Case Studies in Thermal Engineering最新文献_第10页

Optimization of wind turbine blade airfoil considering environmental parameters uncertainty under rime conditions 时变条件下考虑环境参数不确定性的风力机叶片翼型优化

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-24 DOI: 10.1016/j.csite.2026.107739

Jingxiao Yang, Lina Hu, Yuhang Lei, Can Yang, Wei Liu

引用次数: 0

Dynamic modeling for spindle thermal error in machine tools under time-varying rotational speeds and cooling states 时变转速和冷却状态下机床主轴热误差的动态建模

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-24 DOI: 10.1016/j.csite.2026.107733

Ji Peng, Ke Yang, Zhirong Zhang, Yebing Mao, Feng Tan, Xiaobing Hu, Ming Yin, Zhoujie Zhao, Longjiang Li

引用次数: 0

Improvement solar box cooker thermal performance using metal fibers 利用金属纤维改善太阳能箱式炊具的热性能

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-24 DOI: 10.1016/j.csite.2026.107751

Osama Abd Al-Munaf Ibrahim , Saif Ali Kadhim , Ali M. Ashour , Abdallah Bouabidi , Ravishankar Sathyamurthy

This study presents an experimental investigation aimed at improving the thermal performance of a solar box cooker using metallic fibers and a booster mirror. Three identical cookers were fabricated and tested under two operating conditions: without and with a reflective mirror. Each cooker contained an equal mass of copper, aluminum, or steel fibers distributed around the cooking pot to enhance internal heat transfer. Experiments were conducted under natural solar radiation from 7:00 a.m. to 5:00 p.m., and temperatures were monitored continuously. The cooker containing copper fibers and equipped with a booster mirror achieved the best overall performance, reaching a maximum water temperature of 92.2 °C, and maintaining temperatures above 90 °C for nearly 1 h under peak solar conditions, with a second figure of merit of 0.303, a thermal efficiency of 27.34 %, and an exergy efficiency of 3.07 %. These results confirm the strong influence of copper's high thermal conductivity on energy absorption and temperature uniformity. The addition of the booster mirror increased heat gain and reduced cooking time by approximately 17 % compared with the non-reflective case. The proposed modification demonstrates that combining conductive enhancement and optical intensification can substantially improve the thermal behavior of solar box cookers, providing an effective and sustainable option for clean energy cooking applications.

本文介绍了一种利用金属纤维和助推镜改善太阳能箱式炊具热性能的实验研究。制作了三个相同的炊具，并在两种操作条件下进行了测试：没有反射镜和有反射镜。每个炊具都含有等量的铜、铝或钢纤维，分布在锅周围，以增强内部传热。实验于上午7点至下午5点在自然太阳辐射下进行，并连续监测温度。含铜纤维并配有升压镜的炊具整体性能最佳，最高水温可达92.2℃，在峰值太阳能条件下可将温度保持在90℃以上近1 h，第二优值为0.303，热效率为27.34%，火用效率为3.07%。这些结果证实了铜的高导热性对能量吸收和温度均匀性的强烈影响。与非反射的情况相比，增加助推镜增加了热量增益并减少了大约17%的烹饪时间。所提出的改进表明，结合导电增强和光增强可以大大改善太阳能箱式炊具的热性能，为清洁能源烹饪应用提供了有效和可持续的选择。

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引用次数: 0

Numerical investigation on cooperative platform smoke exhaust technology of rail-top exhaust system in subway station fires 地铁车站火灾中轨道顶排烟系统协同平台排烟技术的数值研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-24 DOI: 10.1016/j.csite.2026.107744

Wugang Huang , Xiwen Lei , Jianing Wang

Subway platform fires have the characteristics of rapid smoke spread, difficulties in smoke exhaust and in evacuating personnel. To investigate the impact of collaborative smoke exhaust design with rail-top system on the smoke exhaust performance during subway platform fires, a series of full-scale numerical simulations were conducted by taking a real subway station as an example. The variation patterns of downward velocity at stairway, as well as temperature, CO concentration and visibility at the clear height were revealed. The results indicate that the downward velocity at stairway gradually increases as the rail-top exhaust system airflow increases. The relationship between downward velocity and rail-top exhaust system velocity was proposed. When the rail-top exhaust system velocity reaches 70 m³/s, it can meet the requirement of a 1.5 m/s downward velocity at stairway. Based on the result of temperature, CO concentration, visibility indicators and the calculated smoke exhaust volume of the exhaust system according to specifications, using a rail-top fan airflow of 70 m³/s (252,000 m³/h) for collaborative smoke exhaust can meet the requirements for personnel evacuation. The results can give insights for the emergency evacuation planning, smoke control and firefighting activities in subway stations.

地铁站台火灾具有烟雾蔓延快、排烟困难、人员疏散困难等特点。为研究轨道顶系统协同排烟设计对地铁站台火灾时排烟性能的影响，以某真实地铁站为例进行了全尺寸数值模拟。揭示了楼梯向下流速的变化规律，以及清高处温度、CO浓度和能见度的变化规律。结果表明，随着轨道顶排风系统气流的增大，楼梯处的下行速度逐渐增大。提出了下向速度与轨顶排气系统速度之间的关系。当轨道顶排风系统速度达到70 m3/s时，可以满足楼梯处1.5 m/s的下行速度要求。综合温度、CO浓度、能见度等指标结果及按规范计算的排烟系统排烟量，采用70 m3/s（25.2万m3/h）的轨顶风机协同排烟，可满足人员疏散要求。研究结果可以为地铁车站的应急疏散规划、烟雾控制和消防活动提供参考。

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引用次数: 0

Molecular dynamics study on temperature-dependent interfacial thermal resistance and wettability at Ga-Diamond/Cu interfaces ga -金刚石/Cu界面热阻和润湿性的分子动力学研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-24 DOI: 10.1016/j.csite.2026.107747

Jiaqing Zhang , Abdulmajeed Mohamad , Qiuwang Wang , Wenxiao Chu

Thermal interface materials consisting of low-melting-point liquid metal indicate excellent thermal conductivity and good deformation capabilities, thereby displaying important role in thermal management applications under extreme conditions. This study introduces the molecular dynamics simulation to investigate the thermal transport and wetting behavior of Ga-Diamond and Ga-Cu solid-liquid interfaces. From 323 to 1023 K, the interfacial thermal resistance of both assemblies drops sharply as rising temperature boosts phonon coupling efficiency. Notably, analysis on the phonon participation ratio shows that Ga at the Ga-Cu interface indicates a high extended phonon share of 20 %, which is larger than that at the Ga-Diamond system (16.1 %). The interfacial phonon match illustrates dominant effect on the thermal transport difference. Moreover, the wettability analysis reveals that the contact angle θ of gallium at the two interfaces shows opposite tendency. The contact angle increases with temperature by 9.3 % on the diamond surface, whereas it reduces by 79.6 % on the Cu surface. In addition, a strong linear correlation between interfacial thermal resistance interfacial thermal resistance and cosθ is fitted, showing positive relation in the Ga-Diamond system and negative relation in the Ga-Cu system.

由低熔点液态金属组成的热界面材料具有优异的导热性和良好的变形能力，因此在极端条件下的热管理应用中发挥了重要作用。本研究采用分子动力学模拟方法研究了ga -金刚石和Ga-Cu固液界面的热传递和润湿行为。在323 ~ 1023 K范围内，随着温度的升高声子耦合效率的提高，两种组件的界面热阻急剧下降。值得注意的是，声子参与比分析表明，Ga在Ga- cu界面处的扩展声子份额高达20%，大于Ga- diamond系统的扩展声子份额（16.1%）。界面声子匹配是影响热输运差的主要因素。此外，润湿性分析表明，镓在两个界面处的接触角θ呈现相反的趋势。金刚石表面的接触角随温度升高升高了9.3%，而Cu表面的接触角随温度升高降低了79.6%。界面热阻与cost θ呈较强的线性相关关系，在ga -金刚石体系中呈正相关关系，在Ga-Cu体系中呈负相关关系。

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引用次数: 0

Cooling energy savings potential from economizer integrated with ground-coupled air duct system in Korean climate 韩国气候条件下省煤器与地面耦合风管系统的制冷节能潜力

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-24 DOI: 10.1016/j.csite.2026.107750

Minho Kim , Beungyong Park , Dongsu Kim , Sung Lok Do

This study proposes an economizer integrated with ground-coupled air duct system (EGAS) to expand the range of outdoor air (OA) conditions suitable for economizer operation and to maximize cooling energy savings under Korean climate (4A climate zone). The EGAS features an OA duct buried underground, allowing heat exchange with the relatively stable and lower-temperature soil before determining the OA intake rates of economizer. Therefore, this study aims to evaluate the cooling energy savings potential by using EGAS in the Korean climate. To achieve this, the EGAS control algorithm was developed and integrated into the Base model to conduct building energy simulations. The results showed that EGAS increased OA intake rates, extended the operating hours of economizer. Accordingly, mixed air temperatures and cooling coil loads were reduced. Specifically, the annual cumulative cooling coil loads decreased by approximately 15.9 % compared to the Basecase, HVAC energy usage was reduced by about 13 %. Additionally, the indoor dry-bulb temperature and relative humidity remained within the comfort range, indicating no degradation of thermal comfort. These findings suggest that using EGAS for OA intake is an effective strategy for cooling energy savings.

本研究提出了一种与地面耦合风管系统（EGAS）集成的省煤器，以扩大适合省煤器运行的室外空气（OA）条件的范围，并在韩国气候（4A气候带）下最大限度地节省冷却能源。EGAS采用埋于地下的OA管道，在确定省煤器OA吸收率之前，可以与相对稳定且温度较低的土壤进行热交换。因此，本研究旨在评估在韩国气候中使用EGAS的制冷节能潜力。为此，开发了EGAS控制算法，并将其集成到Base模型中进行建筑能耗模拟。结果表明，EGAS提高了OA进气率，延长了省煤器的运行时间。因此，混合空气温度和冷却盘管负荷降低。具体来说，与Basecase相比，每年累积冷却盘管负荷减少了约15.9%，暖通空调能耗减少了约13%。此外，室内干球温度和相对湿度保持在舒适范围内，表明热舒适性没有下降。这些发现表明，使用EGAS对OA的摄入是一种有效的冷却节能策略。

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引用次数: 0

Review of the state of the art in modeling and optimization of plate fin type heat exchangers 板翅式换热器的建模与优化研究进展

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-24 DOI: 10.1016/j.csite.2026.107749

Suraj Krishnamurti, James Tancabel, Vikrant Aute

Plate-fin heat exchangers (PFHX) have a very high surface area to volume ratio (>1000 m²/m³), which falls under the class of compact heat exchangers. Due to their high compactness, flexibility, and low cost, they are used in a wide variety of applications, including but not limited to the process industry, cryogenics, heating, ventilation, air-conditioning and refrigeration (HVAC&R), and aviation. This paper reviews the state of the art in the modeling and design of plate-fin heat exchangers. We first describe recent advances in performance enhancement techniques for PFHX, which are largely passive in nature, by means of novel fin structures and/or vortex generators. A systematic analysis of the physical phenomena associated with PFHXs was conducted using the Phenomenon Identification and Ranking Table (PIRT) approach, which is commonly used for modeling critical devices across a wide array of applications and can also be used to guide PFHX model development. Modeling approaches used in the literature have been summarized and categorized into 4 types: (i) Lumped, (ii) Layer stacking, (iii) Distributed and (iv) CFD. Verification, validation and uncertainty quantification of these modeling approaches are also discussed. The models available in the literature are often used to optimize PFHXs, which is a complex problem containing both continuous and discrete design variables and the existence of multiple objectives and constraints depending on the design requirements. This is an interesting area of active research, and we have reviewed the latest developments thereof. Finally, research gaps and future directions for research are discussed. We hope that this review will serve as a guide for future researchers in the modeling and optimization of PFHX.

板翅式换热器（PFHX）具有非常高的表面积体积比（>1000 m2/m3），属于紧凑型换热器的一类。由于其高紧凑性，灵活性和低成本，它们被广泛用于各种应用，包括但不限于过程工业，低温，加热，通风，空调和制冷（hvac&r）以及航空。本文综述了板翅式换热器的建模和设计的最新进展。我们首先描述了PFHX性能增强技术的最新进展，PFHX本质上主要是被动的，通过新颖的鳍结构和/或涡流发生器。使用现象识别和排位表（PIRT）方法对与PFHX相关的物理现象进行了系统分析，该方法通常用于对各种应用中的关键设备进行建模，也可用于指导PFHX模型的开发。文献中使用的建模方法被归纳为4种类型：(i)集总，（ii）层叠加，（iii）分布式和（iv） CFD。讨论了这些建模方法的验证、验证和不确定度的量化。pfhx是一个复杂的问题，包含连续和离散的设计变量，根据设计要求存在多个目标和约束。这是一个有趣的活跃研究领域，我们回顾了其最新发展。最后，对研究的空白和未来的研究方向进行了讨论。我们希望这篇综述能对今后PFHX的建模和优化研究起到一定的指导作用。

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引用次数: 0

Simulation of water-graphene oxide two-phase nanofluid flow in a porous ribbed microchannel by considering heat transfer and particle migration 考虑传热和粒子迁移的水-氧化石墨烯两相纳米流体在多孔肋状微通道中的流动模拟

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-24 DOI: 10.1016/j.csite.2026.107706

Ahmadreza Rezaei , Mohammadreza Niknejadi , Davood Toghraie , Soheil Salahshour

This study explores the effects of nanofluids, used as a dense discrete two-phase system with nanoparticle volume fractions (ϕ) ranging from 0 to 3 %, on heat transfer in a ribbed microchannel with a porous medium. Key parameters such as rib angle, Darcy number, and Reynolds number were analyzed for their effect on heat transfer and particle migration. Results indicate that increasing the Darcy number from 0 to 1.883e-4 at a 30° angle and ϕ = 3 % raised the Nusselt number from 1.8235 to 2.0376 while increasing the Reynolds number from 10 to 1000 at a 30° angle and the same ϕ raised the Nusselt number from 2.1030 to 3.7519. The maximum Nusselt number observed was 3.9047 for a microchannel with 90° ribs, Reynolds number of Re = 1000, ϕ = 3 %, and a Darcy number of 7.533e-4. Conversely, the results show that increasing the ϕ also increases fluid density and relative viscosity, leading to higher kinetic energy and maximum flow velocity in the microchannel. Finally, the results revealed that in the presence of a porous medium with a Darcy number of 1.883e-4, for micro-ribs with an angle of 90°, Re = 10, and ϕ = 1 %, the value of the friction factor increases from 0.5956 to 0.9495.

本研究探讨了纳米流体的影响，纳米流体作为密集的离散两相系统，纳米颗粒体积分数（φ）范围从0到3%，在多孔介质的肋状微通道中传热。分析了肋角、达西数、雷诺数等关键参数对传热和颗粒迁移的影响。结果表明，在30°角和φ = 3%时，当Darcy数从0增加到1.883e-4时，Nusselt数从1.8235提高到2.0376；当φ为30°角和φ相同时，当雷诺数从10增加到1000时，Nusselt数从2.1030提高到3.7519。当雷诺数Re=1000， ϕ= 3%，达西数为7.533e-4时，所观察到的最大努塞尔数为3.9047。相反，结果表明，增加ϕ也会增加流体密度和相对粘度，从而导致微通道内的动能和最大流速更高。结果表明，在达西数为1.883e-4的多孔介质存在下，对于角为90°、Re=10、ϕ=1%的微肋，摩擦因数从0.5956增加到0.9495。

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引用次数: 0

Thermal behavior of a concrete recycling unit during the transition from diesel-fired to electric hot air generator 混凝土回收装置由柴油热风发生器转换为电热风发生器时的热行为

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-23 DOI: 10.1016/j.csite.2026.107741

Nishab Ali , Osama Zaid , Abraham Teklay Gebremariam , Arun Chand , Andallib Tariq

For the advancement of sustainable and cleaner operation in concrete recycling, the Heating Air Classification System (HAS) requires replacing the existing diesel-fired burner with an electric heating technology. This study contributes to that transition by evaluating the suitability of electric hot air generators for HAS operational thermal needs. Through detailed numerical analysis, the thermal performance and flow behavior of HAS are assessed across single (Cases: A1–A4) and dual inlet (Cases: B1–B4) configurations, and for a range of hot air inlet temperatures (800–950 °C). Spatial distributions of normalized temperature, velocity, and turbulent kinetic energy (TKE) are examined on multiple planes to characterize flow behavior, heating uniformity, and mixing. The results show that an electric hot air generator can nearly match the mean bulk temperature (⟨T/T₀⟩ ≈ 0.49–0.50) achieved with diesel systems, while providing notable improvements in thermal uniformity. Among all studied scenarios, the dual inlet configuration with lower hot air injection temperature (B1) achieves the lowest standard deviation (0.080) and coefficient of variation (0.162), ensuring the most consistent heating and minimal thermal gradients. These findings highlight that an electric hot air generator can be seen as one of the promising electrification pathways for HAS, supporting enhanced energy efficiency and cleaner production in concrete recycling applications.

为促进混凝土循环再造的可持续和更清洁运作，加热空气分级系统（HAS）要求以电加热技术取代现有的柴油燃烧器。本研究通过评估电热空气发生器对HAS运行热需求的适用性，有助于实现这一转变。通过详细的数值分析，评估了HAS的热性能和流动行为，包括单（情况：A1-A4）和双入口（情况：B1-B4）配置，以及热空气入口温度范围（800-950°C）。归一化温度、速度和湍流动能（TKE）的空间分布在多个平面上进行了检查，以表征流动行为、加热均匀性和混合。结果表明，电热风发生器几乎可以匹配柴油系统实现的平均体积温度（⟨T/T0⟩≈0.49-0.50），同时提供热均匀性的显着改进。在所有研究场景中，低热空气喷射温度（B1）的双入口配置获得了最低的标准差（0.080）和变异系数（0.162），确保了最一致的加热和最小的热梯度。这些发现强调，电热风发生器可以被视为HAS的有前途的电气化途径之一，支持混凝土回收应用中提高能源效率和清洁生产。

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引用次数: 0

Thermal behavior of a buoyancy-driven oil-immersed transformer and coolant performance assessment 浮力驱动油浸式变压器的热特性及冷却剂性能评价

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-23 DOI: 10.1016/j.csite.2026.107732

Qiang Gao , Zhe Zhang , Dong Liu

The dependable operation and effective thermal management of transformers are essential to power-system stability. To tackle this, a numerical model for the buoyancy-driven oil-immersed transformer cooling system is established, focusing on the heat transfer and flow characteristics within the transformer and its influencing factors. A figure of merit (FOM) is proposed to guide the coolants' selection and development for immersion liquid cooling systems under natural convection conditions. The results show that due to the competitive interaction mechanism between local natural convection and global natural convection, the convective heat transfer capability near the left windings decreases, resulting in the left windings' temperature being significantly higher. In static mode, the oil-immersed transformer's hotspot temperature is positively correlated with the load, with a critical load of 107 %. Furthermore, the magnitude of FOM is positively correlated with the mineral insulating oil's heat dissipation performance, and its evaluation of insulating oil performance in static mode is reliable. Notably, based on the FOM's importance, the thermal properties for different mineral insulating oils are ranked as dynamic viscosity > density > thermal expansion coefficient > thermal conductivity > specific heat capacity. With the increase in temperature, only the dynamic viscosity's weight factor rises, while the other thermal properties' weight factors reduce. Moreover, compared to mineral insulating oil 2 and mineral insulating oil 3, the service life of the transformer using mineral insulating oil 1 is increased by 1.11 and 1.53 times, respectively.

变压器的可靠运行和有效的热管理对电力系统的稳定至关重要。为此，建立了浮力驱动油浸式变压器冷却系统的数值模型，重点研究了变压器内部的传热、流动特性及其影响因素。提出了一种用于指导自然对流条件下浸没式液体冷却系统冷却剂选择和研制的性能曲线。结果表明：由于局部自然对流与全局自然对流的竞争相互作用机制，左绕组附近对流换热能力降低，导致左绕组温度明显升高；在静态模式下，油浸式变压器的热点温度与负荷呈正相关，临界负荷为107%。此外，FOM的大小与矿物绝缘油的散热性能呈正相关，其在静态模式下对绝缘油性能的评价是可靠的。值得注意的是，基于FOM的重要性，不同矿物绝缘油的热性能依次为：动态粘度>；密度>；热膨胀系数>；导热系数>；比热容。随着温度的升高，只有动粘度的权重因子升高，其他热物性的权重因子降低。而且，与矿物绝缘油2和矿物绝缘油3相比，使用矿物绝缘油1的变压器的使用寿命分别提高了1.11倍和1.53倍。

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引用次数: 0