional parallel straight microchannels (TPSMs). At Re = 1200, the Nusselt number (Nu) reaches 21.88, representing a 110.78 % enhancement relative to the TPSMs. Increasing the shell height intensifies flow disturbance and heat transfer, but excessive protrusion reduces the effective flow area, leading to localized flow stagnation and a pronounced increase in ΔP. Performance evaluation criterion (PEC) analysis identifies an intermediate shell height (Hsh = 0.3 mm) as optimal. The shell radian is found to exert a strong influence on flow redistribution and heat-transfer intensification, with the optimal configuration exhibiting clear Reynolds-number dependence: the highest PEC is achieved at αsh = 105° for Re = 200–600 and at αsh = 60° for Re = 600–1200. These findings indicate that appropriately scaled shell height and radian enable the most favorable balance between heat-transfer enhancement and flow resistance. From a broader perspective, the present study establishes a quantitative link between biomimetic structural parameters and thermo-hydraulic performance, thereby deepening the physical understanding and design methodology of biomimetic enhanced microchannels. Moreover, the proposed biomimetic shell microchannel offers a geometry-driven and extensible design framework, with strong potential for further optimization and application in compact, high-performance thermal management systems.
{"title":"Investigation of heat and flow transfer characteristics in microchannels of biomimetic shell structures","authors":"Zhimin Yao , Yinhui Jiang , Zhihang Yao , Jianxin Yang , Pengcheng Wen , Die Zhao","doi":"10.1016/j.ijthermalsci.2026.110704","DOIUrl":"10.1016/j.ijthermalsci.2026.110704","url":null,"abstract":"<div><div>Microchannel heat exchangers (MCHXs) are valued for their compact structure and high heat-transfer efficiency; however, achieving an optimal balance between heat-transfer enhancement and pressure drop (<em>ΔP</em>) remains a challenge. In this study, a biomimetic shell structure microchannel (BSSM) is proposed to enhance convective heat transfer while moderating flow resistance. A combined experimental–numerical approach is employed to systematically investigate the thermo-hydraulic performance of the BSSM over a Reynolds number range of 200–1200, with particular emphasis on the effects of shell height (<em>H</em><sub><em>sh</em></sub>) and radian (<em>α</em><sub><em>sh</em></sub>). The results demonstrate that the BSSM exhibits markedly superior thermo-hydraulic performance relative to traditional parallel straight microchannels (TPSMs). At <em>Re</em> = 1200, the Nusselt number (<em>Nu</em>) reaches 21.88, representing a 110.78 % enhancement relative to the TPSMs. Increasing the shell height intensifies flow disturbance and heat transfer, but excessive protrusion reduces the effective flow area, leading to localized flow stagnation and a pronounced increase in <em>ΔP</em>. Performance evaluation criterion (<em>PEC</em>) analysis identifies an intermediate shell height (<em>H</em><sub><em>sh</em></sub> = 0.3 mm) as optimal. The shell radian is found to exert a strong influence on flow redistribution and heat-transfer intensification, with the optimal configuration exhibiting clear Reynolds-number dependence: the highest <em>PEC</em> is achieved at <em>α</em><sub><em>sh</em></sub> = 105° for <em>Re</em> = 200–600 and at <em>α</em><sub><em>sh</em></sub> = 60° for <em>Re</em> = 600–1200. These findings indicate that appropriately scaled shell height and radian enable the most favorable balance between heat-transfer enhancement and flow resistance. From a broader perspective, the present study establishes a quantitative link between biomimetic structural parameters and thermo-hydraulic performance, thereby deepening the physical understanding and design methodology of biomimetic enhanced microchannels. Moreover, the proposed biomimetic shell microchannel offers a geometry-driven and extensible design framework, with strong potential for further optimization and application in compact, high-performance thermal management systems.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110704"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023858","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}
Pub Date : 2026-06-01Epub Date: 2026-01-27DOI: 10.1016/j.ijthermalsci.2026.110708
Zenan Yang, Yongjie Li, Chengke Li, Haiwei Yang, Ge Wang
The present study presents a numerical investigation into the heat transfer deterioration (HTD) mechanism during supercritical CO2 flowing upward in a vertical tube, with emphasis on the synergistic role of drastic variations in density and thermal conductivity near the pseudo-critical point. By selectively isolating property variations, the study reveals that abrupt density changes are a primary trigger of HTD, provoking buoyancy-induced flow re-laminarization and flow acceleration that suppress turbulent transport. Furthermore, sharp declines in thermal conductivity are shown to exacerbate HTD through a dual mechanism, that is, impairing heat conduction within the viscous sublayer and intensifying axial thermal gradients, which further amplify buoyancy and acceleration effects. These interactions collectively impair turbulent heat transfer efficiency. The results offer novel understanding of the coupled thermophysical pathways governing HTD and support the optimized design of heat exchange systems in supercritical CO2 power cycles.
{"title":"Numerical study on the effects of drastic variations in thermal conductivity on the supercritical CO2 heat transfer deterioration","authors":"Zenan Yang, Yongjie Li, Chengke Li, Haiwei Yang, Ge Wang","doi":"10.1016/j.ijthermalsci.2026.110708","DOIUrl":"10.1016/j.ijthermalsci.2026.110708","url":null,"abstract":"<div><div>The present study presents a numerical investigation into the heat transfer deterioration (HTD) mechanism during supercritical CO<sub>2</sub> flowing upward in a vertical tube, with emphasis on the synergistic role of drastic variations in density and thermal conductivity near the pseudo-critical point. By selectively isolating property variations, the study reveals that abrupt density changes are a primary trigger of HTD, provoking buoyancy-induced flow re-laminarization and flow acceleration that suppress turbulent transport. Furthermore, sharp declines in thermal conductivity are shown to exacerbate HTD through a dual mechanism, that is, impairing heat conduction within the viscous sublayer and intensifying axial thermal gradients, which further amplify buoyancy and acceleration effects. These interactions collectively impair turbulent heat transfer efficiency. The results offer novel understanding of the coupled thermophysical pathways governing HTD and support the optimized design of heat exchange systems in supercritical CO<sub>2</sub> power cycles.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110708"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074545","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}
Pub Date : 2026-06-01Epub Date: 2026-01-30DOI: 10.1016/j.ijthermalsci.2026.110736
Fatih Selimefendigil , Hakan F. Oztop
Heating of an annular plate (AN-PL) in a ventilated trapezoidal enclosure is studied under magnetic field effects. A thermal buffer is obtained in the inner part of the AN-PL by using phase change material (PCM). Finite element based simulation of the coupled system is performed while impacts of flow Reynolds number (Re), inlet temperature of hot liquid and magnetic field parameters on the temperature rise of the plate, and melting time () are explored. The time at which the PCM’s effect on AN-PL temperature enhancement becomes effective is indicated by the critical time (). The values of and drop by around 37.8% and 33.3% at the maximum Re. At the lowest Re case, PCM results in an AN-PL temperature increase of 3.1 °C in comparison to the case without PCM. Magnetic field parameters are effective in the flow distributions near the inlet port, but they have a very small effect on the heating of AN-PL. In contrast to the reference scenario without PCM and the lowest inlet temperature, PCM produces the largest heating of the AN-PL at the highest Re and inlet temperature, resulting in a higher plate temperature of 21.2 °C. When AN-PL is exposed to forced convection of hot liquid in a ventilated enclosure, PCM is shown to be a very effective passive thermal management technique. A variety of industrial applications, such as material processing, process heating, drying applications, and heat exchangers, may utilize the results.
{"title":"Heating of an annular plate under the effects of thermal buffer with phase change material in a trapezoidal vented cavity under convection of hot liquid with magnetic field","authors":"Fatih Selimefendigil , Hakan F. Oztop","doi":"10.1016/j.ijthermalsci.2026.110736","DOIUrl":"10.1016/j.ijthermalsci.2026.110736","url":null,"abstract":"<div><div>Heating of an annular plate (AN-PL) in a ventilated trapezoidal enclosure is studied under magnetic field effects. A thermal buffer is obtained in the inner part of the AN-PL by using phase change material (PCM). Finite element based simulation of the coupled system is performed while impacts of flow Reynolds number (Re), inlet temperature of hot liquid and magnetic field parameters on the temperature rise of the plate, and melting time (<span><math><msub><mrow><mi>t</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span>) are explored. The time at which the PCM’s effect on AN-PL temperature enhancement becomes effective is indicated by the critical time (<span><math><msub><mrow><mi>t</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>). The values of <span><math><msub><mrow><mi>t</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>t</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span> drop by around 37.8% and 33.3% at the maximum Re. At the lowest Re case, PCM results in an AN-PL temperature increase of 3.1 °C in comparison to the case without PCM. Magnetic field parameters are effective in the flow distributions near the inlet port, but they have a very small effect on the heating of AN-PL. In contrast to the reference scenario without PCM and the lowest inlet temperature, PCM produces the largest heating of the AN-PL at the highest Re and inlet temperature, resulting in a higher plate temperature of 21.2 °C. When AN-PL is exposed to forced convection of hot liquid in a ventilated enclosure, PCM is shown to be a very effective passive thermal management technique. A variety of industrial applications, such as material processing, process heating, drying applications, and heat exchangers, may utilize the results.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110736"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074472","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}
Pub Date : 2026-06-01Epub Date: 2026-01-09DOI: 10.1016/j.ijthermalsci.2026.110678
Tianxiang Yan , Muchun Lan , Huiqing Chen , Hucheng Chen
With the improvement of electronic device integration, the heat generated by electronic chips is greatly increasing. To meet the growing cooling demands of electronic chips and enhance the cooling performance of minichannel system, a cooling system integrating an annular valve piezoelectric pump (AVPP) and a leaf-vein minichannel heat sink (LMHS) is proposed. The AVPP with high flow rate and simple valve structure is used to drive the flow of coolant, and the LMHS with excellent heat transfer characteristics is responsible for removing the heat generated by the chip. The LMHS is designed inspired by the structural characteristics of leaf veins and compared with the three-branch minichannel heat sink (TMHS) and serpentine minichannel heat sink (SMHS). The performance of the LMHS, TMHS, and SMHS cooling systems driven by the AVPP is investigated through experiments and simulations. The results indicate that the LMHS cooling system has the better fluid transfer and cooling performance than the TMHS and SMHS cooling systems. When the driving voltage is 300 Vpp, the LMHS cooling system exhibits a high maximum flow rate of 91.85 g/min and a low maximum pressure drop of the heat sink. When the chip power is 30 W, the LMHS cooling system can stabilize the chip temperature at a low temperature of 55.9 °C and reach a high cooling efficiency of 64.2 %. The proposed cooling system has great potential in efficient thermal management of miniaturized electronic chips.
{"title":"Experimental study of a leaf-vein minichannel cooling system driven by piezoelectric pump","authors":"Tianxiang Yan , Muchun Lan , Huiqing Chen , Hucheng Chen","doi":"10.1016/j.ijthermalsci.2026.110678","DOIUrl":"10.1016/j.ijthermalsci.2026.110678","url":null,"abstract":"<div><div>With the improvement of electronic device integration, the heat generated by electronic chips is greatly increasing. To meet the growing cooling demands of electronic chips and enhance the cooling performance of minichannel system, a cooling system integrating an annular valve piezoelectric pump (AVPP) and a leaf-vein minichannel heat sink (LMHS) is proposed. The AVPP with high flow rate and simple valve structure is used to drive the flow of coolant, and the LMHS with excellent heat transfer characteristics is responsible for removing the heat generated by the chip. The LMHS is designed inspired by the structural characteristics of leaf veins and compared with the three-branch minichannel heat sink (TMHS) and serpentine minichannel heat sink (SMHS). The performance of the LMHS, TMHS, and SMHS cooling systems driven by the AVPP is investigated through experiments and simulations. The results indicate that the LMHS cooling system has the better fluid transfer and cooling performance than the TMHS and SMHS cooling systems. When the driving voltage is 300 V<sub>pp</sub>, the LMHS cooling system exhibits a high maximum flow rate of 91.85 g/min and a low maximum pressure drop of the heat sink. When the chip power is 30 W, the LMHS cooling system can stabilize the chip temperature at a low temperature of 55.9 °C and reach a high cooling efficiency of 64.2 %. The proposed cooling system has great potential in efficient thermal management of miniaturized electronic chips.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"224 ","pages":"Article 110678"},"PeriodicalIF":5.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923841","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}
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