Case Studies in Thermal Engineering最新文献_第5页

Structural optimization of multi-heat-source cold plates using neural network and genetic algorithm 基于神经网络和遗传算法的多热源冷板结构优化

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-27 DOI: 10.1016/j.csite.2026.107851

Yifei Zhang, Yubin Zhuang, Pan Cui, Wei Liu, Zhichun Liu

This study proposes an integrated framework coupling neural networks with the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) for the independent multi-zone optimization of fin structures in both straight-fin and hybrid-fin cold plates, addressing the thermal management challenge of multi-heat-source configurations. The framework systematically investigates how zonal fin parameters regulate thermo-hydraulic performance, with optimization conducted under two distinct objectives. Results vs. the initial design show: minimum-pressure-drop designs cut flow resistance by 47.4% (straight-fin) and 52.9% (hybrid-fin), while balanced designs reduced it by 28% and 38.4% respectively, with improved temperature uniformity. Direct comparison with traditional global optimization (uniform fin parameters) shows the traditional method only cut flow resistance by 19.3%, versus 34.9–41.7% for ours, plus targeted thermal management unavailable to uniform designs. Hybrid-fin designs exhibit superior overall performance, particularly in zone R2 (high-power devices), enhancing heat dissipation without hydraulic compromise. Mechanistic analysis reveals outlet zone (R1) parameters dominate pressure drop due to local resistance losses, inlet zone (R3) is sensitive to downstream undeveloped flow, and intermediate zone (R2) behaves thermally independently with fully developed flow. Fin count modulates convective intensity via area-velocity effects, while fin thickness regulates thermal conduction and uniformity. This zonal control methodology cuts pumping power while ensuring thermal safety for uneven heat sources. The framework provides scalable optimization for multi-heat-source cold plates, enabling flexible strategy formulation per application-specific thermo-hydraulic priorities.

为了解决多热源配置下的热管理难题，本研究提出了一种将神经网络与非支配排序遗传算法II （NSGA-II）相结合的集成框架，用于直鳍和混合鳍冷板翅片结构的独立多区域优化。该框架系统地研究了区域翅片参数如何调节热工性能，并在两个不同的目标下进行了优化。与初始设计相比，结果表明：最小压降设计降低了47.4%（直鳍）和52.9%（混合鳍）的流动阻力，而平衡设计分别降低了28%和38.4%，并改善了温度均匀性。与传统的全局优化（均匀翅片参数）直接比较表明，传统方法只能降低19.3%的流动阻力，而我们的方法可以降低34.9-41.7%，而且均匀设计无法实现有针对性的热管理。混合鳍设计表现出卓越的整体性能，特别是在R2区（大功率设备），在不损害液压的情况下增强散热。机理分析表明，由于局部阻力损失，出口区（R1）参数对压降起主导作用，进口区（R3）对下游不发达流动敏感，中间区（R2）在流动完全发达时表现为热独立。翅片数量通过面积-速度效应调节对流强度，而翅片厚度调节热传导和均匀性。这种分区控制方法减少了泵送功率，同时确保了不均匀热源的热安全。该框架为多热源冷板提供了可扩展的优化，使每个应用特定的热液压优先级的灵活策略制定成为可能。

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引用次数: 0

Multi-objective optimization of burner configurations in sintering ignition furnace: A CFD-based orthogonal test with matrix analysis 烧结炉燃烧器配置的多目标优化：基于cfd的正交试验与矩阵分析

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-03-04 DOI: 10.1016/j.csite.2026.107908

Zhengzong Huang , Jingfan Chen , Xia Wu, Zongya Wang, Dongling Wu, Liu Liu, Hongjie Yan

To achieve a comprehensive parameter optimization scheme for the sintering ignition furnace that facilitates energy conservation and productivity improvement, multi-objective optimization research on the burner configurations has been implemented by using computational fluid dynamics. An L₉(3³) orthogonal test was designed to focus on three key burner configuration parameters: ignition burner inclination angle, main burner airflow area, and main burner arrangement. Based on the range and matrix analyses, the orthogonal test results are meticulously analyzed, culminating in the identification of the optimal scheme. The optimization benefits are demonstrated through comparative analysis. Results indicate that the main burner arrangement affects the ignition quality most significantly, followed by the ignition burner inclination angle, with the main burner airflow area having the least impact. The optimal configuration includes setting the ignition burner inclination angle at 15°, the main burner airflow area at 1540 mm², and a “7 + 7″ uniform arrangement for the main burner. The flow field stability enhances markedly; the flame jet rigidity increases substantially; the burner jets mutual interference diminishes notably; the temperature field in the ignition section improves significantly. Compared to the baseline case, the average temperature in the ignition section increases by 40 K, while the temperature uniformity coefficient decreases by 4.99%.

为了获得有利于节能和提高生产率的烧结点火炉综合参数优化方案，运用计算流体力学方法对燃烧器配置进行了多目标优化研究。设计了L9（33）正交试验，重点研究了点火燃烧器倾角、主燃烧器气流面积和主燃烧器布置这三个关键燃烧器配置参数。在极差分析和矩阵分析的基础上，对正交试验结果进行了细致的分析，最终确定了最优方案。通过对比分析，论证了优化的效益。结果表明：主燃烧器布置对点火质量的影响最显著，其次是点火燃烧器倾角，主燃烧器气流面积对点火质量的影响最小；最佳配置包括点火燃烧器倾角设置为15°，主燃烧器气流面积为1540 mm2，主燃烧器为“7 + 7″”均匀布置。流场稳定性显著增强；火焰射流刚度大幅度提高；燃烧器射流相互干扰显著减小；点火段温度场明显改善。与基准情况相比，点火段平均温度提高了40 K，温度均匀性系数降低了4.99%。

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引用次数: 0

Thermodynamic and thermoeconomic analysis of an intercooled regenerative reheat gas turbine cogeneration system: A case study for Côte d’Ivoire, West Africa 中冷蓄热式再热燃气轮机热电联产系统的热力学和热经济分析：以Côte科特迪瓦为例，西非

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-03-02 DOI: 10.1016/j.csite.2026.107892

Kousso Karell Kevine Andoh , Ali Husnu Bademlioglu

In this study, the gas turbine cogeneration system planned to be established in Côte d’Ivoire, West Africa was modeled and the thermodynamic and thermoeconomic performance of the system was investigated. Energy, exergy, and economic analyses were conducted for the system, which consists of an intercooled regenerative reheat (IRR) gas turbine cycle and an absorption refrigeration cycle (ARC), for various operating parameters. Within the scope of the study, the effects of pressure ratio (8–16), compressor isentropic efficiency (80–88%), turbine isentropic efficiency (75–85%), generator temperature (90–100 °C), and evaporator temperature (0–5 °C) on system performance were evaluated, and accordingly, the energy utilization factor (EUF), levelized cost of electricity (LCOE), and levelized cost of cooling (LCOC) were determined. Additionally, the analyses were conducted under different ambient temperature conditions to evaluate the system's performance under typical temperature scenarios observed in Côte d’Ivoire. Depending on the investigated parameter ranges, the energy efficiency of the IRR gas turbine varied between 35.17 and 42.72%, while the exergy efficiency ranged from 35.85 to 44.05%. In addition, the EUF of the IRR gas turbine cogeneration system varied between 60.43 and 63.30%, whereas the LCOE and LCOC ranged from 0.02527 to 0.04682 USD/kWh and 0.04839–0.07054 USD/kWh, respectively. Overall, the results highlight that the investigated operating parameters significantly affect the thermodynamic and thermoeconomic performance of the proposed IRR gas turbine cogeneration system.

本研究对拟在西非科特迪瓦Côte建立的燃气轮机热电联产系统进行了建模，并对该系统的热力学和热经济性能进行了研究。对该系统进行了能量、火用和经济分析，该系统包括一个中冷再生再热（IRR）燃气轮机循环和一个吸收式制冷循环（ARC），用于各种运行参数。在研究范围内，评估了压力比（8-16）、压缩机等熵效率（80-88%）、涡轮等熵效率（75-85%）、发电机温度（90-100℃）和蒸发器温度（0-5℃）对系统性能的影响，并据此确定了能量利用系数（EUF）、平准化电力成本（LCOE）和平准化冷却成本（LCOC）。此外，还在不同的环境温度条件下进行了分析，以评估系统在Côte d ' ivivire观察到的典型温度情景下的性能。根据所研究的参数范围，IRR燃气轮机的能量效率在35.17 ~ 42.72%之间，火用效率在35.85 ~ 44.05%之间。此外，IRR燃机热电联产系统的EUF在60.43 ~ 63.30%之间，LCOE和LCOC分别在0.02527 ~ 0.04682美元/千瓦时和0.04839 ~ 0.07054美元/千瓦时之间。总体而言，研究结果表明，所研究的运行参数对所提出的IRR燃气轮机热电联产系统的热力学和热经济性能有显著影响。

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引用次数: 0

Synergistic effects of palm oil and cordierite partial-flow particulate filter on thermal efficiency and emission characteristics of a 2.5L diesel vehicle 棕榈油和堇青石颗粒过滤器对2.5L柴油车热效率和排放特性的协同效应

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-03-05 DOI: 10.1016/j.csite.2026.107911

Huy Quang Dang , Mek Srilomsak , Preechar Karin , Sompong Srimanosaowapak , Vitoon Uthaisangsuk , Chinda Charoenphonphanich

This study experimentally evaluates the synergistic effects of palm oil biodiesel fuels and a cordierite-based partial-flow diesel particulate filter (P-DPF) on the thermal efficiency and emission characteristics of a 2.5L light-duty diesel vehicle, using commercial fuels (B7 and B10) and neat biodiesel (B100). Steady-state chassis dynamometer tests showed that P-DPF installation increased exhaust backpressure by up to 7.2 kPa while causing only minor changes in fuel consumption and brake thermal efficiency. Under the New European Driving Cycle, B100 inherently reduced particulate number (PN) and mass (PM) by more than 43% and 32%, respectively, compared to commercial fuels. The integration of the P-DPF further reduced PN by 36–40% and PM by 57–60%. In addition, catalytic oxidation decreased CO and THC emissions by up to 20–25%, while NOx emissions were reduced by up to 20%, likely due to the combined effects of biodiesel properties and mild internal EGR induced by increased backpressure. Despite these improvements, the combined application remained insufficient to meet the Euro 5 limit but supported partial compliance with Euro 4 standards. These results demonstrate a practical and cost-effective retrofit strategy for reducing emissions from aging diesel vehicles.

本研究实验评估了棕榈油生物柴油燃料和堇青石基部分流柴油颗粒过滤器（P-DPF）对2.5L轻型柴油车的热效率和排放特性的协同效应，使用商用燃料（B7和B10）和纯生物柴油（B100）。稳态底盘测力仪测试表明，安装P-DPF后，排气背压增加了7.2千帕，而燃油消耗和制动热效率仅发生了微小变化。在新欧洲驾驶循环下，与商业燃料相比，B100本质上分别减少了43%和32%以上的颗粒数（PN）和质量（PM）。P-DPF的整合进一步降低了PN 36-40%和PM 57-60%。此外，催化氧化使CO和THC排放量减少了20-25%，而氮氧化物排放量减少了20%，这可能是由于生物柴油特性和背压增加引起的轻度内部EGR的综合作用。尽管有了这些改进，综合应用仍然不足以满足欧5的限制，但支持部分符合欧4标准。这些结果证明了一种实用且具有成本效益的改造策略，可以减少老化柴油车辆的排放。

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引用次数: 0

A comprehensive performance evaluation of a fuel-cell hybrid electric heavy-duty truck through energy flow experiment under user-defined driving test cycles 基于自定义驾驶工况下能量流实验的燃料电池混合动力重型卡车综合性能评价

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-10 DOI: 10.1016/j.csite.2026.107819

Renhua Feng , Zhanye Hua , Zhichao Zhao , Faguang Li , Xing Shu , Licheng Luo , Huikai Zhai

This study experimentally investigates the energy flow characteristics of a fuel cell (FC) hybrid electric heavy-duty truck under user-defined driving cycles. The analysis comprehensively examines three critical aspects including energy consumption distribution patterns, efficiency metrics of key powertrain components, and thermal management system performance. The results show that the FC stack achieves 47.98% conversion efficiency but suffers 49.6% thermal losses through coolant systems with power fluctuations, resulting in only 38.99% of initial energy reaching the wheels after accounting for losses in power electronics, transmission and auxiliary systems. The power battery effectively balances loads but achieves only 26.1% energy recovery during deceleration and motor efficiency drops below 85% during medium-speed and low-torque operation in intermediate gears, indicating optimization potential for both energy recovery and shift strategies. Thermal management challenges emerge throughout the system with FC coolant temperature variations correlating with current changes while maintaining 10 °C differentials during load fluctuations. Under the current cooling configuration, the maximum temperature of the battery cell rose to 35 °C. Meanwhile, the motor temperature increased from 27 °C to 50 °C and then stabilized at 45-50 °C. Although the system achieved basic thermal management, there are limitations in handling the heat load at the battery end, indicating the need to further improve the cooling design by increasing cooling capacity or optimizing algorithms. Additionally, the 2-4 °C cabin temperature variations and compressor instability highlight heating, ventilation and air conditioning system needs for outlet redesign or control strategies enhancements. This study constructed a brand-new energy flow analysis framework for FCHE, which not only quantifies energy consumption distribution and powertrain component efficiency, but also conducts in-depth analysis of the thermal management system from multiple dimensions such as temperature response, heat loss mechanism, and subsystem coordination. This research also provides a reference for the subsequent improvement of the performance and engineering application of FC hybrid heavy-duty trucks.

实验研究了燃料电池（FC）混合动力重型卡车在自定义行驶循环下的能量流特性。该分析全面考察了三个关键方面，包括能源消耗分布模式、关键动力总成组件的效率指标和热管理系统性能。结果表明，FC堆的转换效率为47.98%，但由于功率波动导致冷却剂系统的热损失为49.6%，考虑到电力电子、传动和辅助系统的损失，只有38.99%的初始能量到达车轮。动力电池可以有效平衡负载，但在减速时能量回收率仅为26.1%，在中档中速低转矩运行时电机效率降至85%以下，表明能量回收和换挡策略都有优化潜力。在整个系统中，随着电流变化，FC冷却剂温度变化，同时在负载波动期间保持10°C的差异，从而出现了热管理挑战。在当前冷却配置下，电池单体最高温度可达35℃。同时，电机温度从27℃升高到50℃，然后稳定在45-50℃。虽然该系统实现了基本的热管理，但在处理电池端热负荷方面存在局限性，表明需要通过增加冷却能力或优化算法来进一步改进冷却设计。此外，2-4°C的客舱温度变化和压缩机不稳定突出了加热、通风和空调系统需要重新设计出口或增强控制策略。本研究构建了全新的FCHE能量流分析框架，不仅量化了FCHE的能耗分布和动力总成组件效率，还从温度响应、热损失机理、子系统协调等多个维度对FCHE热管理系统进行了深入分析。本研究也为后续FC混合动力重卡的性能提升和工程应用提供了参考。

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引用次数: 0

Aerodynamic loading of lightweight green roof systems on industrial buildings: A case-based CFD study of an existing industrial hall 工业建筑轻型绿色屋顶系统的气动载荷：基于某既有工业厂房的CFD实例研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-21 DOI: 10.1016/j.csite.2026.107842

Pavel Kučírek , Ondřej Šikula , Michal Krajčík , Martin Mohapl , Müslüm Arıcı

Large low-rise industrial halls offer extensive roof areas for adding vegetated roof assemblies (VRAs) as part of reconstruction. However, existing structures often require lightweight VRAs to avoid overloading. To assess the wind resistance of such lightweight systems, atmospheric boundary layer simulations were conducted in OpenFOAM using Reynolds-Averaged Navier-Stokes approach for a cuboid industrial hall in a low-density built environment, representative of many industrial facilities worldwide. Additional roof geometries and adjoining-building cases were analysed to cover configurations not addressed in prior studies. Compared with a simple cuboid, a combined cuboid-bevel geometry experienced notably higher roof underpressure. The presence of an adjoining building further intensified corner-zone suction, increasing peak local suction from −608 Pa to −830 Pa (37%). For an extreme air velocity of 43.1 m/s recorded at the Brno (Czech Republic) meteorological station, the computed pressures were compared with the European standard for wind actions on structures. The peak suction reached approximately −4 kPa at the roof corner for a 45° wind direction, about twice the allowable limit for components with effective area ≤1 m², indicating that perpendicular-wind (0°) analyses may underestimate the risk for modular systems. The results have implications for the long-term green-roof performance, because wind-induced uplift or substrate displacement can alter VRA thermal behaviour; maintaining aerodynamic stability is therefore essential to sustain the intended thermal performance. The findings highlight potential failure mechanisms, particularly in unanchored lightweight VRAs, and support more resilient green-roof design and standards for industrial buildings.

大型低层工业大厅提供了广阔的屋顶区域，用于增加植被屋顶组件（VRAs），作为重建的一部分。然而，现有的结构通常需要轻量级vra来避免超载。为了评估这种轻质系统的抗风能力，在OpenFOAM中使用reynolds - average Navier-Stokes方法对低密度建筑环境中的长方体工业大厅进行了大气边界层模拟，该建筑代表了全球许多工业设施。分析了其他屋顶几何形状和相邻建筑案例，以涵盖先前研究中未解决的配置。与简单的长方体相比，长方体-斜面组合几何体的顶压明显更高。相邻建筑的存在进一步增强了角落区的吸力，将局部吸力峰值从- 608 Pa增加到- 830 Pa（37%）。对于捷克布尔诺气象站记录的43.1 m/s的极端风速，计算的压力与欧洲标准的风对结构的作用进行了比较。当风向为45°时，顶角处的吸力峰值约为- 4 kPa，约为有效面积≤1 m2的组件允许极限的两倍，这表明垂直风（0°）分析可能低估了模块化系统的风险。研究结果对绿色屋顶的长期性能有影响，因为风引起的隆起或基底位移可以改变VRA的热行为；因此，保持空气动力学稳定性对于维持预期的热性能至关重要。研究结果强调了潜在的失效机制，特别是在无锚定的轻型vra中，并支持更有弹性的绿色屋顶设计和工业建筑标准。

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引用次数: 0

Experimental and optimization study of photovoltaic panel thermal management using serrated fins and biomass-derived hybrid conductive PCM 锯齿翅片与生物质混合导电PCM光伏板热管理的实验与优化研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-20 DOI: 10.1016/j.csite.2026.107845

Xilong Bai , Junpeng Xiao , Linjun Li

This study presents a novel passive cooling system for photovoltaic (PV) panels, integrating serrated fins with shape-stabilized phase change materials (SS-PCMs) enhanced by a biomass-derived hybrid filler composed of walnut shell charcoal and graphene nanoplatelets. The hybrid filler improves thermal conductivity and prevents PCM leakage, while the serrated fins enhance heat transfer. Experiments under varying solar irradiance (300–1000 W/m²) assessed the effects of irradiance, filler weight fraction (0–10 wt%), and fin number (0–8) on PV surface temperature and electrical efficiency. Results show that the combination of fins and hybrid fillers significantly reduces PV temperature and improves heat dissipation uniformity. The optimal configuration—8 fins with 10 wt% filler—achieved a maximum temperature reduction of 24.82 °C compared to an uncooled panel, increasing electrical efficiency by 1.45% (absolute). Response Surface Methodology (RSM) revealed strong correlations between design parameters and performance, identifying solar irradiance as the most influential factor. Multi-objective optimization determined the best operating condition at 800 W/m² irradiance, yielding a PV temperature of 43.52 °C, 14.67% efficiency, and a desirability of 0.911. These findings demonstrate that combining serrated fins with biomass-enhanced SS-PCMs provides a synergistic passive cooling effect, delaying thermal saturation and improving PV system performance and durability.

该研究提出了一种新型的光伏（PV）板被动冷却系统，该系统集成了锯齿状翅片和形状稳定相变材料（SS-PCMs），该材料由核桃壳木炭和石墨烯纳米片组成的生物质衍生混合填料增强。混合填料提高了导热性，防止了PCM泄漏，而锯齿状翅片增强了传热。不同太阳辐照度（300-1000 W/m2）下的实验评估了辐照度、填料重量分数（0-10 wt%）和翅片数（0-8）对PV表面温度和电效率的影响。结果表明，翅片和混合填料的组合可以显著降低PV温度，提高散热均匀性。与未冷却的面板相比，最佳配置（8个翅片加10 wt%的填料）最大温度降低了24.82°C，电气效率提高了1.45%（绝对）。响应面法（RSM）揭示了设计参数与性能之间的强相关性，确定太阳辐照度是最重要的影响因素。多目标优化确定了800 W/m2辐照度下的最佳工作条件，得到的PV温度为43.52℃，效率为14.67%，理想度为0.911。这些研究结果表明，将锯齿翅片与生物质增强型ss- pcm相结合可以提供协同的被动冷却效果，延迟热饱和，提高光伏系统的性能和耐久性。

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引用次数: 0

A new analytical method for thermal performance prediction of multi-pass serpentine tube heat exchangers 一种新的多通道蛇形管换热器热性能预测分析方法

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-24 DOI: 10.1016/j.csite.2026.107853

Zhiwei Liu , Guoqiang Xu , Jie Wen , Bensi Dong , Laihe Zhuang

Accurate and computationally efficient prediction of thermal performance in serpentine tube heat exchangers (STHEs) is paramount for advanced aeroengine thermal management systems. Existing methods, however, often oversimplify complex flow phenomena, rendering them inadequate for identifying intricate local cross-flow interactions and their consequences, which directly impact system reliability and safety. To address this critical research gap, this paper introduces a novel analytical model for multi-pass STHEs that achieves both high accuracy and superior computational efficiency. Our model employs a unit-based approach, discretizing the STHE into repeatable single-tube row modules. By sequentially solving these modules, we achieve an accurate resolution of detailed, two-dimensional temperature distributions across the entire heat exchanger. A significant contribution of this work is the model's capability to predict and mechanistically explain the observed local inverse heat transfer phenomenon in parallel-flow configurations. This critical behavior, largely overlooked by conventional models, directly influences overall heat transfer performance. Rigorous numerical validation confirms the model's accuracy, with average deviations below 1% for the total heat transfer rate and 3.49% for the temperature distribution. Furthermore, comparative analyses reveal that our proposed analytical model significantly outperforms traditional methods in predictive accuracy. The improvement is larger than 5% when μ > 0.30 and NTU₂ > 2.83 for parallel-flow STHEs, and μ < 0.43 and NTU₂ > 0.56 counter-flow STHEs. These findings collectively demonstrate that the developed framework not only provides new physical insights into the heat transfer mechanisms governing multi-pass STHEs but also serves as an efficient computational tool for performance optimization of aerospace thermal management systems where stringent reliability constraints exist.

蛇形管换热器（STHEs）热性能的准确、高效预测对于先进的航空发动机热管理系统至关重要。然而，现有的方法往往过于简化了复杂的流动现象，使得它们不足以识别复杂的局部交叉流动相互作用及其后果，而这些相互作用直接影响系统的可靠性和安全性。为了解决这一关键的研究空白，本文介绍了一种新的多道STHEs分析模型，该模型既具有高精度又具有优越的计算效率。我们的模型采用基于单元的方法，将STHE离散成可重复的单管排模块。通过对这些模块进行顺序求解，我们可以精确地分辨出整个换热器的详细二维温度分布。这项工作的一个重要贡献是该模型能够预测和机械地解释在平行流配置中观察到的局部逆传热现象。这一关键行为在很大程度上被传统模型所忽视，直接影响整体传热性能。严格的数值验证证实了模型的准确性，总换热率的平均偏差小于1%，温度分布的平均偏差小于3.49%。此外，对比分析表明，我们提出的分析模型在预测精度上明显优于传统方法。当μ >； 0.30和NTU2 >； 2.83为平行流时，μ >； 0.43和NTU2 >； 0.56为逆流时，改善幅度大于5%。这些发现共同表明，所开发的框架不仅为控制多道STHEs的传热机制提供了新的物理见解，而且还可以作为航空航天热管理系统性能优化的有效计算工具，其中存在严格的可靠性约束。

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引用次数: 0

Thermo-mechanical behavior of clays: Divergent responses of kaolinite and montmorillonite in temperature-controlled shear tests 粘土的热力学行为：高岭石和蒙脱土在温控剪切试验中的发散响应

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-24 DOI: 10.1016/j.csite.2026.107857

Mostafa Zamanian , Meghdad Payan , Navid Afsharnia

This study examines the thermo-mechanical behavior of cohesive soils, focusing on the influence of temperature and clay mineralogy on shear strength and stiffness. Temperature-controlled direct shear tests were conducted on montmorillonite-rich bentonite and kaolinite under normal stresses of 100–300 kPa and temperatures ranging from 5 °C to 80 °C. Specimens were compacted at optimum moisture content to maximum dry density, then saturated and consolidated prior to testing. Kaolinite exhibited thermal stability, with negligible changes in strength and stiffness across the temperature range. This behavior is attributed to its low surface activity, limited interlayer water, and stable 1:1 lattice structure, which minimize thermo-hydro-mechanical interactions. Montmorillonite, in contrast, displayed a biphasic thermal response: strength and stiffness increased with temperature up to ∼60 °C, due to reduced pore water viscosity and partial dehydration enhancing interparticle bonding. Beyond this threshold, a decline in mechanical properties was observed, likely caused by the disruption of diffuse double layers and microstructural weakening. These contrasting responses underscore the critical role of mineralogy in governing soil behavior under thermal loads. The findings have direct implications for the design and safety of energy geostructures, nuclear waste containment systems, and other geotechnical applications exposed to elevated temperatures.

本研究考察黏性土的热力学行为，重点关注温度和粘土矿物对抗剪强度和刚度的影响。对富含蒙脱石的膨润土和高岭土进行了控温直剪试验，正常应力为100-300 kPa，温度范围为5℃~ 80℃。在测试前，将样品在最佳含水量下压实至最大干密度，然后饱和并固结。高岭石表现出热稳定性，在整个温度范围内强度和刚度的变化可以忽略不计。这种行为归因于其低表面活性，层间水有限，稳定的1:1晶格结构，最大限度地减少了热-水-机械相互作用。相比之下，蒙脱土表现出双相热响应：强度和刚度随着温度升高至~ 60℃而增加，这是由于孔隙水粘度降低和部分脱水增强了颗粒间的结合。超过这个阈值，观察到力学性能的下降，可能是由于弥散双层的破坏和微观结构的减弱。这些对比的响应强调了矿物学在热负荷下控制土壤行为的关键作用。这些发现对能源土工结构、核废料密封系统和其他暴露在高温下的土工应用的设计和安全具有直接意义。

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引用次数: 0

Numerical simulation of autoignition characteristics of methane/ n-dodecane dual fuel 甲烷/正十二烷双燃料自燃特性的数值模拟

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-04-01 Epub Date: 2026-02-28 DOI: 10.1016/j.csite.2026.107884

Xu Zhou, Gen Zhu, Fugang Li, Weizhi Wu, Yijun Wang, Shangming Li, Yupeng Hu

Numerical simulations were carried out to investigate the autoignition characteristics of methane/n-dodecane dual fuel under the conditions of P = 6 atm and T = 1100 K. The skeletal mechanism containing 54 species and 269 steps reaction was employed, and the performances of mechanism to cover zero-dimensional homogeneous ignition and laminar flame propagation problems in lean methane-air mixtures were demonstrated. The research results indicate that the combustion processes were divided into the inert mixing phase, the low-temperature chemical reaction phase, and the high-temperature chemical reaction phase. And there are significant competitive relationships between the two fuels during the ignition process, and the autoignition characteristics of n-dodecane in the methane/air mixture are affected by the equivalent ratio of methane. The two-stage ignition characteristics of dual fuel were discovered by direct numerical simulation. The first-stage ignitions are originated from the low-temperature chemical reaction in the richer mixtures. And the second-stage ignitions are caused by the single-stage high-temperature reaction, occurring near the equivalent mixture fraction. Increasing methane equivalent ratio will inhibit the ignition of two stages. It was determined that the elementary reaction CH₄+OH<=>CH₃+H₂O is enhanced due to the addition of methane through sensitivity analysis, resulting in increasing ignition delay times.

对甲烷/正十二烷双燃料在P = 6 atm、T = 1100 K条件下的自燃特性进行了数值模拟研究。采用包含54种物质、269步反应的骨架机制，验证了该机制在稀薄甲烷-空气混合物中零维均匀点火和层流火焰传播问题上的性能。研究结果表明，燃烧过程分为惰性混合阶段、低温化学反应阶段和高温化学反应阶段。两种燃料在点火过程中存在明显的竞争关系，甲烷/空气混合物中正十二烷的自燃特性受甲烷当量比的影响。通过直接数值模拟，发现了双燃料的二级点火特性。第一级点火是由较浓混合物中的低温化学反应引起的。二级点火是由单级高温反应引起的，发生在当量混合气分数附近。增加甲烷当量比将抑制两级的点火。通过灵敏度分析确定甲烷的加入增强了CH4+OH<；=>；CH3+H2O的初等反应，导致了点火延迟时间的增加。

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引用次数: 0