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。

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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。

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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。

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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。

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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。

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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。

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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。

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引用次数: 0

Numerical investigations of jet A–hexane binary fuel droplet impact on a heated solid surface 射流a -己烷二元燃料液滴撞击加热固体表面的数值研究

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: 2026-01-07 DOI: 10.1016/j.ijheatfluidflow.2025.110223

Arghya Paul, Kanak Raj, Pratim Kumar

In the present work, the numerical study of Jet A Hexane-based binary fuel droplet impact dynamics on heated solid surfaces was conducted. This study is crucial for practical applications such as fuel injection in combustors and thermal management of engine components. The volume of fluid (VOF) method was used to analyse the impact dynamics, spreading behaviour, vaporisation, and heat transfer of n-hexane and Jet-A blended fuel droplets on heated stainless-steel surfaces. Droplet impact dynamics were investigated for two Weber numbers, i.e., 25 and 50, and surface temperatures ranging from 50 °C to 227 °C to capture transitions from gentle spreading to nucleate boiling and rebound phenomena. This work examines how fuel blending influences inertia, lamella formation, vapour recoil, and film boiling regimes. The results show that higher inertia in blended fuels enhances spreading but also triggers stronger vapour recoil at elevated temperatures, leading to droplet rebound. In contrast, pure hexane transitions to a stable film boiling regime at high surface temperatures, resulting in smoother heat flux decline. New correlations were developed linking Weber number, spreading ratio, and wall heat flux, offering predictive insights for real-world combustion scenarios. These findings advance the understanding of bi-component fuel droplet impacts on heated surfaces and provide a framework for designing efficient spray systems in combustors and thermal management in propulsion and power generation applications.

本文对Jet A型二元燃料液滴在加热固体表面上的碰撞动力学进行了数值研究。该研究对实际应用具有重要意义，如燃烧室燃油喷射和发动机部件的热管理。采用流体体积法（VOF）分析了正己烷和Jet-A混合燃料液滴在加热不锈钢表面上的冲击动力学、扩散行为、汽化和传热。研究了两个韦伯数（25和50）和表面温度（50 ~ 227℃）下液滴撞击动力学，以捕捉从温和扩散到成核沸腾和反弹现象的转变。这项工作考察了燃料混合如何影响惯性、薄片形成、蒸汽反冲和薄膜沸腾制度。结果表明，混合燃料中较大的惯性增强了扩散，但在高温下也引发了更强的蒸气反冲，导致液滴反弹。相比之下，纯己烷在高表面温度下转变为稳定的膜沸腾状态，导致热通量下降更平稳。研究人员开发了韦伯数、扩散比和壁面热流密度之间的新相关性，为实际燃烧场景提供了预测性见解。这些发现促进了对双组分燃料液滴在受热表面上的影响的理解，并为在燃烧器中设计有效的喷雾系统以及在推进和发电应用中的热管理提供了一个框架。

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引用次数: 0

Mass transfer to a stationary electrode in an insulating plane under oscillatory flow linear and nonlinear behaviors 在振荡流动的线性和非线性行为下，绝缘平面内固定电极的传质

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.2026.110295

Brahim Addou , Ben-Richou Abderrahim , Balouki Abdessamad , Azouz Jaouad

This study presents a detailed numerical investigation of unsteady mass transfer in a confined shear flow subjected to periodic modulation of wall shear stress. A dedicated finite-volume solver was developed to solve the unsteady convection diffusion equation, explicitly accounting for axial diffusion and time-dependent wall-shear conditions. Simulations were performed over a wide range of Peclet numbers (

1 0^{- 2} \leq Pe \leq 1 0^{6}

), excitation frequencies, and modulation amplitudes (

0.01 \leq A_{0} \leq 10

), enabling a systematic exploration of both linear and nonlinear response behaviors. The novelty of this work lies in the direct numerical determination of the diffusion-layer transfer function and in the introduction of a unified frequency-domain framework linking linear and nonlinear behaviors. This approach provides a consistent methodology for identifying the linear transfer function while tracking the onset and evolution of nonlinearities as the wall-shear modulation amplitude increases.

Spectral analysis of the unsteady mass flux, performed using Fourier transform techniques, reveals the emergence of harmonic components, highlighting the nonlinear filtering properties of the diffusion layer. Comparisons with the classical Lévêque asymptotic solution confirm that, at low frequencies and large amplitudes, strong convective enhancement occurs (

THD ≫ 100 %

), whereas at higher reduced frequencies, the system exhibits a quasi-linear response typical of a low-pass filter, with minimal harmonic content (

THD < 10 %

). The proposed framework constitutes a robust and generalizable tool for analyzing unsteady convective-diffusive and electrochemical transport phenomena in dynamically actuated systems.

本文对受壁面剪切应力周期性调节的受限剪切流中的非定常传质问题进行了详细的数值研究。开发了一个专用的有限体积求解器来求解非定常对流扩散方程，明确地考虑了轴向扩散和随时间变化的壁面剪切条件。模拟在Peclet数（10−2≤Pe≤106）、激励频率和调制幅度（0.01≤A0≤10）的广泛范围内进行，从而能够系统地探索线性和非线性响应行为。这项工作的新颖之处在于直接数值确定扩散层传递函数，并引入了连接线性和非线性行为的统一频域框架。这种方法提供了一种一致的方法来识别线性传递函数，同时跟踪随着壁剪力调制幅度的增加非线性的开始和演变。利用傅里叶变换技术对非定常质量通量进行频谱分析，揭示了谐波分量的出现，突出了扩散层的非线性滤波特性。与经典的Lévêque渐近解的比较证实，在低频率和大振幅下，系统出现强对流增强（THD > 100%），而在更高的降频下，系统表现出典型的低通滤波器的准线性响应，谐波含量最小（THD<10%）。所提出的框架为分析动态驱动系统中的非定常对流扩散和电化学输运现象提供了一个强大的、可推广的工具。

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引用次数: 0

Hydrothermal performance analysis of microchannel heat sink with novel aircraft-shaped varied-section ribs 新型飞机形变截面肋微通道散热器热液性能分析

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: 2026-02-10 DOI: 10.1016/j.ijheatfluidflow.2026.110298

Hongxin Deng , Guilian Wang , Chunyan Zhao , Dongdong Xie

The hydrothermal performance of the microchannel heat sink with novel aircraft-shaped varied-section ribs (AVSRs) is numerically investigated in the present paper. The AVSR has two distinctive structural features: a streamlined bulge surface and a curved back end. The streamlined bulge surface can induce a remarkable impingement effect in the microchannel, and the curved back end promotes the formation of recirculation in both vertical and horizontal directions. These combine to promote significant convective heat transfer, which improves the cooling efficiency of the heat sink. The AVSR is compared with two rectangular ribs: one has the same length and height as the AVSR (LHR), and the other possesses the same volume (VOR). The microchannel with AVSRs (MC-AVSR) presents an increment of 10.56–61.20 % in Nusselt number (Nu) compared to the smooth microchannel (MC-SC). Meanwhile, the MC-AVSR reveals the implementation of 4.30–45.01 % and 5.39–24.58 % in Nu compared with the microchannel with LHRs (MC-LHR) and VORs (MC-VOR), respectively. Moreover, the apparent friction factor of MC-AVSR is reduced by 1.72–13.92 % and 2.10–3.95 % in comparison with those of MC-LHR and MC-VOR, respectively. These demonstrate that the AVSRs more effectively enhance the thermal performance and also produce less blockage to fluid flow. Moreover, the thermal enhancement factor of MC-AVSR remains larger than 1, indicating that the promoted heat transfer effectiveness consistently offsets the pressure drop penalty induced by the AVSRs.

本文对新型飞机形变截面肋微通道热沉的热液性能进行了数值研究。AVSR有两个独特的结构特征：流线型凸起表面和弯曲的后端。流线型凸起面在微通道内产生显著的冲击效应，弯曲的后端促进了垂直和水平方向再循环的形成。这些结合起来促进显著的对流传热，从而提高了散热器的冷却效率。将AVSR比作两个矩形肋：一个具有与AVSR相同的长度和高度（LHR），另一个具有相同的体积（VOR）。与光滑微通道（MC-SC）相比，带avsr微通道（MC-AVSR）的努塞尔数（Nu）增加了10.56 ~ 61.20%。与lhr （MC-LHR）和VORs （MC-VOR）微通道相比，MC-AVSR在Nu中的实现率分别为4.30 - 45.01%和5.39 - 24.58%。与MC-LHR和MC-VOR相比，MC-AVSR的表观摩擦系数分别降低了1.72 ~ 13.92%和2.10 ~ 3.95%。这些结果表明，avsr能更有效地提高热学性能，并且对流体流动产生更小的阻塞。此外，MC-AVSR的热增强系数仍然大于1，表明其提升的传热效率始终抵消了avsr引起的压降损失。

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引用次数: 0