Pub Date : 2026-03-01Epub Date: 2025-12-19DOI: 10.1016/j.ijheatfluidflow.2025.110213
Juhui Chen , Shuxiang Pang , Dan Li , Liwei Chen , Michael Zhurakov , Siarhei Lapatsin , Wenrui Jiang
Conventional microchannels typically exhibit limited heat transfer efficiency and suboptimal flow characteristics. This study investigates two fin-enhanced microchannel geometries, triangular ribbed and corrugated, using a moving-grid method to simulate periodic fin motion. Numerical simulations were conducted over a Reynolds number range of 50–250 at a fin oscillation frequency of 20 Hz. The results show that the triangular ribbed microchannel offers lower flow resistance and improved overall flowability due to its relatively smoother flow path, whereas the corrugated design produces stronger flow disturbances and secondary vortices, leading to enhanced heat transfer, especially at lower Reynolds numbers. However, the intensified flow mixing in the corrugated microchannel also increases flow-path tortuosity, resulting in a larger pressure drop. To evaluate the overall performance, the Performance Evaluation Criterion (PEC) was used. The triangular ribbed channel achieved a maximum PEC of 1.52 at Re = 200, indicating a balanced improvement in both heat transfer and flow resistance. These geometries are relevant for practical thermal management applications, such as compact heat sinks and miniaturized cooling devices, due to their manufacturability and effectiveness in enhancing thermo-fluidic performance.
{"title":"Effect of fin-enhanced microchannel structures on flow and heat transfer: comparison of triangular ribbed and corrugated designs","authors":"Juhui Chen , Shuxiang Pang , Dan Li , Liwei Chen , Michael Zhurakov , Siarhei Lapatsin , Wenrui Jiang","doi":"10.1016/j.ijheatfluidflow.2025.110213","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110213","url":null,"abstract":"<div><div>Conventional microchannels typically exhibit limited heat transfer efficiency and suboptimal flow characteristics. This study investigates two fin-enhanced microchannel geometries, triangular ribbed and corrugated, using a moving-grid method to simulate periodic fin motion. Numerical simulations were conducted over a Reynolds number range of 50–250 at a fin oscillation frequency of 20 Hz. The results show that the triangular ribbed microchannel offers lower flow resistance and improved overall flowability due to its relatively smoother flow path, whereas the corrugated design produces stronger flow disturbances and secondary vortices, leading to enhanced heat transfer, especially at lower Reynolds numbers. However, the intensified flow mixing in the corrugated microchannel also increases flow-path tortuosity, resulting in a larger pressure drop. To evaluate the overall performance, the Performance Evaluation Criterion (<em>PEC</em>) was used. The triangular ribbed channel achieved a maximum <em>PEC</em> of 1.52 at <em>Re</em> = 200, indicating a balanced improvement in both heat transfer and flow resistance. These geometries are relevant for practical thermal management applications, such as compact heat sinks and miniaturized cooling devices, due to their manufacturability and effectiveness in enhancing thermo-fluidic performance.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110213"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cooling and thermal management in micro-scale systems are critically important in various applications, as they minimize equipment size and extend its lifespan. Although conventional solid-fin heat sinks have boosted the efficiency of cooling systems, they face a fundamental trade-off between heat dissipation efficiency, energy consumption, and the mechanical power required for pumping. To overcome this, porous fins are applicable; however, their performance is often limited by low effective thermal conductivity and a lack of geometric design refinement. Therefore, this study introduces a novel hybrid porous-solid fin design that strategically combines the high conductivity of solid fins with the superior surface area and flow mixing of porous materials. This numerical investigation analyzes the thermal–hydraulic performance of the hybrid microchannel, focusing on the effects of porous layer thickness (tp), height (hp), Reynolds number (Re), and porosity (ε). Simulations identify that a porous thickness of tp = 0.3 mm yields the best performance, which reduces pressure drop by 21.96 % while simultaneously enhancing heat transfer by 31.21 %, culminating in a 42.51 % improvement in the Performance Evaluation Factor (PEF) compared to conventional solid fins. The analysis further reveals that increasing Re decreases thermal resistance at the expense of a higher pressure drop, while lower porosity enhances heat transfer at the cost of increased flow resistance. Crucially, the favorable porous height for PEF decreases with higher Re, emphasizing the necessity for a flow-condition-specific design to maximize the benefits of this hybrid approach.
{"title":"Parametric investigation of a solid-porous fin design for microchannel thermal performance improvement","authors":"Hanieh Asgharpouri Moghadam , Farid Dolati , Fatemeh Bagherighajari , Morteza Momeni Taromsari","doi":"10.1016/j.ijheatfluidflow.2025.110210","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110210","url":null,"abstract":"<div><div>Cooling and thermal management in micro-scale systems are critically important in various applications, as they minimize equipment size and extend its lifespan. Although conventional solid-fin heat sinks have boosted the efficiency of cooling systems, they face a fundamental trade-off between heat dissipation efficiency, energy consumption, and the mechanical power required for pumping. To overcome this, porous fins are applicable; however, their performance is often limited by low effective thermal conductivity and a lack of geometric design refinement. Therefore, this study introduces a novel hybrid porous-solid fin design that strategically combines the high conductivity of solid fins with the superior surface area and flow mixing of porous materials. This numerical investigation analyzes the thermal–hydraulic performance of the hybrid microchannel, focusing on the effects of porous layer thickness (<em>t<sub>p</sub></em>), height (<em>h<sub>p</sub></em>), Reynolds number (<em>Re</em>), and porosity (<em>ε</em>). Simulations identify that a porous thickness of <em>t<sub>p</sub></em> = 0.3 mm yields the best performance, which reduces pressure drop by 21.96 % while simultaneously enhancing heat transfer by 31.21 %, culminating in a 42.51 % improvement in the Performance Evaluation Factor (<em>PEF</em>) compared to conventional solid fins. The analysis further reveals that increasing <em>Re</em> decreases thermal resistance at the expense of a higher pressure drop, while lower porosity enhances heat transfer at the cost of increased flow resistance. Crucially, the favorable porous height for <em>PEF</em> decreases with higher <em>Re</em>, emphasizing the necessity for a flow-condition-specific design to maximize the benefits of this hybrid approach.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110210"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-17DOI: 10.1016/j.ijheatfluidflow.2025.110180
Deepak Kumar Rathaur, R.M. Sarviya, S.P.S. Rajput
The rising global demand for compact, energy-efficient heat exchangers has driven interest in passive heat transfer enhancement techniques. Among these, the combination of twisted tape inserts with nanofluids is particularly promising, as twisted tapes generate swirl flows that enhance heat transfer, while nanofluids improve thermal conductivity without requiring extra energy. This review systematically synthesizes experimental and numerical studies on single, hybrid, and tri-hybrid nanofluids combined with classical and modified twisted tape inserts, including perforated, wavy, jagged, wing-cut, V-cut, W-cut, and compound designs. Performance is evaluated in terms of Nusselt number, friction factor, and thermal performance factor. Classical twisted tape inserts with single nanofluid enhance heat transfer by 15–40 %, whereas advanced geometries with hybrid nanofluids achieve 50–95 % gains. The maximum reported Nusselt number enhancement is approximately 72% for hybrid nanofluids with modified twisted tape inserts at higher Reynolds numbers, accompanied by a 20–60 % increase in friction factor. Thermal performance factors generally exceed unity, peaking at around 2.5 for a helical coil–twisted tape insert configuration with graphene/water nanofluid. Comparisons indicate that plain twisted tape inserts with Al2O3/water nanofluid improve heat transfer by about 40%, while perforated twisted tape inserts with Al2O3-Cu/water hybrid nanofluids achieve approximately 85%. Overall, geometry modification combined with advanced nanofluids can nearly double heat exchanger performance, although challenges related to pumping power, nanofluid stability, and techno-economic feasibility remain key areas for future research.
全球对紧凑型、高能效热交换器的需求不断增长，推动了人们对被动传热增强技术的兴趣。其中，扭曲带与纳米流体的结合尤其有前景，因为扭曲带产生漩涡流动，加强传热，而纳米流体在不需要额外能量的情况下提高导热性。本文系统地综合了单一、混合和三混合纳米流体与经典和改进的扭曲带插入物结合的实验和数值研究，包括穿孔、波浪、锯齿、翼形切割、v形切割、w形切割和复合设计。性能是根据努塞尔数、摩擦系数和热性能系数来评估的。传统的扭曲带插入与单一纳米流体提高传热15 - 40%，而先进的几何形状与混合纳米流体实现50 - 95%的增益。据报道，在较高雷诺数下，混合纳米流体的最大努塞尔数增强约为72%，同时摩擦系数增加20 - 60%。热性能系数通常超过1，对于带有石墨烯/水纳米流体的螺旋线圈扭曲带插入配置，热性能系数在2.5左右达到峰值。对比表明，普通的扭曲带插入Al2O3/水纳米流体可以提高约40%的换热率，而穿孔扭曲带插入Al2O3- cu /水混合纳米流体可以提高约85%的换热率。总体而言，尽管泵送功率、纳米流体稳定性和技术经济可行性仍是未来研究的关键领域，但与先进纳米流体相结合的几何形状改变可以使热交换器的性能几乎翻倍。
{"title":"Synergistic enhancement of heat transfer in tubular heat exchangers using twisted tape inserts and nanofluids: An integrated numerical and experimental review","authors":"Deepak Kumar Rathaur, R.M. Sarviya, S.P.S. Rajput","doi":"10.1016/j.ijheatfluidflow.2025.110180","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110180","url":null,"abstract":"<div><div>The rising global demand for compact, energy-efficient heat exchangers has driven interest in passive heat transfer enhancement techniques. Among these, the combination of twisted tape inserts with nanofluids is particularly promising, as twisted tapes generate swirl flows that enhance heat transfer, while nanofluids improve thermal conductivity without requiring extra energy. This review systematically synthesizes experimental and numerical studies on single, hybrid, and tri-hybrid nanofluids combined with classical and modified twisted tape inserts, including perforated, wavy, jagged, wing-cut, V-cut, W-cut, and compound designs. Performance is evaluated in terms of Nusselt number, friction factor, and thermal performance factor. Classical twisted tape inserts with single nanofluid enhance heat transfer by 15–40 %, whereas advanced geometries with hybrid nanofluids achieve 50–95 % gains. The maximum reported Nusselt number enhancement is approximately 72% for hybrid nanofluids with modified twisted tape inserts at higher Reynolds numbers, accompanied by a 20–60 % increase in friction factor. Thermal performance factors generally exceed unity, peaking at around 2.5 for a helical coil–twisted tape insert configuration with graphene/water nanofluid. Comparisons indicate that plain twisted tape inserts with Al<sub>2</sub>O<sub>3</sub>/water nanofluid improve heat transfer by about 40%, while perforated twisted tape inserts with Al<sub>2</sub>O<sub>3</sub>-Cu/water hybrid nanofluids achieve approximately 85%. Overall, geometry modification combined with advanced nanofluids can nearly double heat exchanger performance, although challenges related to pumping power, nanofluid stability, and techno-economic feasibility remain key areas for future research.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110180"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-22DOI: 10.1016/j.ijheatfluidflow.2025.110212
Anupama Singh , Anand Kumar , Vinod K. Gupta
The current article explores the structure of chaotic convection and the rate of heat transfer in a Rivlin–Ericksen fluid layer with an internal heat source flowing through a highly permeable porous medium that is heated from below. The truncated Galerkin approximation has produced a low-dimensional system similar to the Lorenz model. To compute the numerical simulation for a Lorenz-like equation framework, we implemented the fourth-order Runge–Kutta method. We utilized MATHEMATICA software for quantitative analysis and MATLAB software for visualization. The influence of an internal heat content on chaotic convection has been investigated. Additionally, when comparing only the elasticity effect, we found that the Rayleigh number decreases by 8.09%. This indicates that the chaotic behavior predominates over the instability of the system. We discovered that both the level of internal heat and the elastic parameter enhance chaotic convection. We propose that the level of internal heat influences the transition from steady to chaotic convection.
{"title":"Insight into effect of internal heating on natural convection of Rivlin–Ericksen fluid with highly permeable porous medium: Dynamical system approach","authors":"Anupama Singh , Anand Kumar , Vinod K. Gupta","doi":"10.1016/j.ijheatfluidflow.2025.110212","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110212","url":null,"abstract":"<div><div>The current article explores the structure of chaotic convection and the rate of heat transfer in a Rivlin–Ericksen fluid layer with an internal heat source flowing through a highly permeable porous medium that is heated from below. The truncated Galerkin approximation has produced a low-dimensional system similar to the Lorenz model. To compute the numerical simulation for a Lorenz-like equation framework, we implemented the fourth-order Runge–Kutta method. We utilized MATHEMATICA software for quantitative analysis and MATLAB software for visualization. The influence of an internal heat content on chaotic convection has been investigated. Additionally, when comparing only the elasticity effect, we found that the Rayleigh number decreases by 8.09%. This indicates that the chaotic behavior predominates over the instability of the system. We discovered that both the level of internal heat and the elastic parameter enhance chaotic convection. We propose that the level of internal heat influences the transition from steady to chaotic convection.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110212"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-24DOI: 10.1016/j.ijheatfluidflow.2025.110224
Shao-Fei Zheng , Jia-Xing Meng , Hua-Dong Shi , Yi-Feng Wang , Shu-Rong Gao , Yan-Ru Yang , Bo Gao , Xiao-Dong Wang
In gas turbine engines, efficient heat transfer following less friction loss is extremely preferable for the cooling of turbine blades, because of the limited supply of the cooling air. To maximize the cooling effect of the commonly utilized ribbed channel, the back propagation neural network (BPNN) model and the genetic algorithm (GA) are combined to construct an optimization tool by exactly modeling the complex nonlinear relationship between the influencing factors and cooling performance. The coupling influences of the channel aspect ratio (W/H = 0.5 ∼ 4.0), the pitch ratio of ribs (P/e = 20 ∼ 5), and the Reynolds number (Re = 20, 000 ∼ 100, 000) are comprehensively analyzed using the Nusselt number and overall performance factor as the target function. The results state that using the Nusselt number as the target function, the relatively large aspect ratio and small pitch ratio are recommended due to the heat transfer enhancement of the flow impingement effect with the rib-induced flow separation. Considering both the heat transfer enhancement and the increased friction loss, the overall performance factor presents a highly nonlinear relationship with those influencing parameters, and the relatively small aspect ratio and large pitch ratio are suggested to improve the comprehensive cooling performance. Using the GA-BPNN optimization method, a great increase of 16.98 %∼30.67 % is achieved for the overall performance factor in the current operating conditions. Finally, the GA-BPNN method is demonstrated as powerful and efficient for improving the ribbed cooling channel.
在燃气涡轮发动机中，由于冷却空气的供应有限，在摩擦损失较小的情况下，高效的传热对于涡轮叶片的冷却是极其可取的。为了使常用的肋形通道冷却效果最大化，将反向传播神经网络（BPNN）模型与遗传算法（GA）相结合，通过精确建模影响因素与冷却性能之间复杂的非线性关系，构建了优化工具。耦合通道宽高比的影响(0.5 W / H = ∼ 4.0),肋骨的螺距比(P / e = 20 ∼ 5),和雷诺数(Re = 000 ∼ 100年,000年)进行了全面分析使用努塞尔特数和整体性能因素作为目标函数。结果表明，以Nusselt数为目标函数，由于肋诱导流动分离强化了流动冲击效应的传热，建议采用较大的展弦比和较小的节距比。考虑到传热增强和摩擦损失的增加，综合性能因子与这些影响参数呈高度非线性关系，建议采用较小的展弦比和较大的节距比来提高综合冷却性能。使用GA-BPNN优化方法，在当前运行条件下，总体性能因子实现了16.98 % ~ 30.67 %的大幅提高。最后，验证了GA-BPNN方法对肋形冷却通道的改进效果。
{"title":"Optimization of the cooling performance of ribbed channels by combining neural networks and genetic algorithms","authors":"Shao-Fei Zheng , Jia-Xing Meng , Hua-Dong Shi , Yi-Feng Wang , Shu-Rong Gao , Yan-Ru Yang , Bo Gao , Xiao-Dong Wang","doi":"10.1016/j.ijheatfluidflow.2025.110224","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110224","url":null,"abstract":"<div><div>In gas turbine engines, efficient heat transfer following less friction loss is extremely preferable for the cooling of turbine blades, because of the limited supply of the cooling air. To maximize the cooling effect of the commonly utilized ribbed channel, the back propagation neural network (BPNN) model and the genetic algorithm (GA) are combined to construct an optimization tool by exactly modeling the complex nonlinear relationship between the influencing factors and cooling performance. The coupling influences of the channel aspect ratio (<em>W</em>/<em>H</em> = 0.5 ∼ 4.0), the pitch ratio of ribs (<em>P</em>/<em>e</em> = 20 ∼ 5), and the Reynolds number (<em>Re</em> = 20, 000 ∼ 100, 000) are comprehensively analyzed using the Nusselt number and overall performance factor as the target function. The results state that using the Nusselt number as the target function, the relatively large aspect ratio and small pitch ratio are recommended due to the heat transfer enhancement of the flow impingement effect with the rib-induced flow separation. Considering both the heat transfer enhancement and the increased friction loss, the overall performance factor presents a highly nonlinear relationship with those influencing parameters, and the relatively small aspect ratio and large pitch ratio are suggested to improve the comprehensive cooling performance. Using the GA-BPNN optimization method, a great increase of 16.98 %∼30.67 % is achieved for the overall performance factor in the current operating conditions. Finally, the GA-BPNN method is demonstrated as powerful and efficient for improving the ribbed cooling channel.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110224"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-20DOI: 10.1016/j.ijheatfluidflow.2025.110218
Zhen Xiang , Qilong Liu , Shaohua Han , Shizhen Qi , Tianyi Huo , Runsheng Zhang , Leping Zhou , Li Li , Hui Zhang , Xiaoze Du
Improving the cooling effectiveness of turbine blade squealer tip regions under high thermal loads remains a challenge in designing of gas turbines. This study numerically investigates the cooling performance of a novel protrusion-V-rib composite structure applied to the internal U-channel near the blade squealer tip. Eight configurations, including holed/hole free designs and combinations of V-ribs, protrusions and vanes, are evaluated at Re = 10,000–50,000. Key findings show that holed structures enhance heat transfer near holes due to accelerated fluid velocity and increased turbulence, resulting in higher Nusselt number. However, hole free configurations exhibit superior downstream heat transfer (up to 4.14 % improvement) by maintaining coolant mass flow. Complex geometries, particularly the V-Convex design, significantly suppress flow separation and reduce vortex size by promoting fluid disturbance and turbulence. The V-convex structure exhibits the highest Nusselt number and comprehensive thermal performance factor under both constant temperature and constant heat flux boundary conditions, confirming its robustness. The results highlight the trade-off between local heat transfer enhancement (holed structures) and downstream cooling effectiveness (hole-free designs), emphasizing the importance of geometric optimization for blade squealer tip cooling. This work helps understand the composite cooling structures and provides insights for efficient thermal management in applications of high-temperature turbines.
{"title":"Enhanced cooling performance in turbine blade tip U-channel using protrusion-V-rib composite structure","authors":"Zhen Xiang , Qilong Liu , Shaohua Han , Shizhen Qi , Tianyi Huo , Runsheng Zhang , Leping Zhou , Li Li , Hui Zhang , Xiaoze Du","doi":"10.1016/j.ijheatfluidflow.2025.110218","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110218","url":null,"abstract":"<div><div>Improving the cooling effectiveness of turbine blade squealer tip regions under high thermal loads remains a challenge in designing of gas turbines. This study numerically investigates the cooling performance of a novel protrusion-V-rib composite structure applied to the internal U-channel near the blade squealer tip. Eight configurations, including holed/hole free designs and combinations of V-ribs, protrusions and vanes, are evaluated at Re = 10,000–50,000. Key findings show that holed structures enhance heat transfer near holes due to accelerated fluid velocity and increased turbulence, resulting in higher Nusselt number. However, hole free configurations exhibit superior downstream heat transfer (up to 4.14 % improvement) by maintaining coolant mass flow. Complex geometries, particularly the V-Convex design, significantly suppress flow separation and reduce vortex size by promoting fluid disturbance and turbulence. The V-convex structure exhibits the highest Nusselt number and comprehensive thermal performance factor under both constant temperature and constant heat flux boundary conditions, confirming its robustness. The results highlight the trade-off between local heat transfer enhancement (holed structures) and downstream cooling effectiveness (hole-free designs), emphasizing the importance of geometric optimization for blade squealer tip cooling. This work helps understand the composite cooling structures and provides insights for efficient thermal management in applications of high-temperature turbines.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110218"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-30DOI: 10.1016/j.ijheatfluidflow.2025.110222
Qifeng Zhu, He Zhao, Jingwei Zeng, Sen Zhang, Wenqiang He, Haoxin Deng, Zezhong Wang
Previous research has demonstrated that symmetric sinusoidal wavy (SSW) microchannel heat sinks with rectangular ribs enhance heat transfer compared to ribless SSW channels. To further clarify the role of rib geometry, we conduct numerical simulations to analyze the effects of rib cross-sectional shape on flow and heat transfer characteristics in SSW channels using entransy dissipation and field synergy theory. The channels are equipped with internal ribs of six cross-sectional shapes (airfoil, backward triangle, diamond, ellipse, forward triangle and rectangle). The results show that the addition of ribs significantly improved the heat transfer, with the rectangular rib configuration (SSW-RR) achieving the highest overall performance factor of 1.227 at Re = 600. Ribs reduce entransy dissipation in channel troughs while generating high dissipation near flow detachment points, and this effect intensifies at higher Reynolds numbers. SSW-RR exhibits the lowest entransy dissipation values (1.20 × 1010 to 6.76 × 109), indicating optimal heat transfer performance. Flow field analysis reveals that reverse vortices and large-angle fluid deflection enhance heat transfer, with the forward triangular rib configuration (SSW-FTR) showing the best field synergy (83.58 at Re = 300).
{"title":"Numerical analysis of rib shape effects on entransy and field synergy in a ribbed sinusoidal wavy microchannel","authors":"Qifeng Zhu, He Zhao, Jingwei Zeng, Sen Zhang, Wenqiang He, Haoxin Deng, Zezhong Wang","doi":"10.1016/j.ijheatfluidflow.2025.110222","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110222","url":null,"abstract":"<div><div>Previous research has demonstrated that symmetric sinusoidal wavy (SSW) microchannel heat sinks with rectangular ribs enhance heat transfer compared to ribless SSW channels. To further clarify the role of rib geometry, we conduct numerical simulations to analyze the effects of rib cross-sectional shape on flow and heat transfer characteristics in SSW channels using entransy dissipation and field synergy theory. The channels are equipped with internal ribs of six cross-sectional shapes (airfoil, backward triangle, diamond, ellipse, forward triangle and rectangle). The results show that the addition of ribs significantly improved the heat transfer, with the rectangular rib configuration (SSW-RR) achieving the highest overall performance factor of 1.227 at <em>Re</em> = 600. Ribs reduce entransy dissipation in channel troughs while generating high dissipation near flow detachment points, and this effect intensifies at higher Reynolds numbers. SSW-RR exhibits the lowest entransy dissipation values (1.20 × 10<sup>10</sup> to 6.76 × 10<sup>9</sup>), indicating optimal heat transfer performance. Flow field analysis reveals that reverse vortices and large-angle fluid deflection enhance heat transfer, with the forward triangular rib configuration (SSW-FTR) showing the best field synergy (83.58 at <em>Re</em> = 300).</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110222"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-15DOI: 10.1016/j.ijheatfluidflow.2025.110203
Mohanaphriya US, Tanmoy Chakraborty
<div><div>This objective of this study is to investigate the influence of nanoparticles (NPs) shapes — spherical, cylindrical, brick-like, and platelet — on stagnation-point flow and heat transfer in a Prandtl–Eyring hybrid nanofluid over a vertical Riga plate. Prandtl–Eyring fluid is considered as engine oil, with the suspension of <span><math><mrow><mi>C</mi><mi>u</mi></mrow></math></span> and <span><math><mrow><mi>Z</mi><mi>r</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span> nanoparticles. The analysis includes generalized Fourier heat conduction using the Cattaneo–Christov model along with solar radiation, and convective boundary conditions. Numerical solutions are obtained using the MATLAB’s stiff ordinary differential equation solver ode15s and optimized using the Matlab trust-region reflective algorithm. Results reveal that the Prandtl–Eyring parameters reduce the velocity but enhance temperature, while platelet-shaped nanoparticles yield the highest skin friction and heat transfer performance. A marginal 0.027% rise in the skin friction and up to 20.84% reduction in the rate of heat transportation are perceived across all the shapes within the relaxation time parameter (<span><math><mi>ξ</mi></math></span>) ranging between <span><math><mrow><mn>0</mn><mo>.</mo><mn>0</mn><mo>≤</mo><mi>ξ</mi><mo>≤</mo><mn>0</mn><mo>.</mo><mn>2</mn></mrow></math></span>. Furthermore, Entropy generation could be minimized by lowering the unsteadiness parameter and modified Hartmann number. Statistical analysis shows that the solar radiation parameter (<span><math><mi>R</mi></math></span>) has the most significant impact (70.35%) on the heat transfer, while the Prandtl–Eyring parameter 1 (<span><math><msup><mrow><mi>α</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span>) has the least (0.002%) impact. Based on the Taguchi optimization, the optimal parameter levels for maximizing heat transfer for the spherically shaped nanoparticles are: <span><math><msup><mrow><mi>α</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span> (Prandtl–Eyring parameter 1) <span><math><mrow><mo>=</mo><mn>1</mn><mo>.</mo><mn>2</mn></mrow></math></span>, <span><math><msup><mrow><mi>β</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span> (Prandtl–Eyring parameter 2) <span><math><mrow><mo>=</mo><mn>0</mn><mo>.</mo><mn>2</mn></mrow></math></span>, <span><math><mi>Z</mi></math></span> (modified Hartmann number) <span><math><mrow><mo>=</mo><mn>1</mn><mo>.</mo><mn>5</mn></mrow></math></span>, <span><math><mi>ξ</mi></math></span> (relaxation time parameter) <span><math><mrow><mo>=</mo><mn>0</mn><mo>.</mo><mn>2</mn></mrow></math></span>, <span><math><mi>R</mi></math></span> (Solar Radiation parameter) <span><math><mrow><mo>=</mo><mn>1</mn><mo>.</mo><mn>0</mn></mrow></math></span>, <span><math><mi>γ</mi></math></span> (surface convection parameter) <span><math><mrow><mo>=</mo><mn>15</mn></mrow></math></span>. Under these conditions, the maximum heat tran
{"title":"Taguchi analysis on convective heat transfer of a Prandtl-Eyring hybrid nanofluid over a Riga plate: Entropy optimization","authors":"Mohanaphriya US, Tanmoy Chakraborty","doi":"10.1016/j.ijheatfluidflow.2025.110203","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110203","url":null,"abstract":"<div><div>This objective of this study is to investigate the influence of nanoparticles (NPs) shapes — spherical, cylindrical, brick-like, and platelet — on stagnation-point flow and heat transfer in a Prandtl–Eyring hybrid nanofluid over a vertical Riga plate. Prandtl–Eyring fluid is considered as engine oil, with the suspension of <span><math><mrow><mi>C</mi><mi>u</mi></mrow></math></span> and <span><math><mrow><mi>Z</mi><mi>r</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span> nanoparticles. The analysis includes generalized Fourier heat conduction using the Cattaneo–Christov model along with solar radiation, and convective boundary conditions. Numerical solutions are obtained using the MATLAB’s stiff ordinary differential equation solver ode15s and optimized using the Matlab trust-region reflective algorithm. Results reveal that the Prandtl–Eyring parameters reduce the velocity but enhance temperature, while platelet-shaped nanoparticles yield the highest skin friction and heat transfer performance. A marginal 0.027% rise in the skin friction and up to 20.84% reduction in the rate of heat transportation are perceived across all the shapes within the relaxation time parameter (<span><math><mi>ξ</mi></math></span>) ranging between <span><math><mrow><mn>0</mn><mo>.</mo><mn>0</mn><mo>≤</mo><mi>ξ</mi><mo>≤</mo><mn>0</mn><mo>.</mo><mn>2</mn></mrow></math></span>. Furthermore, Entropy generation could be minimized by lowering the unsteadiness parameter and modified Hartmann number. Statistical analysis shows that the solar radiation parameter (<span><math><mi>R</mi></math></span>) has the most significant impact (70.35%) on the heat transfer, while the Prandtl–Eyring parameter 1 (<span><math><msup><mrow><mi>α</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span>) has the least (0.002%) impact. Based on the Taguchi optimization, the optimal parameter levels for maximizing heat transfer for the spherically shaped nanoparticles are: <span><math><msup><mrow><mi>α</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span> (Prandtl–Eyring parameter 1) <span><math><mrow><mo>=</mo><mn>1</mn><mo>.</mo><mn>2</mn></mrow></math></span>, <span><math><msup><mrow><mi>β</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span> (Prandtl–Eyring parameter 2) <span><math><mrow><mo>=</mo><mn>0</mn><mo>.</mo><mn>2</mn></mrow></math></span>, <span><math><mi>Z</mi></math></span> (modified Hartmann number) <span><math><mrow><mo>=</mo><mn>1</mn><mo>.</mo><mn>5</mn></mrow></math></span>, <span><math><mi>ξ</mi></math></span> (relaxation time parameter) <span><math><mrow><mo>=</mo><mn>0</mn><mo>.</mo><mn>2</mn></mrow></math></span>, <span><math><mi>R</mi></math></span> (Solar Radiation parameter) <span><math><mrow><mo>=</mo><mn>1</mn><mo>.</mo><mn>0</mn></mrow></math></span>, <span><math><mi>γ</mi></math></span> (surface convection parameter) <span><math><mrow><mo>=</mo><mn>15</mn></mrow></math></span>. Under these conditions, the maximum heat tran","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110203"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-19DOI: 10.1016/j.ijheatfluidflow.2025.110208
Olivier Cadot
Since the first observation of steady symmetry breaking in the turbulent wakes of a square-back Ahmed body by Grandemange et al. (2012), there have been reports of similar effects with ground vehicles of more complex geometries with square-back style, including real vehicles. The article reviews these cases of industrial flows, either at small or full scale in wind tunnels or numerical simulations with and without road effects. A clear consensus appears of asymmetric recirculating flows in the vertical direction that can, with well chosen parametric variations, reverse to the opposite asymmetry and sometimes lead to spectacular vertical bistable dynamics. These global changes of the base flow impact the body drag and lift. The underlying universal property of these wakes is likely the same steady instability as that of the square-back Ahmed body.
{"title":"A review on the asymmetry, steady instability and bistability in the wake of industrial ground vehicles","authors":"Olivier Cadot","doi":"10.1016/j.ijheatfluidflow.2025.110208","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110208","url":null,"abstract":"<div><div>Since the first observation of steady symmetry breaking in the turbulent wakes of a square-back Ahmed body by Grandemange et al. (2012), there have been reports of similar effects with ground vehicles of more complex geometries with square-back style, including real vehicles. The article reviews these cases of industrial flows, either at small or full scale in wind tunnels or numerical simulations with and without road effects. A clear consensus appears of asymmetric recirculating flows in the vertical direction that can, with well chosen parametric variations, reverse to the opposite asymmetry and sometimes lead to spectacular vertical bistable dynamics. These global changes of the base flow impact the body drag and lift. The underlying universal property of these wakes is likely the same steady instability as that of the square-back Ahmed body.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110208"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optimal thermal regulation in battery modules is critical for maintaining the efficient and reliable operation of battery packs. This study designed an active immersion cooling system for prismatic lithium-ion battery modules, demonstrating maximum temperature reductions of 34 % and 47.7 % relative to static submersion cooling and free convection methods, respectively. The impacts of coolant flow rate, flow direction, and module arrangement patterns on forced-flow immersion cooling performance were numerically investigated. Results indicate that parallel battery arrangements show superior cooling performance compared to staggered configurations. Among the five flow patterns (top to bottom, bottom to top, top to top, bottom to bottom, and center to center), the top to bottom layout exhibits the optimal cooling efficiency. As the inlet flow rate increases, both the maximum battery temperature and the temperature difference across the battery pack first drop sharply and then slowly after the flow rate reaches 0.023 kg/s. Power consumption demonstrates a positive relationship with inlet velocity, whereas the cooling index shows an inverse relationship. As the horizontal spacing between batteries varies from 1 to 6 mm, the maximum temperature of the battery and temperature difference show a “U” shaped trend, the power consumption decreases monotonically, while the cooling index shows a “И” shaped variation trend. Similarly, with the increase of longitudinal distance between batteries, Both the peak battery temperature and temperature differential present a “U” shaped variation trend, and the power dissipation decreases monotonically. Conversely, the cooling index increases monotonously. Finally, a 4-mm horizontal and 5-mm longitudinal spacing were identified as the optimal configuration. This study addressed both operational safety and thermal management efficiency for prismatic lithium-ion batteries, and established design guidelines for high-performance immersion cooling systems.
{"title":"Design and performance optimization of liquid immersion cooling system for prismatic lithium-ion battery modules","authors":"Luyao Zhao, Jiafeng Wang, Minxue Zheng, Mingyi Chen","doi":"10.1016/j.ijheatfluidflow.2025.110181","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110181","url":null,"abstract":"<div><div>Optimal thermal regulation in battery modules<!--> <!-->is critical for maintaining<!--> <!-->the efficient and reliable operation of battery packs. This study designed an active immersion<!--> <!-->cooling system for prismatic lithium-ion battery modules, demonstrating maximum temperature reductions of 34 % and 47.7 % relative to static submersion cooling and free convection methods, respectively. The impacts of coolant flow rate, flow direction, and module arrangement patterns on forced-flow immersion cooling performance were numerically investigated. Results indicate that parallel battery arrangements show superior cooling performance compared to staggered configurations. Among the five flow patterns (top to bottom, bottom to top, top to top, bottom to bottom, and center to center), the top to bottom layout exhibits the optimal cooling efficiency. As the inlet flow rate increases, both the maximum battery temperature and the temperature difference across the battery pack first drop sharply and then slowly after the flow rate reaches 0.023 kg/s. Power consumption demonstrates a positive relationship with inlet velocity, whereas the cooling index shows an inverse relationship. As the horizontal spacing between batteries varies from<!--> <!-->1 to 6 mm, the maximum temperature of the battery and temperature difference show a “U” shaped trend, the power consumption decreases monotonically, while the cooling index shows a “И” shaped variation trend. Similarly, with the increase of longitudinal distance between batteries, Both the peak battery temperature and temperature differential present a “U” shaped variation trend, and the power dissipation decreases monotonically. Conversely, the cooling index increases monotonously. Finally, a 4-mm horizontal and 5-mm longitudinal spacing were identified as the optimal configuration. This study addressed both operational safety and thermal management efficiency for prismatic lithium-ion batteries, and established design guidelines for high-performance immersion cooling systems.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"118 ","pages":"Article 110181"},"PeriodicalIF":2.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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