Case Studies in Thermal Engineering最新文献

英文中文

Endoreversible modeling, optimization and 3-D graphical illustration for a non-isothermal three-reservoir chemical pump based on Lewis criterion 基于Lewis准则的非等温三储层化学泵内可逆建模、优化及三维图解

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-02-01 DOI: 10.1016/j.csite.2026.107729

Lingen Chen , Shuangshuang Shi , Yanlin Ge , Huijun Feng

An endoreversible three-reservoir non-isothermal chemical-pump (NICP) cycle is modeled by equivalent combined-cycle method, taking it as combined-cycle of endoreversible two-reservoir NICP driven by endoreversible two-reservoir non-isothermal chemical-engine. Applying finite-time thermodynamics and considering heat-and-mass-transfer coupling effect following Lewis criterion, 3-D graphical illustration of NICP cycle is obtained, and expressions of rate of energy pumping (REP) and vector coefficients-of-performance (COPs) are derived. Effects of some fixed parameters on general relationship surface of REP and COPs are analyzed. At a fixed total mass-transfer coefficient, optimal distribution of mass-transfer coefficient is studied, and optimal relationship surface of three-reservoir NICP is obtained. Influence of working fluid physical properties on performance of three-reservoir NICP is analyzed and compared. 3-D graphical illustrations for three-reservoir NICP are conducive to understanding cycle processes. Results indicate that as both heat-transfer flow rate and mass-transfer flow rate increase, REP increases and vector COPs decrease. 3-D optimal relationship surface of REP and vector COPs is monotonically decreasing. Compared with three-reservoir heat-pump, REP of three-reservoir NICP increases by 114.16 %, while vector COP decreases by 4.43 %. Compared with three-reservoir isothermal-chemical-pump, REP of three-reservoir NICP increases by 896.91 %, and vector COP increases by 135.24 %. Mass-transfer process has detrimental effect on heat-transfer process. The physical properties of working fluid have no qualitative influence on performance of three-reservoir NICP, but only quantitative influence. General and optimal relationships of three-reservoir NICP include five special cases: those of two- and three-reservoir heat-pumps with Newton's heat-transfer law, those of two- and three-reservoir isothermal-chemical-pumps with diffusive mass-transfer law, and that of two-reservoir NICP following Lewis criterion. Main contributions herein are establishments of physical and mathematical models of endoreversible three-reservoir NICP and its 3-D graphical illustration, as well as REP and COP analyses and optimizations.

采用等效联合循环方法对一个内可逆三储层非等温化学泵（NICP）循环进行建模，将其视为由内可逆两储层非等温化学发动机驱动的内可逆两储层NICP的联合循环。应用有限时间热力学原理，根据Lewis准则考虑传热传质耦合效应，得到了NICP循环的三维图形表示，推导出了能量抽运率（REP）和矢量性能系数（cop）的表达式。分析了一些固定参数对REP和cop一般关系面的影响。在总传质系数一定的情况下，研究了传质系数的最优分布，得到了三库NICP的最优关系面。分析比较了工作流体物性对三层NICP性能的影响。三储层NICP的三维图解有助于理解循环过程。结果表明：随着换热流量和传质流量的增大，管道的REP增大，载体cop减小；REP与矢量cop的三维最优关系面是单调递减的。与三库热泵相比，三库NICP的REP提高了114.16%，而载体COP降低了4.43%。与三层等温化学泵相比，三层NICP的REP提高了896.91%，载体COP提高了135.24%。传质过程对传热过程有不利影响。工作流体的物理性质对三层NICP的性能没有定性影响，只有定量影响。三热源NICP的一般和最优关系包括五种特殊情况：二热源和三热源热泵符合牛顿传热定律的情况、二热源和三热源等温化学泵符合扩散传质定律的情况、二热源和三热源NICP符合刘易斯准则的情况。本文的主要贡献是建立了内可逆三储层NICP的物理和数学模型及其三维图形说明，以及REP和COP的分析和优化。

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引用次数: 0

A Hybrid-Differencing Finite Volume Method for Vortex Viscosity Controlled Thermosolutal Micropolar Nanofluid Flow in Darcy Medium with Brownian Effects 涡旋粘度控制的热溶质微极纳米流体在达西介质中布朗效应的混合差分有限体积法

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-02-01 DOI: 10.1016/j.csite.2026.107780

Kamil Abbas, Lele Yang, Ghulam Rasool, Peilin Zhu, Ming Wang

Efficient control of coupled heat and mass transfer in hybrid nanofluids is important for advanced cooling and thermal energy systems. The study numerically investigates micropolar GO–TiO2 hybrid nanofluid flow and thermo-solutal transport in an inclined lid driven cavity. The flow is assumed to be two-dimensional, laminar, and incompressible with constant thermophysical and micropolar properties along with a homogeneous Darcy porous medium under a uniform inclined magnetic field. The Hamilton–Crosser model was employed to account for the blade-shaped nanoparticles, owing to their superior thermal conductivity. Micropolar fluid theory was implemented to observe vortex viscosity and microrotation effects. The effects of thermophoresis, Brownian motion, thermal radiation, and magnetic field inclination, were analyzed through self-developed MATLAB code to implement Finite Volume Method (FVM). The parametric sweep revealed that reduction in Darcy number from 10-1 to 10-3 resulted in elevated flow resistance which led to lowering of heat transfer by about 5% and concentration buildup by 8%. Increasing the Hartmann number from 20 to 80 enhances the heat transfer rate by about 6%. The micropolar parameter elevation from 1 to 7 further suppressed the heat transfer rate by roughly 12%. Overall, the results suggests that combined influence of micropolarity, magnetic fields, porous resistance, and radiative effects offer valuable insights into transport enhancement in hybrid nanofluids, which is relevant for the design of compact cooling devices and thermal energy conversion components.

高效控制混合纳米流体中的传热传质耦合对于先进的冷却和热能系统具有重要意义。本文通过数值模拟研究了微极性GO-TiO2杂化纳米流体在斜盖驱动腔中的流动和热溶质输运。假定流体为二维、层流、不可压缩，具有恒定的热物理和微极性性质，在均匀倾斜磁场下沿均匀达西多孔介质流动。由于叶片状纳米颗粒具有优异的导热性，因此采用Hamilton-Crosser模型来解释叶片状纳米颗粒。应用微极流体理论观察了涡旋粘度和微旋转效应。通过自主开发的MATLAB代码实现有限体积法（FVM），分析了热泳、布朗运动、热辐射和磁场倾角的影响。参数扫描显示，达西数从10-1减少到10-3，导致流动阻力增加，传热降低约5%，浓度累积降低8%。将哈特曼数从20增加到80，传热率提高约6%。微极参数从1提高到7进一步抑制了约12%的换热速率。总体而言，研究结果表明，微极性、磁场、多孔电阻和辐射效应的综合影响为混合纳米流体中的输运增强提供了有价值的见解，这与紧凑冷却装置和热能转换组件的设计有关。

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引用次数: 0

Experimental analysis of an R134a refrigeration system using POE/CuO nanolubricant POE/CuO纳米润滑剂R134a制冷系统的实验分析

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-02-01 DOI: 10.1016/j.csite.2026.107734

Asasei Unarine Casey Ndanduleni, Teboho Ramathe, Zhongjie Huan

Recent research in nanofluid application in refrigeration systems emphasise heat transfer enhancement and energy consumption reduction. There are limited experimental studies on how nanoparticles influence compressor operating pressures and discharge temperatures. This research addresses this gap by experimentally investigating the impact of 10 nm CuO nanoparticles on the performance of an R134a vapour compression refrigeration system. Nanoparticles were dispersed in Polyolester (POE) oil at mass concentrations of 0.025 %–0.30 %. Effects of nanoparticles on compressor suction and discharge pressures, pressure ratio, discharge temperature, refrigerating effect, compressor work, and coefficient of performance (COP) were studied. The results signified that CuO has minimal effect on compressor suction pressure while the discharge pressure decreased by up to 16.29 %, indicating reduced friction at the piston-cylinder interface. Compressor's discharge temperature was lowered by up to 16.54 %, which potentially reduces oil breakdown. Refrigerating effect improved by up to 8.58 % due to enhanced evaporator heat transfer and nucleation site formation. Compressor work reduced by up to 20.33 %, which is attributed to improved lubrication and reduced frictional losses. System COP reached an improvement of 35.89 % at 0.25 % mass concentration, demonstrating a substantial increase in energy performance. These experimental findings demonstrate the potential of CuO nanolubricant as an energy efficiency solution in refrigeration systems.

近年来纳米流体在制冷系统中的应用研究强调强化传热和降低能耗。关于纳米颗粒如何影响压缩机工作压力和排气温度的实验研究有限。本研究通过实验研究10纳米CuO纳米颗粒对R134a蒸汽压缩制冷系统性能的影响，解决了这一空白。纳米粒子以0.025% - 0.30%的质量浓度分散在聚脂油中。研究了纳米颗粒对压缩机吸排气压力、压力比、排气温度、制冷效果、压缩机工作效率和性能系数（COP）的影响。结果表明，CuO对压缩机吸入压力的影响最小，而排气压力降低了16.29%，表明活塞-气缸界面摩擦减小。压缩机的排气温度降低了16.54%，有可能减少油的分解。由于蒸发器的传热和成核部位的形成，制冷效果提高了8.58%。压缩机的工作减少了20.33%，这归功于润滑的改善和摩擦损失的减少。在0.25%的质量浓度下，系统COP提高了35.89%，能源性能大幅提高。这些实验结果证明了氧化铜纳米润滑剂作为制冷系统节能解决方案的潜力。

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引用次数: 0

Thermal Regulation and Frost Control of Subgrade by a Ground Source Heat Pump System 基于地源热泵系统的路基热调节与结霜控制

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-02-01 DOI: 10.1016/j.csite.2026.107790

Tianfei Hu, Rui Yang, Zuren Yue, Song Zhang, Yanqiu Shi, Taofan He, Zhifeng Ren

In response to subgrade frost heave damage in cold regions, an active heating method that utilizes geothermal energy is proposed. By using ground source heat pump technology, a dedicated heat regulation system and a distributed heating scheme are designed for the subgrade. A full-scale subgrade test platform is built to test the heating performance and subgrade thermal regulatory mechanisms of this system in winter. The test results show that in the operation mode with a start: stop ratio of 2 h:1 h, the heat regulation system can reach heat supply temperatures of 17∼33 °C. Moreover, the operating performance under cold winter conditions is stable. The coefficient of performance of the thermal regulation system can exceed 5.8, but it decreases with increasing time. The heat diffusion process from the heat supply pipe to the subgrade exhibits spatial hysteresis. Within 4 d, heat can diffuse in the vertical direction throughout surface layer of the subgrade. Furthermore, the magnitude of the increase in temperature gradually decreases with increasing distance from the heat supply pipe or with increasing time. After 4 d of heating, heat diffuses in the longitudinal direction at a distance of 125 cm in the subgrade. The variation in the freezing depth of the subgrade is controlled by both the atmospheric environment and the thermal regulation system. After 16 d of heating, the freezing depth decreases from 74 cm to less than 17 cm.

针对寒冷地区路基冻胀破坏，提出了一种利用地热能进行主动加热的方法。采用地源热泵技术，设计了路基专用热调节系统和分布式采暖方案。搭建了全尺寸路基试验平台，对该系统冬季采暖性能和路基热调节机制进行了测试。试验结果表明，在启动：停止比为2 h:1 h的运行模式下，热调节系统可以达到17 ~ 33℃的供热温度。此外，在寒冷的冬季条件下运行性能稳定。热调节系统的性能系数可超过5.8，但随时间的增加而减小。从供热管道到路基的热扩散过程表现出空间滞后性。在4 d内，热量可以沿垂直方向扩散到整个路基表层。此外，温度升高幅度随距离供热管道的增加或时间的增加而逐渐减小。加热4 d后，热量在路基内沿纵向125cm方向扩散。路基冻结深度的变化受大气环境和热调节系统的共同控制。加热16 d后，冻结深度由74 cm减小到17 cm以下。

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引用次数: 0

Study on refrigeration regulation and control optimization for multi-system integrated vehicle thermal management system 多系统集成车辆热管理系统制冷调控优化研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-02-01 DOI: 10.1016/j.csite.2026.107728

Yuan Gao , Qing Gao , Jianwei Lv

With the diversification and complexity of vehicle thermal management requirements, the integration and control of different subsystems for specific utilizations require effective architectures and methods. This paper proposes a hierarchical control architecture that defines the control logic for multi-system through framework design. Based on this, the study focuses on a multi-system integrated vehicle thermal management system including battery, air conditioner and vehicle refrigerator characterized by low refrigeration temperature and high integration complexity. Through the refrigeration regulation method based on the Variable Openings Valve (VOV) and proposed Compressor-Valve Synergistic Enhancement (CVSE) method, cooling assurance for multi-system is achieved while ensuring the thermal safety of the battery and the comfort of the cabin. Subsequently, by analyzing the operational mode and operational process, the study explored their impact on the temperature system control performance and energy efficiency, thus optimizing the operation of the CVSE method. Furthermore, implement the operation optimization, a multi-criteria fusion control strategy is designed for complex actual loaded operating condition, introducing vehicle speed, ambient conditions, and subsystems temperature as input parameters. The results indicated that compared to conventional strategy that does not utilize operation optimization, the proposed strategy achieved approximately 10.8 % improvement in COP while maintaining effective temperature control under harsh operating conditions, achieving a balance between temperature control effectiveness and energy economy.

随着汽车热管理需求的多样化和复杂性，针对特定用途对不同子系统的集成和控制需要有效的体系结构和方法。本文提出了一种分层控制体系结构，通过框架设计来定义多系统的控制逻辑。在此基础上，研究了包含电池、空调和车载冰箱在内的低制冷温度、高集成复杂度的多系统集成车载热管理系统。通过基于可变开度阀（VOV）的制冷调节方法和提出的压阀协同增强（CVSE）方法，在保证电池热安全性和客舱舒适性的同时，实现了多系统的制冷保障。随后，通过分析运行模式和运行流程，探讨其对温度系统控制性能和能效的影响，从而优化CVSE方法的运行。在此基础上，针对复杂的实际负载工况，引入车速、环境条件和子系统温度作为输入参数，设计了多准则融合控制策略，实现了运行优化。结果表明，与不利用运行优化的常规策略相比，该策略在恶劣工况下保持有效温度控制的同时，COP提高了约10.8%，实现了温度控制效果和能源经济性的平衡。

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引用次数: 0

Fuel Mixing and thermal Enhancement Behind an Inclined Strut in a Supersonic Combustor via single Annular with Air-Assisted Injector 超音速燃烧室斜支板后单环空气辅助喷油器的燃料混合与热增强

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-02-01 DOI: 10.1016/j.csite.2026.107786

Yassine Bouazzi, Zakarya Ahmed, Ali Basem, As'ad Alizadeh, Mohamed Shaban, Abdellatif M. Sadeq, Walid Aich, Borhen Louhichi

In the present investigation, thermal and mixing efficiencies of the fuel jet behind the strut within combustor of scramjet engine have been extensively investigated. Combination of annular with/without internal air flow in two strut angles of 15° and 7.5 are analyzed via three-dimensional modelling of fuel jet released from single injector. Important flow features and vortex structure are evaluated to reveal the mixing nature of the proposed system. Computational fluid dynamic is used for the modelling of flow in combustor via solving RANS equations with SST turbulence model. The results reveal that the combination of a 7.5° strut angle with an internal air jet results in a 31% improvement over the baseline annular-only case at the same angle, achieving the highest mean mixing index of 0.495. Although the 15° strut with internal air jet produces the highest initial circulation strength (∼0.85), its mixing effect diminishes more rapidly downstream due to strong localized flow separation. In contrast, the 7.5° case with air assist maintains strong and consistent circulation (∼0.60 to 0.30) over a longer distance, leading to superior mixing uniformity. The internal air jet significantly enhances the breakup of the annular jet, introduces central vortices, and increases fuel-air interface area in all cases. These findings demonstrate that an inclined strut with integrated air-assisted annular injection, particularly at moderate angles, offers energy-efficient solution for improving fuel-air mixing in high-speed combustion applications.

在本研究中，对超燃冲压发动机燃烧室支杆后燃油射流的热效率和混合效率进行了广泛的研究。通过对单喷油器释放燃油射流的三维建模，分析了15°和7.5°两支杆角下环空有/无内气流组合情况。对重要的流动特征和涡结构进行了评估，以揭示所提出系统的混合性质。采用计算流体力学方法，利用SST湍流模型求解RANS方程，对燃烧室内部流动进行了模拟。结果表明，在相同角度下，7.5°支杆角与内部空气射流的组合比基线环空情况提高了31%，实现了最高的平均混合指数0.495。虽然带有内部空气射流的15°支板产生最高的初始循环强度（~ 0.85），但由于强烈的局部流动分离，其混合效果在下游更快地减弱。相比之下，7.5°的情况下，空气辅助保持强大和一致的循环（~ 0.60至0.30）在较长的距离，导致优越的混合均匀性。在所有情况下，内部空气射流都显著增强了环形射流的破裂，引入了中心涡，并增加了燃料-空气界面面积。这些研究结果表明，在高速燃烧应用中，集成空气辅助环形喷射的倾斜支撑，特别是在中等角度下，为改善燃料-空气混合提供了节能解决方案。

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引用次数: 0

Performance analysis and optimization of two-stage desiccant wheel cooling systems in low-latitude island with hot and humid climate 低纬度湿热海岛两级干燥剂轮冷却系统性能分析与优化

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-02-01 DOI: 10.1016/j.csite.2026.107714

Yingya Chen , Zelin Chen , Yongxiang Liang , Lei Li , Zhiwei Wang

In low-latitude islands characterized by extreme humidity and heat, effective dehumidification and cooling are essential for indoor environmental comfort. However, energy supply challenges persist due to geographical isolation, necessitating energy-efficient systems with stable operation. This study proposes three dehumidification/cooling systems tailored to such climates, utilizing dual solid desiccant wheels. Comparative analysis revealed the solar-powered two-stage desiccant wheel coupled with mechanical refrigeration (SDW-VCR) system as optimal. After optimization, peak thermodynamic performance (COP_th = 1.32) was achieved at a 30 % return air ratio and 85 °C regeneration temperature. The system delivers 57.2 kW total cooling capacity, with the refrigeration unit handling 11.6 kW (20.3 %) of sensible heat. Notably, the condenser inlet air temperature approximates ambient conditions due to high evaporation temperatures, yielding a refrigeration COP of 4.85. Regeneration heating demand was reduced by preheating air through condensation heat recovery. These findings establish a reference framework for sustainable thermal environment management in high-humidity tropical islands.

在低纬度的岛屿，极端潮湿和炎热的特点，有效的除湿和冷却是必不可少的室内环境舒适。然而，由于地理隔离，能源供应挑战仍然存在，需要稳定运行的节能系统。本研究提出了三种适合此类气候的除湿/冷却系统，利用双固体干燥剂轮。对比分析表明，太阳能两级干燥剂轮与机械制冷（SDW-VCR）系统是最优方案。优化后，在回风比为30%，再生温度为85℃时，达到了最大的热力学性能（COPth = 1.32）。该系统提供57.2 kW的总制冷量，制冷机组处理11.6 kW（20.3%）的显热。值得注意的是，由于高蒸发温度，冷凝器入口空气温度近似于环境条件，制冷COP为4.85。通过冷凝热回收对空气进行预热，降低了回热需求。这些发现为高湿热带岛屿可持续热环境管理提供了参考框架。

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引用次数: 0

Analysis of cooling system topology of dual stack proton exchange membrane fuel cell system for heavy-duty truck 重型载重汽车双堆质子交换膜燃料电池冷却系统拓扑结构分析

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-31 DOI: 10.1016/j.csite.2026.107781

Huu Linh Nguyen, Dongkeun Song, Sy Vong Le, Yoora Choi, Sangseok Yu

引用次数: 0

Thermal Management of Rocket Nozzles Using MHD Copper-Ionic Liquid Nanofluid in Jeffery-Hamel Flow 基于MHD铜离子液体纳米流体的火箭喷嘴杰弗瑞-哈默尔流热管理

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-31 DOI: 10.1016/j.csite.2026.107752

Umar Farooq, Yaqiao Han, Tao Liu, Hinza Sultan, Ali Alshamrani

引用次数: 0

Experimental investigation on heat transfer of subcritical diesel in horizontal tubes: carbon deposition behavior and inhibition effect 亚临界柴油水平管内换热实验研究：积碳行为及抑制效果

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-31 DOI: 10.1016/j.csite.2026.107767

Liyao Pang, Ningbo Zhao, Zixuan Feng, Zongfu Li, Honghao Xu, Xiaotao Yang

引用次数: 0

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