International Journal of Heat and Fluid Flow最新文献_第4页

In-silico study of intratumoural magnetic hyperthermia in thermoporoelastic liver tissues using Fe3O4 nanoparticles 利用Fe3O4纳米颗粒在热孔弹性肝组织中进行肿瘤内磁热疗的计算机研究

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-15 DOI: 10.1016/j.ijheatfluidflow.2026.110264

Stephon De Souze, Victor M. Job, Mahesha Narayana

In the present study, the effects of magnetic field strength, nanoparticle magnetization, natural convection, tumour blood retention capacity and tumour rigidity on magnetic hyperthermia cancer therapy in malignant liver tissues in a solenoidal magnetic field are considered. The liver tissue region is modelled as a thermoporoelastic healthy liver tissue surrounding a cancerous region. This is achieved by using the Navier–Cauchy equations to describe the deformation of the tissues, Darcy’s law to describe the fluid flow, continuity equation to describe the conservation of mass and the energy equation to describe the temperature distribution within our system. A finite element/finite difference scheme for this system of equations is constructed and implemented via MATLAB R2024a, and the results are simulated graphically. It was found that an increase in magnetic field strength or nanoparticle magnetization significantly increases the tissue temperature and the chance of tissue death within our system. Moreover, it also significantly increases the deformation of the tissues and interstitial blood pressure. Although the blood retention and rigidity of the tumour significantly affect the local blood pressure and the deformation, they have a negligible effect of the temperature and tissue cell death. The major implication of these findings is that the effectiveness of this therapy is not significantly impacted by tumour blood retention capacity or tumour rigidity, but is greatly affected by the magnetic field strength and nanoparticle magnetization.

在本研究中，考虑磁场强度、纳米粒子磁化、自然对流、肿瘤血液潴留能力和肿瘤刚性对电磁磁场下恶性肝组织磁热疗癌症治疗的影响。肝组织区域被建模为围绕癌区域的热孔弹性健康肝组织。这是通过使用纳维-柯西方程来描述组织的变形，达西定律来描述流体流动，连续性方程来描述质量守恒，能量方程来描述系统内的温度分布来实现的。利用MATLAB R2024a构建了该方程组的有限元/有限差分格式，并对结果进行了图形仿真。研究发现，磁场强度或纳米颗粒磁化强度的增加会显著增加我们体内组织的温度和组织死亡的几率。此外，它还显著增加组织变形和间质血压。虽然肿瘤的血液潴留和刚性显著影响局部血压和变形，但它们对温度和组织细胞死亡的影响可以忽略不计。这些发现的主要含义是，这种治疗的有效性不受肿瘤血液潴留能力或肿瘤硬度的显著影响，但受到磁场强度和纳米颗粒磁化的极大影响。

{"title":"In-silico study of intratumoural magnetic hyperthermia in thermoporoelastic liver tissues using Fe3O4 nanoparticles","authors":"Stephon De Souze, Victor M. Job, Mahesha Narayana","doi":"10.1016/j.ijheatfluidflow.2026.110264","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110264","url":null,"abstract":"<div><div>In the present study, the effects of magnetic field strength, nanoparticle magnetization, natural convection, tumour blood retention capacity and tumour rigidity on magnetic hyperthermia cancer therapy in malignant liver tissues in a solenoidal magnetic field are considered. The liver tissue region is modelled as a thermoporoelastic healthy liver tissue surrounding a cancerous region. This is achieved by using the Navier–Cauchy equations to describe the deformation of the tissues, Darcy’s law to describe the fluid flow, continuity equation to describe the conservation of mass and the energy equation to describe the temperature distribution within our system. A finite element/finite difference scheme for this system of equations is constructed and implemented via MATLAB R2024a, and the results are simulated graphically. It was found that an increase in magnetic field strength or nanoparticle magnetization significantly increases the tissue temperature and the chance of tissue death within our system. Moreover, it also significantly increases the deformation of the tissues and interstitial blood pressure. Although the blood retention and rigidity of the tumour significantly affect the local blood pressure and the deformation, they have a negligible effect of the temperature and tissue cell death. The major implication of these findings is that the effectiveness of this therapy is not significantly impacted by tumour blood retention capacity or tumour rigidity, but is greatly affected by the magnetic field strength and nanoparticle magnetization.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110264"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974409","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}

引用次数: 0

Numerical analysis of unsteady vortex evolution and internal flow mechanisms in a three-twisted-blade pump using OpenFOAM 基于OpenFOAM的三扭叶片泵非定常涡演化及内部流动机理数值分析

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-20 DOI: 10.1016/j.ijheatfluidflow.2026.110267

Mengfei Wang , Yang Zhang , Bingchen Liang , Bo Yang , Yonghui Liu

A three-twisted-blade pump was simulated using Delayed Detached Eddy Simulation (DDES) method with Arbitrary Mesh Interface (AMI) technique in OpenFOAM on a structured mesh. The study focused on the pump’s startup process, hydrodynamic behavior and the influence of velocity components on internal flow with different operating conditions. Results reveal that the internal flow rapidly evolves from an initially disordered, weakly turbulent state to a stable structure dominated by strong vortices. Vortices generated at the blade leading edge mark the onset of flow unsteadiness, while the trailing edge and volute regions serve as key areas for energy accumulation and transfer. The inlet pressure fluctuation amplitude increases linearly with flow rate and rotational speed, with slopes of 0.052 and 0.17, respectively. Within the impeller, radial fluid velocity increases and then decreases, peaking at 0.7 R (R: impeller radius). This trend remains consistent across flow rates (ranging from 0.75 Q_n to 1.5 Q_n, where Q_n represents the nominal flow rate) and rotational speeds. At low flow rates and large rotational speeds, vortex shedding from the pressure side of the blade’s leading edge induces unstable, three-dimensional flow separation. As flow rates rise, the flow field becomes more uniform, turbulence decreases, and backflow is mitigated.

采用OpenFOAM软件中任意网格接口（AMI）技术的延迟分离涡流模拟（DDES）方法，在结构化网格上对三扭叶片泵进行了仿真。研究了不同工况下泵的启动过程、流体动力特性以及速度分量对内部流量的影响。结果表明，内部流动从最初的无序、弱湍流状态迅速演变为以强涡为主的稳定结构。在叶片前缘产生的涡标志着流动非定常的开始，而尾缘和蜗壳区域是能量积累和传递的关键区域。进口压力波动幅值随流量和转速线性增加，斜率分别为0.052和0.17。叶轮内径向流体速度先增大后减小，在0.7 R （R：叶轮半径）处达到峰值。这种趋势在流量（从0.75 Qn到1.5 Qn，其中Qn代表名义流量）和转速上保持一致。在低流量和大转速下，叶片前缘压力侧的涡脱落会引起不稳定的三维流动分离。随着流量的增加，流场变得更加均匀，湍流减少，回流减轻。

{"title":"Numerical analysis of unsteady vortex evolution and internal flow mechanisms in a three-twisted-blade pump using OpenFOAM","authors":"Mengfei Wang , Yang Zhang , Bingchen Liang , Bo Yang , Yonghui Liu","doi":"10.1016/j.ijheatfluidflow.2026.110267","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110267","url":null,"abstract":"<div><div>A three-twisted-blade pump was simulated using Delayed Detached Eddy Simulation (DDES) method with Arbitrary Mesh Interface (AMI) technique in OpenFOAM on a structured mesh. The study focused on the pump’s startup process, hydrodynamic behavior and the influence of velocity components on internal flow with different operating conditions. Results reveal that the internal flow rapidly evolves from an initially disordered, weakly turbulent state to a stable structure dominated by strong vortices. Vortices generated at the blade leading edge mark the onset of flow unsteadiness, while the trailing edge and volute regions serve as key areas for energy accumulation and transfer. The inlet pressure fluctuation amplitude increases linearly with flow rate and rotational speed, with slopes of 0.052 and 0.17, respectively. Within the impeller, radial fluid velocity increases and then decreases, peaking at 0.7 <em>R</em> (<em>R</em>: impeller radius). This trend remains consistent across flow rates (ranging from 0.75 <em>Q</em><sub>n</sub> to 1.5 <em>Q</em><sub>n</sub>, where <em>Q</em><sub>n</sub> represents the nominal flow rate) and rotational speeds. At low flow rates and large rotational speeds, vortex shedding from the pressure side of the blade’s leading edge induces unstable, three-dimensional flow separation. As flow rates rise, the flow field becomes more uniform, turbulence decreases, and backflow is mitigated.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110267"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023349","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}

引用次数: 0

Numerical study on coal pyrolysis behavior during carbonization in a coke oven 焦炉炭化过程中煤热解行为的数值研究

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-10 DOI: 10.1016/j.ijheatfluidflow.2026.110302

Selvakumar Kumaresh, Man Young Kim

A one-dimensional transient mathematical model is systematically investigated to analyze the thermal evolution of coal during carbonization in an industrial-scale coke oven. The model incorporates the key physical processes governing coking, including heat conduction, moisture evaporation, condensation, and steam migration within the coal charge. Appropriate initial and boundary conditions are specified to ensure the closure of the energy and mass balance formulations. The governing equations are solved using an implicit Crank–Nicolson scheme, and the model is validated against established numerical results from existing literature. This study examines the temperature evolution of three coal types, and the results show that moisture distribution, plastic-layer thickness, and resolidification temperature strongly influence the transient thermal behavior and volatile release patterns. Temperature-dependent expressions for the specific heat are evaluated using both Einstein’s model and empirical correlations, while the effective thermal conductivity is assessed by considering interstitial gas conduction, evolving porosity, and radiative transfer across fissures in the semi-coke. The model predicts drying times, coking durations, and total heat-input requirements and quantifies the influence of the furnace-wall temperature, initial moisture content, and dry bulk density, thereby enabling the assessment of the operating conditions that promote energy-efficient carbonization. Overall, the model provides a robust framework for interpreting the coupled thermophysical processes that occur during carbonization and offers practical guidance for optimizing coke-oven operation and charge preparation.

系统地研究了一维瞬态数学模型，用于分析工业规模焦炉中煤在炭化过程中的热演化。该模型结合了控制焦化的关键物理过程，包括热传导、水分蒸发、冷凝和煤料内的蒸汽迁移。指定了适当的初始条件和边界条件，以确保能量和质量平衡公式的封闭性。采用隐式Crank-Nicolson格式求解控制方程，并根据已有文献的数值结果对模型进行了验证。研究结果表明，水分分布、塑性层厚度和再固化温度对三种煤的瞬态热行为和挥发分释放模式有重要影响。比热的温度依赖表达式使用爱因斯坦模型和经验相关性进行评估，而有效导热系数通过考虑间隙气体传导、孔隙度变化和半焦裂缝间的辐射传递来评估。该模型预测干燥时间、焦化持续时间和总热输入需求，并量化炉壁温度、初始水分含量和干堆密度的影响，从而能够评估促进节能碳化的操作条件。总体而言，该模型为解释碳化过程中发生的耦合热物理过程提供了一个强大的框架，并为优化焦炉操作和炉料制备提供了实用指导。

{"title":"Numerical study on coal pyrolysis behavior during carbonization in a coke oven","authors":"Selvakumar Kumaresh, Man Young Kim","doi":"10.1016/j.ijheatfluidflow.2026.110302","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110302","url":null,"abstract":"<div><div>A one-dimensional transient mathematical model is systematically investigated to analyze the thermal evolution of coal during carbonization in an industrial-scale coke oven. The model incorporates the key physical processes governing coking, including heat conduction, moisture evaporation, condensation, and steam migration within the coal charge. Appropriate initial and boundary conditions are specified to ensure the closure of the energy and mass balance formulations. The governing equations are solved using an implicit Crank–Nicolson scheme, and the model is validated against established numerical results from existing literature. This study examines the temperature evolution of three coal types, and the results show that moisture distribution, plastic-layer thickness, and resolidification temperature strongly influence the transient thermal behavior and volatile release patterns. Temperature-dependent expressions for the specific heat are evaluated using both Einstein’s model and empirical correlations, while the effective thermal conductivity is assessed by considering interstitial gas conduction, evolving porosity, and radiative transfer across fissures in the semi-coke. The model predicts drying times, coking durations, and total heat-input requirements and quantifies the influence of the furnace-wall temperature, initial moisture content, and dry bulk density, thereby enabling the assessment of the operating conditions that promote energy-efficient carbonization. Overall, the model provides a robust framework for interpreting the coupled thermophysical processes that occur during carbonization and offers practical guidance for optimizing coke-oven operation and charge preparation.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110302"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170019","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}

引用次数: 0

Numerical investigation on compound heat-transfer enhancement in pin-fin-enhanced double-layer staggered-cavity microchannels 针翅强化双层交错腔微通道复合传热强化的数值研究

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-09 DOI: 10.1016/j.ijheatfluidflow.2026.110250

Tianyu Wu, Yuhao Gao, Xinxin Ren, Jianqiu Zhou

To satisfy the ever-increasing heat flux (>1 kW cm⁻²) of high-power microelectronics, we perform steady, laminar CFD simulations (validated against existing experiments with friction-factor deviations within 6.9 % and Nusselt-number deviations within 2.4 %) to compare three microchannel architectures: (i) straight rectangular, (ii) double-layer staggered-cavity, and (iii) staggered-cavity with circular pin–fin ribs. For the first time, systematic parametric sweeps (Re = 100–800, cavity depth = 30–70 µm, cavity-pitch-to-hydraulic-diameter ratio = 0.03–0.12) quantify the synergistic boundary-layer disruption generated by cavity-driven vortices and the jet-impingement/recirculation induced by pin fins. Compared with the straight channel, the composite design increases Nu by 9.6–19.8 % while raising the Darcy friction factor by 26–52 %. When both geometries are compared at equal pumping power (PEC), the composite channel yields superior thermo-hydraulic performance below Re ≈ 300 (maximum PEC = 1.13 at Re = 300, depth = 60 µm, pitch/D_h = 0.06), whereas the cavity-only configuration becomes advantageous at higher Reynolds numbers, offering clear design guidelines for practical applications.

为了满足大功率微电子不断增加的热流（>1 kW cm−2），我们进行了稳定的层流CFD模拟（根据现有实验验证，摩擦因子偏差在6.9%以内，努selselt数偏差在2.4%以内）来比较三种微通道架构：(i)直矩形，（ii）双层交错腔，（iii）带圆形鳍状肋的交错腔。系统参数扫描（Re = 100-800，空腔深度= 30-70µm，空腔距-水力-直径比= 0.03-0.12）首次量化了由空腔驱动的涡流和针翼诱导的射流撞击/再循环所产生的协同边界层破坏。与直通道相比，复合设计使Nu提高了9.6 ~ 19.8%，达西摩擦系数提高了26 ~ 52%。当两种几何形状在等泵功率（PEC）下进行比较时，复合通道在Re≈300以下具有优越的热水力性能（Re = 300时最大PEC = 1.13，深度= 60µm，节距/Dh = 0.06），而在更高雷诺数下，仅空腔结构具有优势，为实际应用提供了明确的设计指导。

{"title":"Numerical investigation on compound heat-transfer enhancement in pin-fin-enhanced double-layer staggered-cavity microchannels","authors":"Tianyu Wu, Yuhao Gao, Xinxin Ren, Jianqiu Zhou","doi":"10.1016/j.ijheatfluidflow.2026.110250","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110250","url":null,"abstract":"<div><div>To satisfy the ever-increasing heat flux (>1 kW cm<sup>−2</sup>) of high-power microelectronics, we perform steady, laminar CFD simulations (validated against existing experiments with friction-factor deviations within 6.9 % and Nusselt-number deviations within 2.4 %) to compare three microchannel architectures: (i) straight rectangular, (ii) double-layer staggered-cavity, and (iii) staggered-cavity with circular pin–fin ribs. For the first time, systematic parametric sweeps (Re = 100–800, cavity depth = 30–70 µm, cavity-pitch-to-hydraulic-diameter ratio = 0.03–0.12) quantify the synergistic boundary-layer disruption generated by cavity-driven vortices and the jet-impingement/recirculation induced by pin fins. Compared with the straight channel, the composite design increases <em>Nu</em> by 9.6–19.8 % while raising the Darcy friction factor by 26–52 %. When both geometries are compared at equal pumping power (PEC), the composite channel yields superior thermo-hydraulic performance below Re ≈ 300 (maximum PEC = 1.13 at Re = 300, depth = 60 µm, pitch/D<sub>h</sub> = 0.06), whereas the cavity-only configuration becomes advantageous at higher Reynolds numbers, offering clear design guidelines for practical applications.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110250"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923204","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}

引用次数: 0

Cross scale study on the evaporation process of wet metallic wire mesh layer and its heat dissipation performance analysis 湿金属丝网层蒸发过程的交叉尺度研究及其散热性能分析

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-03 DOI: 10.1016/j.ijheatfluidflow.2025.110232

Zhongtao Bai, Xiaoyu Jia, Haoran Zhao, Jian Yang, Mei Lin, Qiuwang Wang

The surface microstructure of a copper mesh was first etched and modified to fabricate an ultra‑thin, hydrophilic wicking core capable of delivering liquid water while dissipating heat through evaporation. At the interfacial scale, a “stepwise wetting” process was for the first time revealed by high‑speed microscopic observation: liquid bridges were observed to nucleate at warp‑weft intersections and subsequently propagate across the mesh node by node, with the subsequent drying stage likewise dominated by the behavior of liquid bridges. The wetting rate of the mesh was found to accelerate with increasing mesh number, while the evaporation process was observed to intensify at higher mesh counts. At the macroscopic scale, a coupled heat‑and‑mass‑transfer model was established, demonstrating that the unsaturated evaporation process can be clearly divided into an externally controlled constant‑rate period (approximately 500 s) and an internally limited falling‑rate period. Evaporation efficiency was effectively enhanced by adopting a graded structure with finer pores at the bottom and coarser pores at the top, combined with reduced layer thickness. For saturated evaporation, the evaporative heat‑transfer coefficient was maintained stable above 30 W· m⁻²· K⁻¹ and conductive thermal resistance was minimized by keeping the stacked structure in a fully saturated state; under such conditions, the overall heat‑transfer coefficient was primarily governed by airflow conditions and structural thickness. Through interfacial‑scale visualization experiments and macroscopic‑scale numerical modeling, a cross‑scale systematic investigation of the evaporation process in moist wire‑mesh thin layers was achieved. Important guidance for the performance optimization of plate‑type heat sinks in transformers is provided by these findings.

首先蚀刻和修改铜网的表面微观结构，以制造超薄的亲水芯芯，能够输送液态水，同时通过蒸发散热。在界面尺度上，高速显微观察首次揭示了“逐步润湿”过程：观察到液体桥在经纬交叉处成核，随后在网格上一个节点一个节点地传播，随后的干燥阶段同样由液体桥的行为主导。网格的润湿速率随着网格数的增加而加快，而蒸发过程随着网格数的增加而加剧。在宏观尺度上，建立了传热传质耦合模型，表明非饱和蒸发过程可以明确地分为外部控制的恒速率周期（约500 s）和内部限制的降速率周期。采用底部细孔、顶部粗孔的梯度结构，并减小层厚，可有效提高蒸发效率。对于饱和蒸发，通过保持层叠结构处于完全饱和状态，蒸发换热系数稳定在30 W·m−2·K−1以上，传导热阻最小；在这种情况下，总体换热系数主要受气流条件和结构厚度的影响。通过界面尺度的可视化实验和宏观尺度的数值模拟，对湿丝网薄层中的蒸发过程进行了跨尺度的系统研究。这些发现为变压器板式散热器的性能优化提供了重要的指导。

{"title":"Cross scale study on the evaporation process of wet metallic wire mesh layer and its heat dissipation performance analysis","authors":"Zhongtao Bai, Xiaoyu Jia, Haoran Zhao, Jian Yang, Mei Lin, Qiuwang Wang","doi":"10.1016/j.ijheatfluidflow.2025.110232","DOIUrl":"10.1016/j.ijheatfluidflow.2025.110232","url":null,"abstract":"<div><div>The surface microstructure of a copper mesh was first etched and modified to fabricate an ultra‑thin, hydrophilic wicking core capable of delivering liquid water while dissipating heat through evaporation. At the interfacial scale, a “stepwise wetting” process was for the first time revealed by high‑speed microscopic observation: liquid bridges were observed to nucleate at warp‑weft intersections and subsequently propagate across the mesh node by node, with the subsequent drying stage likewise dominated by the behavior of liquid bridges. The wetting rate of the mesh was found to accelerate with increasing mesh number, while the evaporation process was observed to intensify at higher mesh counts. At the macroscopic scale, a coupled heat‑and‑mass‑transfer model was established, demonstrating that the unsaturated evaporation process can be clearly divided into an externally controlled constant‑rate period (approximately 500 s) and an internally limited falling‑rate period. Evaporation efficiency was effectively enhanced by adopting a graded structure with finer pores at the bottom and coarser pores at the top, combined with reduced layer thickness. For saturated evaporation, the evaporative heat‑transfer coefficient was maintained stable above 30 W· m<sup>−2</sup>· K<sup>−1</sup> and conductive thermal resistance was minimized by keeping the stacked structure in a fully saturated state; under such conditions, the overall heat‑transfer coefficient was primarily governed by airflow conditions and structural thickness. Through interfacial‑scale visualization experiments and macroscopic‑scale numerical modeling, a cross‑scale systematic investigation of the evaporation process in moist wire‑mesh thin layers was achieved. Important guidance for the performance optimization of plate‑type heat sinks in transformers is provided by these findings.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110232"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145883282","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}

引用次数: 0

Heat transfer and time-dependent flow of an impinging jet on a heated substrate mounted vertically downward or vertically upward 垂直向下或垂直向上安装的加热基板上的冲击射流的传热和随时间的流动

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-06 DOI: 10.1016/j.ijheatfluidflow.2026.110289

Wang Tianshu, Akane Uemichi, Ken-ichiro Tanoue

Heat transfer and time-dependent flow of an impinging jet on a heated substrate mounted vertically downward (

+ g

) or vertically upward (

- g

) have been studied for various hole diameters of inlet d_H and gas flow rate Q_H2 in order to investigate suitable conditions for chemical vapor deposition (CVD). For the

+ g

condition, vortices due to forced convection and natural convection at steady state, except for particular experimental conditions, were almost always observed in the neighborhood of the impinging jet flow. On the other hand, for the

- g

condition, there was no vortex and no “flow separation phenomena” (Shekhar et al., 2014) and the fluid flow was at steady state. The Nu distribution was evaluated by the Richardson number, Ri. The average Nu increased slightly with + Ri for

+ g

while the average Nu decreased with −Ri for

- g

. In these experimental conditions, there was a suitable condition for CVD for -240 < Ri < -160 whereby the deviation of the Nusselt number along the radial position on the heated substrate was less than 0.2. Time-dependent flow with a time period of 2.7 s was observed due to the collision of fresh hydrogen flow and buoyant upward flow on a heated disc at 0.05 < S_H/S_C (open area ratio of the hole to the cylindrical flow channel) < 0.1 and Ri < 100 for

+ g

.

为了研究化学气相沉积（CVD）的适宜条件，研究了不同进口孔径dH和气体流速QH2条件下，垂直向下（+g）或垂直向上（-g）安装在加热基板上的冲击射流的传热和随时间变化的流动。在+g条件下，除特殊实验条件外，在撞击射流附近几乎都能观测到强迫对流和自然对流引起的稳态涡旋。另一方面，在-g条件下，不存在涡流，不存在“流动分离现象”（Shekhar et al., 2014），流体流动处于稳态。Nu分布由理查德森数Ri表示。对于+g，平均Nu值随着+ Ri的增加略有增加，而对于-g，平均Nu值随着- Ri的减小而减小。在这些实验条件下，CVD的适宜条件为-240 <； Ri < -160，此时被加热基片上的努塞尔数沿径向位置的偏差小于0.2。在0.05 < SH/SC（孔洞与圆柱形流道的开面积比）<； 0.1和+g时Ri <； 100时，在加热盘上观察到新鲜氢流与浮力向上流动的碰撞，时间周期为2.7 s。

{"title":"Heat transfer and time-dependent flow of an impinging jet on a heated substrate mounted vertically downward or vertically upward","authors":"Wang Tianshu, Akane Uemichi, Ken-ichiro Tanoue","doi":"10.1016/j.ijheatfluidflow.2026.110289","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110289","url":null,"abstract":"<div><div>Heat transfer and time-dependent flow of an impinging jet on a heated substrate mounted vertically downward (<span><math><mrow><mo>+</mo><mi>g</mi></mrow></math></span>) or vertically upward (<span><math><mrow><mo>-</mo><mi>g</mi></mrow></math></span>) have been studied for various hole diameters of inlet <em>d</em><sub>H</sub> and gas flow rate <em>Q</em><sub>H2</sub> in order to investigate suitable conditions for chemical vapor deposition (CVD). For the <span><math><mrow><mo>+</mo><mi>g</mi></mrow></math></span> condition, vortices due to forced convection and natural convection at steady state, except for particular experimental conditions, were almost always observed in the neighborhood of the impinging jet flow. On the other hand, for the <span><math><mrow><mo>-</mo><mi>g</mi></mrow></math></span> condition, there was no vortex and no “flow separation phenomena” (Shekhar et al., 2014) and the fluid flow was at steady state. The <em>Nu</em> distribution was evaluated by the Richardson number, <em>Ri</em>. The average <em>Nu</em> increased slightly with + <em>Ri</em> for <span><math><mrow><mo>+</mo><mi>g</mi></mrow></math></span> while the average <em>Nu</em> decreased with −<em>Ri</em> for <span><math><mrow><mo>-</mo><mi>g</mi></mrow></math></span>. In these experimental conditions, there was a suitable condition for CVD for <span>-</span>240 < <em>Ri</em> < <span>-</span>160 whereby the deviation of the Nusselt number along the radial position on the heated substrate was less than 0.2. Time-dependent flow with a time period of 2.7 s was observed due to the collision of fresh hydrogen flow and buoyant upward flow on a heated disc at 0.05 < <em>S</em><sub>H</sub>/<em>S</em><sub>C</sub> (open area ratio of the hole to the cylindrical flow channel) < 0.1 and <em>Ri</em> < 100 for <span><math><mrow><mo>+</mo><mi>g</mi></mrow></math></span>.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110289"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170484","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}

引用次数: 0

Second law aerodynamic losses from symmetric turbine blades with and without film cooling 有和没有气膜冷却的对称涡轮叶片的第二定律气动损失

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-06 DOI: 10.1016/j.ijheatfluidflow.2026.110279

Phil Ligrani , Jae Sik Jin

Experimental results are presented which illustrate magnitudes of second law losses, including spatial-averaged global exergy destruction, which are a result of aerodynamic losses generated from a symmetric turbine blade with film cooling and without film cooling. The approach is unique and different because irreversibilities, which result from different physical phenomena, are presented on the same global exergy destruction basis, providing means for quantitative comparisons regarding relative second law loss contributions from different physical mechanisms. Film cooling results are provided for two configurations: CDH or conical diffused holes, and RCH or round cylindrical holes, with ratios of coolant Mach number to local mainstream Mach number as high as 0.74. Data are also included for three airfoil Mach number distributions (with two subsonic arrangements and one transonic arrangement), three values of turbulence intensity at the test section inlet (on a percentage basis) of 0.9, 5.5, and 16.2, and surfaces with three different levels of roughness, quantified by ratios of equivalent sandgrain roughness to blade chord length k_s/c of 0.0, 0.00069, and 0.00164. Relative to a smooth, symmetric blade at low freestream turbulence intensity and low Mach number, which is also without coolant films, the greatest increases in local entropy creation distributions and exergy destruction are associated with larger Mach numbers, and increased roughness along surfaces. Results also indicate that exergy destruction overall values and local entropy creation increases, which are associated with coolant films, are generally significantly smaller than magnitudes linked with larger roughness on blade surfaces. In addition, the dependences of overall exergy destruction magnitudes, and local entropy creation distributions, on main flow Mach number and inlet intensity of turbulence intensity, change significantly as the magnitude surface roughness along the symmetric turbine blade is altered.

实验结果说明了第二定律损失的大小，包括空间平均的整体火用破坏，这是由对称涡轮叶片产生的气动损失造成的，有气膜冷却和没有气膜冷却。该方法是独特而不同的，因为不同物理现象产生的不可逆性是在相同的全局火能破坏基础上呈现的，这为定量比较不同物理机制对相对第二定律损失的贡献提供了手段。给出了CDH（锥形扩散孔）和RCH（圆形圆柱孔）两种配置的气膜冷却结果，冷却剂马赫数与当地主流马赫数之比高达0.74。数据还包括三种翼型马赫数分布（两种亚音速布置和一种跨音速布置），试验段入口处的三种湍流强度值（按百分比计算）分别为0.9、5.5和16.2，以及三种不同粗糙度水平的表面，等效沙粒粗糙度与叶片弦长ks/c的比值分别为0.0、0.00069和0.00164。相对于在低自由流湍流强度和低马赫数条件下的光滑对称叶片（也没有冷却剂膜），局部熵创造分布和火用破坏的最大增加与马赫数的增大和表面粗糙度的增加有关。结果还表明，与冷却液膜相关的火用破坏总体值和局部熵创造增加值通常显著小于与叶片表面较大粗糙度相关的幅度。此外，总体火能破坏震级和局部熵创造分布对主流马赫数和进口湍流强度的依赖关系随着对称涡轮叶片震级表面粗糙度的改变而发生显著变化。

{"title":"Second law aerodynamic losses from symmetric turbine blades with and without film cooling","authors":"Phil Ligrani , Jae Sik Jin","doi":"10.1016/j.ijheatfluidflow.2026.110279","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110279","url":null,"abstract":"<div><div>Experimental results are presented which illustrate magnitudes of second law losses, including spatial-averaged global exergy destruction, which are a result of aerodynamic losses generated from a symmetric turbine blade with film cooling and without film cooling. The approach is unique and different because irreversibilities, which result from different physical phenomena, are presented on the same global exergy destruction basis, providing means for quantitative comparisons regarding relative second law loss contributions from different physical mechanisms. Film cooling results are provided for two configurations: CDH or conical diffused holes, and RCH or round cylindrical holes, with ratios of coolant Mach number to local mainstream Mach number as high as 0.74. Data are also included for three airfoil Mach number distributions (with two subsonic arrangements and one transonic arrangement), three values of turbulence intensity at the test section inlet (on a percentage basis) of 0.9, 5.5, and 16.2, and surfaces with three different levels of roughness, quantified by ratios of equivalent sandgrain roughness to blade chord length <em>k<sub>s</sub>/c</em> of 0.0, 0.00069, and 0.00164. Relative to a smooth, symmetric blade at low freestream turbulence intensity and low Mach number, which is also without coolant films, the greatest increases in local entropy creation distributions and exergy destruction are associated with larger Mach numbers, and increased roughness along surfaces. Results also indicate that exergy destruction overall values and local entropy creation increases, which are associated with coolant films, are generally significantly smaller than magnitudes linked with larger roughness on blade surfaces. In addition, the dependences of overall exergy destruction magnitudes, and local entropy creation distributions, on main flow Mach number and inlet intensity of turbulence intensity, change significantly as the magnitude surface roughness along the symmetric turbine blade is altered.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110279"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170483","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}

引用次数: 0

Topology optimization of microchannel heat sinks with different Inlet-outlet Widths: 2D optimization and 3D numerical validation 不同进出口宽度微通道散热器拓扑优化：二维优化与三维数值验证

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-01-27 DOI: 10.1016/j.ijheatfluidflow.2026.110277

Xiao-Mei Jin, Ji-Kai Shao, Zeng-Yao Li

Although received considerable attention in microchannel heat sinks of thermal management systems, current topology optimizations have primarily concentrate on enhancing the thermohydraulic performance through internal channel redesign while maintaining fixed inlet and outlet configurations. In this study, the 2D topology optimization of microchannel heat sinks with different inlet and outlet widths is investigated based on the variable density method, with the aim of maximizing the total heat generation and minimizing the total power consumption. The influences of thermal objective weights and Reynolds numbers on topology optimization results are explored in detail. Meanwhile, the 3D numerical simulation is performed to validate the 2D optimized topology. It is demonstrated that the optimized Z-type flow arrangement microchannel heat sink with inlet and outlet both having half the width of the design domain can substantially enhance the thermohydraulic performance, and achieve a 46.4–62.2% reduction in pumping power with the lowest temperature of the bottom wall, compared to the conventional one.

尽管在热管理系统的微通道散热器中受到了相当大的关注，但目前的拓扑优化主要集中在通过重新设计内部通道来提高热水力性能，同时保持固定的入口和出口配置。本研究以总发热量最大化和总功耗最小化为目标，基于变密度方法，研究了不同进出口宽度微通道散热器的二维拓扑优化问题。详细探讨了热目标权值和雷诺数对拓扑优化结果的影响。同时，进行了三维数值仿真，验证了优化后的二维拓扑结构。结果表明，优化后的入口和出口宽度均为设计区域宽度的一半的z型流场微通道散热器，可以显著提高热液性能，在底壁温度最低的情况下，泵送功率比常规散热器降低46.4 ~ 62.2%。

{"title":"Topology optimization of microchannel heat sinks with different Inlet-outlet Widths: 2D optimization and 3D numerical validation","authors":"Xiao-Mei Jin, Ji-Kai Shao, Zeng-Yao Li","doi":"10.1016/j.ijheatfluidflow.2026.110277","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110277","url":null,"abstract":"<div><div>Although received considerable attention in microchannel heat sinks of thermal management systems, current topology optimizations have primarily concentrate on enhancing the thermohydraulic performance through internal channel redesign while maintaining fixed inlet and outlet configurations. In this study, the 2D topology optimization of microchannel heat sinks with different inlet and outlet widths is investigated based on the variable density method, with the aim of maximizing the total heat generation and minimizing the total power consumption. The influences of thermal objective weights and Reynolds numbers on topology optimization results are explored in detail. Meanwhile, the 3D numerical simulation is performed to validate the 2D optimized topology. It is demonstrated that the optimized Z-type flow arrangement microchannel heat sink with inlet and outlet both having half the width of the design domain can substantially enhance the thermohydraulic performance, and achieve a 46.4–62.2% reduction in pumping power with the lowest temperature of the bottom wall, compared to the conventional one.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110277"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074266","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}

引用次数: 0

Stray grain suppression and stress control in single-crystal superalloys fabricated by L-DED: A multiphysics analysis of in-situ remelting L-DED单晶高温合金的杂散晶粒抑制和应力控制：原位重熔的多物理场分析

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-02 DOI: 10.1016/j.ijheatfluidflow.2026.110283

Gengshuo Liu , Shujie Liu , Haonan Cong , Weiwei Liu , Tao Li , Yu Wang , Tinghong Hou

Laser-Directed Energy Deposition (L-DED) has been demonstrated as a promising pathway for fabricating single-crystal superalloys. However, achieving single track multilayer continuous epitaxial growth remains a formidable challenge due to the complex gas-powder-melt pool multiphase interactions. Existing approaches are often hindered by stray grain formation due to the presence of un-melted powder particles and the complexity thermal histories processes. Moreover, the excessively high computational cost of high-fidelity multiphysics simulations restricts the swift optimization of the process window. To overcome these challenges, this research demonstrates the application of in-situ remelting (ISR) technology in the single-crystal superalloys. By developing a dedicated laser-powder interaction model and a thermal-fluid–solid coupling model, we systematically reveal the regulatory mechanisms of in-situ remelting on thermal gradients, flow characteristics, and stress evolution during single-crystal superalloys fabricate. To address the efficiency bottleneck, a surrogate model based on deep neural networks (ResNet) was developed for the L-DED multi-physics simulation. Key findings demonstrate that the proposed strategy: 1) Eliminates un-melted powder particles interference and optimizes thermal gradients, increasing the single-crystal epitaxial growth zone ratio to over 50 %; 2) Suppresses flow field intensity (>70 % reduction) and vortex effects, thereby mitigating stray grain susceptibility induced by dendrite deflection; and 3) Reduces residual stress in deposited layers by over 25 %, effectively inhibiting high-layer cracking risks. Through this integrated analysis, we establish a robust L-DED process window incorporating flow/stress constraints and achieve the continuous epitaxial growth of a 20-layer DD432 single-crystal superalloy, validated by EBSD.

激光定向能量沉积（L-DED）已被证明是制备单晶高温合金的一种很有前途的途径。然而，由于复杂的气体-粉末-熔池多相相互作用，实现单轨多层连续外延生长仍然是一个巨大的挑战。由于存在未熔化的粉末颗粒和复杂的热历史过程，现有的方法经常受到杂散颗粒形成的阻碍。此外，高保真多物理场模拟的计算成本过高，限制了过程窗口的快速优化。为了克服这些挑战，本研究展示了原位重熔（ISR）技术在单晶高温合金中的应用。通过建立专用的激光-粉末相互作用模型和热-流-固耦合模型，系统地揭示了原位重熔对单晶高温合金制备过程中热梯度、流动特性和应力演化的调节机制。为了解决效率瓶颈问题，开发了基于深度神经网络（ResNet）的L-DED多物理场仿真代理模型。主要研究结果表明：1)消除未熔化粉末颗粒的干扰，优化热梯度，使单晶外延生长区比提高到50%以上；2)抑制流场强度（降低70%）和涡流效应，从而减轻枝晶偏转引起的杂散晶粒敏感性；3)降低堆积层残余应力25%以上，有效抑制高层开裂风险。通过这一综合分析，我们建立了一个包含流动/应力约束的稳健的L-DED工艺窗口，并实现了20层DD432单晶高温合金的连续外延生长，并通过EBSD进行了验证。

{"title":"Stray grain suppression and stress control in single-crystal superalloys fabricated by L-DED: A multiphysics analysis of in-situ remelting","authors":"Gengshuo Liu , Shujie Liu , Haonan Cong , Weiwei Liu , Tao Li , Yu Wang , Tinghong Hou","doi":"10.1016/j.ijheatfluidflow.2026.110283","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110283","url":null,"abstract":"<div><div>Laser-Directed Energy Deposition (L-DED) has been demonstrated as a promising pathway for fabricating single-crystal superalloys. However, achieving single track multilayer continuous epitaxial growth remains a formidable challenge due to the complex gas-powder-melt pool multiphase interactions. Existing approaches are often hindered by stray grain formation due to the presence of un-melted powder particles and the complexity thermal histories processes. Moreover, the excessively high computational cost of high-fidelity multiphysics simulations restricts the swift optimization of the process window. To overcome these challenges, this research demonstrates the application of in-situ remelting (ISR) technology in the single-crystal superalloys. By developing a dedicated laser-powder interaction model and a thermal-fluid–solid coupling model, we systematically reveal the regulatory mechanisms of in-situ remelting on thermal gradients, flow characteristics, and stress evolution during single-crystal superalloys fabricate. To address the efficiency bottleneck, a surrogate model based on deep neural networks (ResNet) was developed for the L-DED multi-physics simulation. Key findings demonstrate that the proposed strategy: 1) Eliminates un-melted powder particles interference and optimizes thermal gradients, increasing the single-crystal epitaxial growth zone ratio to over 50 %; 2) Suppresses flow field intensity (>70 % reduction) and vortex effects, thereby mitigating stray grain susceptibility induced by dendrite deflection; and 3) Reduces residual stress in deposited layers by over 25 %, effectively inhibiting high-layer cracking risks. Through this integrated analysis, we establish a robust L-DED process window incorporating flow/stress constraints and achieve the continuous epitaxial growth of a 20-layer DD432 single-crystal superalloy, validated by EBSD.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110283"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146169961","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}

引用次数: 0

An elliptic-blending-related upgrade of a near-wall Reynolds-stress model 近壁雷诺应力模型的椭圆混合相关升级

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow

Pub Date : 2026-04-01 Epub Date: 2026-02-01 DOI: 10.1016/j.ijheatfluidflow.2026.110285

Sebastian Wegt , Robert Maduta , Suad Jakirlić

A new version of the near-wall Reynolds-stress

\bar{u_{i} u_{j}} - ω^{h}

model by Jakirlić and Maduta (2015), based on the pressure–strain model term derived in accordance with the elliptic-blending procedure introduced by Manceau and Hanjalić (2002), is proposed. Accordingly, a quadratic formulation modeled in terms of Reynolds-stress anisotropy tensor, as proposed by Speziale et al. (1991), that is active in the off-wall region, is blended with an appropriately specified wall-related counterpart satisfying the exact asymptotic behavior. This blending approach eliminates the necessity to express model coefficients as complex functional dependencies, allowing them instead to be specified as constants. A further modeling refinement of importance involves the use of an appropriately modified turbulent diffusion coefficient in both the Reynolds-stress and scale-supplying equations, thereby removing the need for additional, often ad hoc, source terms typically introduced to address the well-known anomaly of the back-bending of the mean dividing streamline at the reattachment point in separating flows. The computational robustness of the model is significantly enhanced by including a specific form of coupling between the velocity and Reynolds-stress fields in the RANS (Reynolds-Averaged Navier–Stokes) equations of motion. In this formulation, a small, variably designed percentage of the Reynolds stress derived from Boussinesq’s correlation is retained. The model is thoroughly validated in various attached and separated, two-dimensional and three-dimensional flow configurations over a range of Reynolds numbers. The results obtained exhibit a high level of agreement with available experimental measurements and reference data from DNS (Direct Numerical Simulation) and LES (Large-Eddy Simulation).

基于基于Manceau和hanjaliki（2002）引入的椭圆混合过程导出的压力-应变模型项，提出了jakirliki和Maduta（2015）的近壁Reynolds-stress uij¯−ωh模型的新版本。因此，Speziale等人（1991）提出的以雷诺兹应力各向异性张量（Reynolds-stress anisotropy tensor）为模型的二次公式在离壁区域活跃，与满足精确渐近行为的适当指定的壁相关对应项混合。这种混合方法消除了将模型系数表示为复杂的功能依赖的必要性，而是允许将它们指定为常量。进一步的建模细化涉及在雷诺应力和尺度供应方程中使用适当修改的湍流扩散系数，从而消除了对额外的，通常是特别的源项的需要，这些源项通常是为了解决众所周知的分离流中在再附点处平均划分流线的反向弯曲异常而引入的。通过在RANS （reynolds - average Navier-Stokes）运动方程中加入速度和reynolds -应力场之间的特定耦合形式，该模型的计算鲁棒性得到了显著提高。在这个公式中，一个小的，可变设计百分比的雷诺应力源自布辛涅斯克的相关被保留。该模型在雷诺数范围内的各种附加和分离、二维和三维流动配置中得到了彻底的验证。所得结果与现有实验测量和直接数值模拟（DNS）和大涡模拟（LES）的参考数据高度一致。

{"title":"An elliptic-blending-related upgrade of a near-wall Reynolds-stress model","authors":"Sebastian Wegt , Robert Maduta , Suad Jakirlić","doi":"10.1016/j.ijheatfluidflow.2026.110285","DOIUrl":"10.1016/j.ijheatfluidflow.2026.110285","url":null,"abstract":"<div><div>A new version of the near-wall Reynolds-stress <span><math><mrow><mover><mrow><msub><mrow><mi>u</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>u</mi></mrow><mrow><mi>j</mi></mrow></msub></mrow><mo>¯</mo></mover><mo>−</mo><msup><mrow><mi>ω</mi></mrow><mrow><mi>h</mi></mrow></msup></mrow></math></span> model by Jakirlić and Maduta (2015), based on the pressure–strain model term derived in accordance with the elliptic-blending procedure introduced by Manceau and Hanjalić (2002), is proposed. Accordingly, a quadratic formulation modeled in terms of Reynolds-stress anisotropy tensor, as proposed by Speziale et al. (1991), that is active in the off-wall region, is blended with an appropriately specified wall-related counterpart satisfying the exact asymptotic behavior. This blending approach eliminates the necessity to express model coefficients as complex functional dependencies, allowing them instead to be specified as constants. A further modeling refinement of importance involves the use of an appropriately modified turbulent diffusion coefficient in both the Reynolds-stress and scale-supplying equations, thereby removing the need for additional, often ad hoc, source terms typically introduced to address the well-known anomaly of the back-bending of the mean dividing streamline at the reattachment point in separating flows. The computational robustness of the model is significantly enhanced by including a specific form of coupling between the velocity and Reynolds-stress fields in the RANS (Reynolds-Averaged Navier–Stokes) equations of motion. In this formulation, a small, variably designed percentage of the Reynolds stress derived from Boussinesq’s correlation is retained. The model is thoroughly validated in various attached and separated, two-dimensional and three-dimensional flow configurations over a range of Reynolds numbers. The results obtained exhibit a high level of agreement with available experimental measurements and reference data from DNS (Direct Numerical Simulation) and LES (Large-Eddy Simulation).</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"119 ","pages":"Article 110285"},"PeriodicalIF":2.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146169967","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}

引用次数: 0