Applied Thermal Engineering最新文献_第4页

Fire risk assessment of lithium-ion power banks: An integrated experimental and analytical study 锂离子电池火灾风险评估：综合实验与分析研究

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-28 DOI: 10.1016/j.applthermaleng.2026.130039

Fuqiang Yang , Menghui Zhang , Kuijie Li , Qingsong Wang , Zonghou Huang

The proliferation of lithium-ion power banks poses significant fire hazards, yet research on their fire risks remains scarce. Therefore, this pioneering study systematically investigates the combustion behavior of power banks and their components under different states of charge (SOC) through cone calorimeter tests and localized overheating experiments. A comprehensive risk assessment framework is established based on fire characteristic parameters, principal component analysis (PCA), and risk matrices. Results illustrate that both power bank units (PBUs) and cells (PBCs) undergo four combustion stages: localized ignition, full ignition, thermal runaway (TR) and extinction. And the heat release rate (HRR) curves exhibit a bimodal characteristic. Key combustion parameters, including the peak value of heat release rate (HRR_peak) and total heat release (THR), are positively correlated with SOC. Furthermore, PBUs exhibit lower HRR_peak and combustion intensity than PBCs at identical SOC levels. Component contribution analysis indicates a nonlinear coupling effect where the whole is not equal to the sum of its parts for THR parameters. The power bank enclosure serves as the primary source of heat and smoke (contributing over 55%), while PBC contributes secondarily (ranging from 4% to 39%). Localized overheating experiments further confirm that the severity of TR in PBUs positively correlates with SOC. PCA extracts two primary dimensions representing “total yield” and “maximum combustion intensity”. Combined with the risk matrix, these confirm that PBUs exhibit highest fire hazard level across four SOC conditions. This study provides experimental evidence and theoretical support for fire risk prevention and safety design in power banks.

锂离子电池的普及带来了巨大的火灾隐患，但对其火灾风险的研究仍然很少。因此，本开创性研究通过锥形量热仪测试和局部过热实验，系统地研究了充电宝及其组件在不同充电状态下的燃烧行为。建立了基于火灾特征参数、主成分分析（PCA）和风险矩阵的综合风险评估框架。结果表明，充电宝单元（PBUs）和电池（PBCs）的燃烧均经历了四个阶段：局部点火、完全点火、热失控（TR）和熄灭。热释放率（HRR）曲线呈现双峰特征。热释放率峰值（HRRpeak）和总放热量（THR）等关键燃烧参数与荷电状态呈正相关。此外，在相同SOC水平下，PBUs的HRRpeak和燃烧强度均低于PBUs。分量贡献分析表明，THR参数存在整体不等于各部分之和的非线性耦合效应。移动电源外壳是热量和烟雾的主要来源（贡献超过55%），而PBC的贡献次要（从4%到39%不等）。局部过热实验进一步证实了PBUs中TR的严重程度与SOC呈正相关。主成分分析提取两个主要维度表示“总产量”和“最大燃烧强度”。结合风险矩阵，这些结果证实了PBUs在四种SOC条件下表现出最高的火灾危险等级。本研究为移动电源的火灾风险防范和安全设计提供了实验依据和理论支持。

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引用次数: 0

Leveraging thermal-fluid-solid coupling to unlock higher system performance in linear range extender 利用热流固耦合，解锁更高的系统性能，在线性增程器

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-28 DOI: 10.1016/j.applthermaleng.2026.129985

Shuo Qin, Lei Xu, Weishuo Gao, Chang Liu, Boru Jia, Peirong Ren, Yidi Wei

Free-piston engine generators (FPEG) are promising linear range extenders for hybrid powertrains, boasting potential gains in energy conversion over conventional crankshaft engines (CSE). However, prevailing thermal analyses rely on a uniform wall temperature assumption, failing to capture critical thermal-fluid-solid interactions under nonlinear piston dynamics and hindering cooling strategy development. This study bridges this gap with a novel explicit coupled method featuring dual-loop iteration, which for the first time resolves the spatiotemporal evolution of chamber thermal status via bidirectional combustion-conjugate heat transfer coupling. The effects of key cooling system parameters, including inlet condition, topology, and configuration, on energy conversion are subsequently evaluated. Our results demonstrate that the thermal-fluid-solid coupling effect undercuts the previous gains in heat loss and indicated thermal efficiency (ITE) for FPEG over CSE as obtained under the uniform-temperature assumption. The complex interplay between non-uniform cooling and nonlinear trajectory constrains the effective ranges of cooling solutions for simultaneous above gains, often degrading combustion quality. In response, we introduce a partitioned-optimization cooling scheme with the thermal consideration in practical cooling capacity and specific motion patterns, yielding ITE gains of 0.59% (Ω = 0.5) and 0.65% (Ω = 0.8) in two asymmetric trajectories. Furthermore, a general cooling design principle is also established to guide the thermal management across diverse conditions. Overall, this work provides a novel and generalized thermal analysis framework for multi-physics interactions, equipping practitioners with critical strategies for cooling design in linear range extenders with complex nonlinear dynamics.

自由活塞发动机发电机（FPEG）是混合动力系统的线性增程器，与传统曲轴发动机（CSE）相比，在能量转换方面具有潜在的优势。然而，主流的热分析依赖于均匀壁面温度假设，无法捕捉非线性活塞动力学下的临界热-流-固相互作用，阻碍了冷却策略的发展。本研究采用一种新颖的双环迭代显式耦合方法弥补了这一空白，该方法首次通过双向燃烧-共轭传热耦合解决了燃烧室热状态的时空演变。随后评估了关键冷却系统参数（包括进口条件、拓扑结构和配置）对能量转换的影响。我们的研究结果表明，热-流-固耦合效应削弱了之前的热损失收益，并表明在均匀温度假设下，FPEG的热效率（ITE）高于CSE。非均匀冷却和非线性轨迹之间的复杂相互作用限制了同时获得上述增益的冷却解决方案的有效范围，通常会降低燃烧质量。作为回应，我们引入了一种分区优化冷却方案，考虑了实际冷却能力和特定运动模式的热因素，在两个非对称轨迹中获得0.59% （Ω = 0.5）和0.65% （Ω = 0.8）的ITE增益。此外，还建立了通用的冷却设计原则，以指导不同条件下的热管理。总的来说，这项工作为多物理场相互作用提供了一个新的和广义的热分析框架，为具有复杂非线性动力学的线性范围扩展器的冷却设计提供了关键策略。

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引用次数: 0

Performance Analysis and Optimization of a Dual-Layer Microchannel Heat Sink Enhanced by Impinging Jets and Fin-Induced Disturbance 冲击射流和翅片扰动增强双层微通道散热器的性能分析与优化

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-28 DOI: 10.1016/j.applthermaleng.2026.129988

Wei Sun , Jingzhe Xie , Hui Guo , Chongchong Li , Wenzhi Nan , Yanping Wang , Han Shen , Xiaobo Ge

The continuous improvement of microelectronic device performance is increasingly constrained by rapidly rising heat flux densities, making efficient thermal management a major challenge. The authors discussed a novel dual-layer microchannel heat sink with central impinging jets and diamond-shaped fins to enhance heat transfer performance. All possible configurations involving two representative flow schemes were numerically investigated. Samples were manufactured using SLM technology. The designed and implemented experiment agree well with the numerical simulation. The results indicate the flow configuration combining both lateral and jet inlets provide superior global temperature uniformity with lower energy consumption. The fins arranged at the fluid intersection region generate strong flow disturbances, which further promote heat transfer. At an inlet velocity of

0.6 m / s

, the working condition IJFMHS-B demonstrated the best overall performance, which includes fins, and the coolant is injected simultaneously at the side and top inlets. Compared with the baseline design, the average substrate temperature decreased by

5.1 K

, the temperature difference was reduced by

11.7 K

, and the pressure drop decreased by 26.3%. The overall performance evaluated using the PEC factor of IJFMHS-B exhibited an enhancement of up to 34.9%. Moreover, the effect of jet flow ratio was explored. Considering the heat dissipation, power consumption, and temperature uniformity, the optimal range was identified between 45% and 50%. Finally, a Latin hypercube sampling (LHS) strategy was employed to construct precise surrogate models of the objective functions, and the main fin dimensions were optimized using the NSGA-II algorithm. The predicted optimal solutions showed an error of less than 3% under the assigned weighting conditions.

微电子器件性能的持续改进越来越受到热通量密度快速上升的限制，使有效的热管理成为一项重大挑战。本文讨论了一种新型的双层微通道中央冲击射流和菱形翅片散热器，以提高传热性能。对涉及两种代表性流动方案的所有可能构型进行了数值研究。样品采用SLM技术制造。设计和实现的实验结果与数值模拟结果吻合较好。结果表明，侧向和射流相结合的流动结构具有较好的整体温度均匀性和较低的能耗。布置在流体交汇区域的翅片会产生强烈的流动扰动，进一步促进换热。在进口速度为0.6m/s时，工况IJFMHS-B表现出最佳的综合性能，包括翅片，冷却剂在侧面和顶部进口同时注入。与基线设计相比，衬底平均温度降低5.1K，温差减小11.7K，压降减小26.3%。使用IJFMHS-B的PEC因子评价的整体性能提高了34.9%。此外，还探讨了射流比的影响。考虑到散热、功耗和温度均匀性，最佳范围为45% ~ 50%。最后，采用拉丁超立方体采样（LHS）策略构建目标函数的精确代理模型，并采用NSGA-II算法对主鳍尺寸进行优化。在给定的加权条件下，预测的最优解误差小于3%。

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引用次数: 0

Effects of injection strategies on the performance of reactivity-controlled compression ignition ammonia-diesel dual-fuel engine 喷射策略对反应控制压燃氨柴油双燃料发动机性能的影响

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-28 DOI: 10.1016/j.applthermaleng.2026.129902

Xianghe Chu , Junjie Liu , Peng Zou , Zezhou Guo , Xiongbo Duan

Against the backdrop of energy conservation and emission reduction, ammonia has emerged as a highly promising alternative fuel for internal combustion engines (ICEs) due to cost advantages and maturity of its storage and transportation infrastructure. However, it is difficult for ammonia to be large-scale applied in the ICEs due to its difficulty in ignition and slow laminar flame speed. One effective approach to address these issues is to blend ammonia with high active fuels, which not only ensures performance but improves emission characteristics. Nevertheless, the operating conditions for ammonia-diesel dual-fuel (ADDF) engines are difficult to expand widely and maintain high combustion efficiency. To tackle these challenges, this paper comprehensively studies the injection strategies to improve the performance of ADDF engine under the speed of 1500 rpm by adjusting the start of injection (SOI) and introducing pilot injection. The results indicate that advancing SOI significantly improves combustion process and outputted work, however, excessive advance will deteriorate the engine performance. When the SOI is set to 25 °CA before the top dead center, the ADDF engine achieves a maximum indicated mean effective pressure (IMEP) of 0.787 MPa and a maximum indicated thermal efficiency (ITE) of 44.24%. Meanwhile, the lowest CO emission of 0.37 g/kWh and the lowest unburned ammonia emission of 8163 ppm are also obtained under this condition. In addition, ADDF engine generally exhibits favorable performance in the presence of pilot injection. This is specifically reflected in the fact that the IMEP is generally greater than 0.7 MPa and the ITE is generally greater than 40%. When the pilot injection ratio (PIR) is 60%, the engine achieves a maximum IMEP of 0.74 MPa and a peak ITE of 41.6%.

在节能减排的大背景下，氨因其成本优势和成熟的储运基础设施而成为极具前景的内燃机替代燃料。然而，由于氨的点火困难和层流火焰速度慢，使其难以在内燃机中大规模应用。解决这些问题的一个有效方法是将氨与高活性燃料混合，这不仅保证了性能，而且改善了排放特性。然而，氨柴油双燃料（ADDF）发动机的运行条件难以广泛扩展并保持较高的燃烧效率。为了应对这些挑战，本文综合研究了在1500 rpm转速下，通过调整喷射启动（SOI）和引入先导喷射来提高ADDF发动机性能的喷射策略。结果表明，调高SOI可显著改善燃烧过程和输出功，但调高过高会导致发动机性能下降。当SOI设置为上止点前25°CA时，ADDF发动机的最大指示平均有效压力（IMEP）为0.787 MPa，最大指示热效率（ITE）为44.24%。同时，在此条件下，CO排放量最低为0.37 g/kWh，未燃烧氨排放量最低为8163 ppm。此外，ADDF发动机在先导喷射的情况下通常表现出良好的性能。具体表现在IMEP一般大于0.7 MPa， ITE一般大于40%。当先导喷射比（PIR）为60%时，发动机最大IMEP为0.74 MPa，峰值ITE为41.6%。

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引用次数: 0

Comparative assessment and feasibility for GSHP-based shallow geothermal energy application in Chengdu, China 成都地源热泵浅层地热能应用可行性对比评价

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-28 DOI: 10.1016/j.applthermaleng.2026.130031

Xin Xu , Jiaxin Zheng , Licheng Sun , Xiting Long , Tianyi Gao , Cunbao Li , Biao Li , Jun Wang , Zhengyu Mo , Min Du , Yongkang Luo , Huajie Zhong , Heping Xie

This study evaluates the performance of ground-source heat pumps (GSHPs) in utilizing shallow geothermal energy (SGE) in Chengdu, China, based on operational and measured data from field projects. The analysis focuses on the technical feasibility, economic viability, and environmental benefits of GSHP systems for heating and cooling. It reveals significant potential for GSHP adoption in Chengdu, despite limited current implementation, with only 47 GSHP projects (covering 3

\times 1 0^{6} m^{2}

) installed by 2021. The average heat exchange rates for borehole in Chengdu is evaluated at 51.0 W/m (winter) and 59.2 W/m (summer) based on measured data, suggesting excellent shallow geothermal resource potential. Land use analysis demonstrates that 6% of available area (1.13

\times 1 0^{6} m^{2}

) is required for borehole installation to serve 2

\times 1 0^{6} m^{2}

of new buildings. Economic analysis indicates strong feasibility, with levelized energy costs ranging from 52.99 to 80.71 CNY/GJ, a 14-year payback period, and an internal rate of return of 9.91% over a 30-year lifespan. Environmental assessment shows substantial benefits, with potential CO

_{2}

emission reductions reaching 878,117 tons for a 20

\times 1 0^{6} m^{2}

implementation area. The study demonstrates GSHP technology as an effective, eco-friendly, and sustainable solution to address Chengdu’s heating and cooling needs, offering significant economic and environmental advantages despite the region’s abundant hydropower resources.

本研究基于现场项目的运行和测量数据，评估了中国成都地源热泵（GSHPs）在利用浅层地热能（SGE）方面的性能。分析的重点是技术可行性，经济可行性和地源热泵系统的采暖和制冷环境效益。尽管目前实施有限，但它显示了成都采用地源热泵的巨大潜力，到2021年仅安装了47个地源热泵项目（覆盖3×106m2）。根据实测数据，成都地区钻孔平均热交换率分别为冬季51.0 W/m和夏季59.2 W/m，具有良好的浅层地热资源潜力。土地利用分析表明，需要6%的可用面积（1.13×106m2）用于钻孔安装，以服务2×106m2的新建筑。经济分析表明具有较强的可行性，平准化能源成本为52.99 - 80.71元/吉焦，投资回收期为14年，30年使用寿命的内部收益率为9.91%。环境评估显示了巨大的效益，在20×106m2执行区域可能减少的二氧化碳排放量达到878117吨。该研究表明，地源热泵技术是一种有效、环保和可持续的解决方案，可以满足成都的供暖和制冷需求，尽管该地区拥有丰富的水电资源，但仍具有显著的经济和环境优势。

{"title":"Comparative assessment and feasibility for GSHP-based shallow geothermal energy application in Chengdu, China","authors":"Xin Xu , Jiaxin Zheng , Licheng Sun , Xiting Long , Tianyi Gao , Cunbao Li , Biao Li , Jun Wang , Zhengyu Mo , Min Du , Yongkang Luo , Huajie Zhong , Heping Xie","doi":"10.1016/j.applthermaleng.2026.130031","DOIUrl":"10.1016/j.applthermaleng.2026.130031","url":null,"abstract":"<div><div>This study evaluates the performance of ground-source heat pumps (GSHPs) in utilizing shallow geothermal energy (SGE) in Chengdu, China, based on operational and measured data from field projects. The analysis focuses on the technical feasibility, economic viability, and environmental benefits of GSHP systems for heating and cooling. It reveals significant potential for GSHP adoption in Chengdu, despite limited current implementation, with only 47 GSHP projects (covering 3<span><math><mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>6</mn></mrow></msup><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span>) installed by 2021. The average heat exchange rates for borehole in Chengdu is evaluated at 51.0 W/m (winter) and 59.2 W/m (summer) based on measured data, suggesting excellent shallow geothermal resource potential. Land use analysis demonstrates that 6% of available area (1.13<span><math><mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>6</mn></mrow></msup><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span>) is required for borehole installation to serve 2<span><math><mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>6</mn></mrow></msup><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span> of new buildings. Economic analysis indicates strong feasibility, with levelized energy costs ranging from 52.99 to 80.71 CNY/GJ, a 14-year payback period, and an internal rate of return of 9.91% over a 30-year lifespan. Environmental assessment shows substantial benefits, with potential CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> emission reductions reaching 878,117 tons for a 20<span><math><mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>6</mn></mrow></msup><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span> implementation area. The study demonstrates GSHP technology as an effective, eco-friendly, and sustainable solution to address Chengdu’s heating and cooling needs, offering significant economic and environmental advantages despite the region’s abundant hydropower resources.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"289 ","pages":"Article 130031"},"PeriodicalIF":6.9,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Thermal and ventilation performance of the innovative asymmetrical flexible wall greenhouse for annual usage 每年使用的创新的不对称柔性墙温室的热和通风性能

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-28 DOI: 10.1016/j.applthermaleng.2026.129969

Hongyu Sun , Zihao Qi , Qian Zhang , Zongmei Xu , Wei Zheng , Min Wei , Guiyuan Liu , Shaojie Wang

This paper propose a novel asymmetric flexible wall greenhouses (AFWG), which has high land utilization and annual use advantages. In this paper, a multi-field coupling model of AFWG in winter and summer was established using the in-situ test method and computational fluid dynamics. The thermal and ventilation performance of the AFWG was verified; the influence of shallow soil on temperature fluctuation and heat exchange was revealed, and the shallow soil was the main heat storage area. During both day and night, the effective heat storage depth and effective heat release depth of the soil are approximately 30 cm and 25 cm respectively, and the daily effective heat conversion rate of the soil calculation was 48.1%. The influence of crop height and ventilation opening degree on the ventilation & cooling performance of the greenhouse was clarified. The ventilation efficiency gradually increased when the north wall vent opening was increased from 0.6 m to 1.8 m, the ventilation efficiency in the crop area increased from 1.40 to 2.09 with crop height was 0.5 m, and the ventilation efficiency in the crop area increased from 3.10 to 5.06 with crop height was 1.2 m. This paper provided a case and basis for annual usage of the AFWG.

本文提出了一种具有高土地利用率和年利用优势的新型非对称柔性墙体温室。本文采用现场试验方法和计算流体力学方法，建立了冬季和夏季AFWG的多场耦合模型。验证了AFWG的散热和通风性能；揭示了浅层土壤对温度波动和热交换的影响，浅层土壤是主要的蓄热区。在白天和夜间，土壤的有效蓄热深度和有效放热深度分别约为30 cm和25 cm，土壤日有效热转化率计算为48.1%。阐明了作物高度和通风开放度对温室通风降温性能的影响。当北壁通风口开度从0.6 m增加到1.8 m时，通风效率逐渐增加，作物高度为0.5 m时，作物区域的通风效率从1.40增加到2.09，作物高度为1.2 m时，作物区域的通风效率从3.10增加到5.06。本文为AFWG的年度使用提供了案例和依据。

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引用次数: 0

Comprehensive assessment of energy and environmental performance of CO2 heat pump system with dual indoor units for electric vehicles 电动汽车双室内机CO2热泵系统能源与环境性能综合评价

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-27 DOI: 10.1016/j.applthermaleng.2026.129975

Hongseok Choi , Seongmin Han , Sangmin Lee , Hoseong Lee

Recently, regulatory restrictions on per- and polyfluoroalkyl substances accelerated the transition toward environmentally friendly refrigerants. Among the available alternatives, CO₂ stood out due to its low global warming potential and zero ozone depletion potential. Although recent research increasingly focused on integrating CO₂ into automotive systems, comparative studies with widely used R-1234yf systems remained limited. Furthermore, the relatively lower cooling performance of CO₂ remained a significant challenge. This study addressed these gaps by implementing a dual-indoor-unit configuration to enhance the performance of CO₂ systems through experimental and simulation approaches. The system was evaluated under steady-state and transient conditions across various driving cycles and was compared with conventional R-1234yf heat pump systems. Key findings showed that, for the same power consumption, the dual-indoor-unit CO₂ system achieved a slightly higher cooling capacity than the R-1234yf system, whereas the single-indoor-unit CO₂ system provided only 77% of the R-1234yf system's cooling capacity. In heating mode, the dual-indoor-unit CO₂ system delivered approximately 2.3 times the heating capacity of the R-1234yf system. In driving cycle condition, the dual-indoor-unit CO₂ system matched the cooling performance of the R-1234yf system while reducing the heating time from 600 to 180 s. Energy efficiency improved by 29.0% in cooling mode and by 18.5% in heating mode, consequently extending the driving range. Furthermore, the environmental evaluation indicated a 20.1% reduction in life-cycle carbon dioxide emissions during cooling operation. These results supported the viability of the dual-indoor-unit CO₂ heat pump system as a sustainable solution for electric vehicles.

最近，对全氟烷基和多氟烷基物质的监管限制加速了向环保制冷剂的过渡。在现有的替代品中，二氧化碳因其低全球变暖潜能值和零臭氧消耗潜能值而脱颖而出。尽管最近的研究越来越关注于将二氧化碳集成到汽车系统中，但与广泛使用的R-1234yf系统的比较研究仍然有限。此外，二氧化碳相对较低的冷却性能仍然是一个重大挑战。本研究通过实验和模拟方法实现双室内单元配置，以提高CO2系统的性能，从而解决了这些差距。该系统在稳态和瞬态工况下进行了评估，并与传统的R-1234yf热泵系统进行了比较。主要研究结果表明，在相同的功耗下，双室内机CO2系统的制冷量略高于R-1234yf系统，而单室内机CO2系统的制冷量仅为R-1234yf系统的77%。在供暖模式下，双室内机CO2系统的供热能力约为R-1234yf系统的2.3倍。在行驶工况下，双室内机CO2系统的制冷性能与R-1234yf系统相当，同时将加热时间从600 s缩短至180 s。在冷却模式下，能源效率提高了29.0%，在加热模式下提高了18.5%，从而延长了行驶里程。此外，环境评价表明，在冷却运行期间，生命周期二氧化碳排放量减少了20.1%。这些结果支持了双室内单元二氧化碳热泵系统作为电动汽车可持续解决方案的可行性。

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引用次数: 0

Reduced-order model for predicting flow distribution in plate heat exchangers with novel header designs 新型集管板式换热器流场预测的降阶模型

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-27 DOI: 10.1016/j.applthermaleng.2026.130003

Mohammed Mizanur Rahman, André Bénard

Flow maldistribution in plate heat exchangers (PHEs) can significantly reduce thermal effectiveness and increase pressure losses. Optimizing the header shape has been shown to improve flow uniformity, motivating the development of predictive tools that enable header-shape optimization without reliance on computationally expensive CFD simulations. While prior analytical models have typically focused on individual header geometries, a unified mathematical framework applicable to multiple header configurations is still lacking. To address this gap, the present study introduces a unified reduced-order modeling framework for predicting flow distribution and pressure drop in U-type PHEs with non-uniform headers, including tapered, parabolic (concave and convex), and hyperbolic geometries. The mathematical formulation is based on a generalized one-dimensional nonlinear second-order ordinary differential equation derived from mass and momentum conservation, in which geometry-specific effects are incorporated through a header-area variation function. The numerical implementation is validated against analytical solutions, experimental data, and a discrete theoretical model. Parametric analysis reveals that the performance of different header configurations is strongly influenced by heat exchanger size and channel flow resistance: tapered and concave-parabolic headers can improve flow uniformity in small-scale systems over specific flow resistance regimes, whereas hyperbolic headers provide the most consistent improvement in large-scale systems at higher taper ratios. In contrast, parabolic convex headers typically deteriorate flow uniformity. The proposed framework provides a versatile and computationally efficient tool for predicting and optimizing flow distribution through header-geometry design, ultimately enhancing the performance, reliability, and thermal efficiency of PHEs.

板式换热器内部流动不均匀会显著降低换热器的热效率，增加压力损失。优化封头形状已被证明可以改善流动均匀性，这推动了预测工具的发展，使封头形状优化无需依赖计算成本高昂的CFD模拟。虽然先前的分析模型通常侧重于单个报头的几何形状，但仍然缺乏适用于多个报头配置的统一数学框架。为了解决这一差距，本研究引入了一个统一的降阶建模框架，用于预测带有非均匀头部的u型phe的流动分布和压降，包括锥形、抛物线（凹和凸）和双曲线几何形状。数学公式基于广义的一维非线性二阶常微分方程，该方程由质量和动量守恒推导而来，其中通过头部面积变化函数将几何特定效应纳入其中。数值实现通过解析解、实验数据和离散理论模型进行验证。参数分析表明，不同集管配置的性能受到热交换器尺寸和通道流动阻力的强烈影响：锥形和凹凸抛物线型集管可以改善特定流动阻力范围内小型系统的流动均匀性，而双曲型集管在较高锥度比下对大型系统的改善最为一致。相反，抛物面凸集管通常会破坏流动均匀性。所提出的框架提供了一个通用且计算效率高的工具，可以通过头部几何设计来预测和优化流动分布，最终提高phe的性能、可靠性和热效率。

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引用次数: 0

Spray and combustion characteristics of methanol dual-fuel engine for marine application 船用甲醇双燃料发动机的喷射和燃烧特性

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-27 DOI: 10.1016/j.applthermaleng.2026.129982

Seungho Yang , Hyunchun Park , Vallinayagam Raman , Balaji Mohan , Emre Cenker , Junseok Chang , Sungwook Park

Methanol is attracting increasing attention as a low-carbon fuel for marine engines; however, its low cetane number and high latent heat of vaporization pose challenges for stable ignition and combustion. In this study, the spray, ignition, and combustion characteristics of a diesel–methanol dual-fuel injection system were experimentally investigated using a marine-scale multi-hole injector in a constant-volume combustion chamber under engine-relevant conditions.

High-speed optical diagnostics were employed to analyze spray development, spray cone angle (SCA), ignition behavior, and heat release characteristics. The spray experiments showed that methanol consistently exhibits a larger SCA than diesel under all tested ambient pressures. At identical injection timings, the time-averaged SCA of methanol was approximately 0.2–13.4% larger than that of diesel, mainly due to its lower surface tension, which promotes enhanced breakup and radial dispersion despite its higher viscosity. In contrast, diesel exhibited up to 10% longer spray tip penetration owing to its higher density and momentum flux.

Combustion experiments demonstrated that dual-fuel ignition and heat release behavior are strongly governed by the dwell time between diesel pilot and methanol injections. Overlapping methanol injection with early diesel ignition increased the peak heat release rate by up to 8%, whereas delayed methanol injection resulted in smoother heat release and extended combustion duration. Ignition delay showed only minor variation across most conditions, indicating that diesel pilot injection controls global combustion initiation, while increasing methanol injection duration extended the overall combustion duration by up to 2 ms.

These results provide quantitative insight into spray–combustion interactions in diesel–methanol dual-fuel systems and highlight the importance of injection strategy optimization for stable and efficient low-carbon marine engine operation.

甲醇作为船用发动机的低碳燃料越来越受到关注；但其十六烷值低，汽化潜热高，对其稳定点火和燃烧提出了挑战。在与发动机相关的条件下，采用船用多孔喷油器在等体积燃烧室中对柴油-甲醇双燃料喷射系统的喷射、点火和燃烧特性进行了实验研究。采用高速光学诊断技术对喷淋发展、喷淋锥角、点火行为和放热特性进行了分析。喷雾实验表明，在所有测试的环境压力下，甲醇始终表现出比柴油更大的SCA。在相同的喷射时间下，甲醇的时间平均SCA比柴油高约0.2-13.4%，这主要是由于甲醇的表面张力较低，尽管其粘度较高，但它促进了破碎和径向分散。相比之下，柴油由于其更高的密度和动量通量，表现出高达10%的喷雾尖端穿透。燃烧实验表明，双燃料点火和放热行为受柴油先导和甲醇喷射之间停留时间的强烈影响。提前点火的重叠喷甲醇可使峰值热释放率提高8%，而延迟喷甲醇可使热释放更平稳，延长燃烧时间。点火延迟在大多数情况下变化很小，这表明柴油先导喷射控制了整体燃烧启动，而增加甲醇喷射持续时间可将整体燃烧持续时间延长2毫秒。这些结果为定量了解柴油-甲醇双燃料系统的喷燃相互作用提供了线索，并强调了喷射策略优化对稳定高效低碳船用发动机运行的重要性。

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引用次数: 0

Experimental and numerical investigation on heat transfer characteristics of the turbine blade leading edge with a Double-Wall cooling configuration featuring an oscillating jet 振荡射流双壁冷却涡轮叶片前缘换热特性的实验与数值研究

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-27 DOI: 10.1016/j.applthermaleng.2026.129989

Cunjin Zhang, Xiaojun Fan, Jiao Wang, Guangyao Yu, Junlin Cheng

To address the critical challenge that the turbine inlet temperature (TIT) in advanced gas turbines exceeds 1700 °C-far beyond the melting point of existing superalloys-this paper presents a systematic performance comparison of three double-wall cooling configurations. For the first time, a modular experimental platform equipped with interchangeable inserts (impingement, swirl, and oscillating jet) is employed together with a validated SST K-ω numerical model to ensure reliable and comparable results. The study innovatively demonstrates that oscillating jet cooling, through its inherent oscillatory sweeping mechanism, significantly enhances turbulent disturbance and effectively disrupts the thermal boundary layer. Under identical operating conditions, this configuration reduces the average leading-edge temperature of the blade by 4–15 K compared to conventional impingement and swirl cooling. This advantage is further amplified under higher temperature ratios (0.681–0.772) and elevated reynolds numbers (1.0 × 10⁵–1.7 × 10⁵). Moreover, the oscillating jet design eliminates the uneven temperature distribution typically caused by local coolant accumulation in traditional cooling structures. The findings underscore that even a modest reduction in operating temperature can substantially extend the service life of hot-section components. This work therefore provides a novel and effective research pathway for the thermal management of next-generation ultra-high-temperature gas turbine blades.

为了解决先进燃气轮机涡轮入口温度（TIT）超过1700°c的关键挑战-远远超过现有高温合金的熔点-本文提出了三种双壁冷却配置的系统性能比较。为了确保可靠和可比较的结果，我们首次采用了一个配备可互换刀片（撞击、涡流和振荡射流）的模块化实验平台，并采用了经过验证的SST K-ω数值模型。该研究创新性地证明了振荡射流冷却通过其固有的振荡扫掠机制，显著增强了湍流扰动，有效地破坏了热边界层。在相同的操作条件下，与传统的撞击和涡流冷却相比，这种配置将叶片的平均前缘温度降低了4 - 15k。在更高的温度比（0.681-0.772）和更高的雷诺数（1.0 × 105 - 1.7 × 105）下，这种优势进一步被放大。此外，振荡射流设计消除了传统冷却结构中由于局部冷却剂积聚而导致的温度分布不均匀的问题。研究结果强调，即使是适度降低工作温度，也可以大大延长热截面部件的使用寿命。本研究为下一代超高温燃气轮机叶片热管理提供了一条新颖有效的研究途径。

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引用次数: 0