Applied Thermal Engineering最新文献_第2页

Experimental and RSM-based optimization of CI engine performance using coconut shell gasified producer gas blend 椰壳气化产气混合物CI发动机性能的实验与rsm优化

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-31 DOI: 10.1016/j.applthermaleng.2026.129909

Pushpendu Kasaudhan, Jeewan Vachan Tirkey, Lawalesh Kumar Prajapati, Akash Giri, Priyaranjan Jena

The high energy density of diesel fuel (MJ/kg) makes it difficult to replace it entirely with alternative fuels for transportation and power generation. Hence, in order to enhance diesel fuel saving and reduce environmental pollution by waste to energy conversion, this paper deals with the generation of producer gas by coconut shell gasification and utilization in CI engine for power generation and emission mitigation. Despite significant progress, challenges still exist in conducting experimental pilot-scale studies and in optimizing the operating parameters of the integrated gasification–engine system for enhanced fuel savings and emission control. Accordingly, this study employs the experimental investigation of in situ Gasifier-Engine performance, especially the adoption of down draft air gasification and variable compression ratio (CR) engine. By integrating, the novelty is to identify the performance trends with operating parameter that lead to enhance replacement of diesel fuel and optimize the engine power and exhaust emission. Accordingly, the experiments were carried out on 50kWe(thermal)-pilot-scale downdraft gasifier with VCR engine under different loads, CR, and fuel injection pressure (FIP) for the assessment of performance characteristic. In experiments, maximum 63.81% diesel savings was obtained. Emission levels were notably low, with minimum values of 0.06 vol% CO, 12 ppm HC, 1.3 vol% CO₂, and 10 ppm NOₓ. Since, the trade-off performance nature has been observed with parametric variation, so, RSM was employed to optimize engine performance and emissions. The optimal operating conditions identified were a CR of 16, BP of 2.97 kW and FIP of 220 bars. Under these conditions, the predicted optimal outcomes included 56.13% diesel savings, 16.19% BTE, 0.075 vol% CO, 23.9 ppm HC, 2.65 vol% CO₂ and 30.3 ppm NOₓ. These results demonstrate the effectiveness of integrating coconut biomass gasification with CI engine technology and utilization of RSM tool for optimizing system performance in pilot scale.

柴油燃料的高能量密度（MJ/kg）使得它很难被运输和发电的替代燃料完全取代。因此，为了提高柴油的节油能力，减少废弃物对环境的污染，本文研究了椰子壳气化产生产气，并在CI发动机上利用，用于发电和减排。尽管取得了重大进展，但在进行中试规模的实验研究和优化集成气化发动机系统的操作参数以提高燃油节约和排放控制方面仍然存在挑战。因此，本研究采用原位气化炉-发动机性能的实验研究，特别是采用下风量空气气化和变压缩比（CR）发动机。通过集成，其新颖之处在于识别性能趋势与运行参数，从而提高柴油燃料的替换率，优化发动机功率和废气排放。为此，在50kWe（热）中试VCR发动机下吸式气化炉上进行了不同负荷、CR和燃油喷射压力（FIP）下吸式气化炉的性能特性评估。实验结果表明，该方法最大可节省63.81%的柴油。排放水平非常低，最小值为0.06 vol% CO, 12 ppm HC， 1.3 vol% CO₂和10 ppm NOₓ。由于在参数变化中观察到性能的权衡性质，因此采用RSM对发动机性能和排放进行优化。确定的最佳操作条件为CR为16，BP为2.97 kW， FIP为220 bar。在这些条件下，预测的最优结果包括柴油节约56.13%，BTE节约16.19%，CO节约0.075 vol%， HC节约23.9 ppm， CO₂节约2.65 vol%， NO节约30.3 ppmₓ。这些结果证明了将椰子生物质气化与CI发动机技术相结合以及利用RSM工具在中试规模上优化系统性能的有效性。

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引用次数: 0

Comprehensive energy, exergo-economic, and exergo-environmental (5E) assessment of a novel electric vehicle battery cooling system layout 一种新型电动汽车电池冷却系统布局的能源、消耗-经济和消耗-环境（5E）综合评估

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-30 DOI: 10.1016/j.applthermaleng.2026.129920

Mehdi Aliehyaei , Vincenzo Bianco , Mattia De Rosa

With the increasing energy density of batteries in electric vehicles (EVs), the design of battery thermal management systems with high energy performance and reduced economic and environmental costs has become a critical challenge. However, most previous studies have focused mainly on energy or exergy analyses, while comprehensive frameworks simultaneously incorporating economic and environmental aspects remain limited. In this study, a novel integrated thermal management system is developed to simultaneously control the temperature of the battery pack, cabin, and electric motor. The system is evaluated using a comprehensive five-dimensional (5E) framework, including energy, exergy, economic, exergo-economic, and exergo-environmental analyses. A detailed thermodynamic model of the proposed system is developed and validated against experimental data, showing deviations below 6% for key performance indicators. Under baseline operating conditions, the system achieves a coefficient of performance (COP) of 3.81, while the overall exergy efficiency is 5.5%, revealing a significant gap between energy quantity and energy quality. Exergy destruction analysis indicates that the evaporator and condenser are the dominant sources of irreversibility, with the condenser accounting for approximately 80% of the total capital cost. The specific cooling cost is estimated as 0.055 US$/kWh. Parametric analyses demonstrate that optimal thermodynamic and economic performance is obtained at mid-range battery state of charge (SOC

\approx

0.65–0.75). A comparative assessment of alternative refrigerants (R152a, R1234yf, and R513A) shows that R152a provides the highest COP (

\approx

4.0), whereas R1234yf offers superior environmental performance due to its ultra-low global warming potential. The results highlight the effectiveness of the proposed 5E framework in identifying dominant inefficiencies and trade-offs, and provide practical guidance for the thermodynamic design, refrigerant selection, and sustainable optimization of next-generation EV thermal management systems.

随着电动汽车电池能量密度的不断提高，设计高能量性能、低经济和环境成本的电池热管理系统已成为一项关键挑战。然而，大多数以前的研究主要集中在能源或火用分析，而同时纳入经济和环境方面的综合框架仍然有限。在这项研究中，开发了一种新的集成热管理系统，可以同时控制电池组，机舱和电动机的温度。该系统使用综合五维（5E）框架进行评估，包括能源、能源、经济、消耗-经济和消耗-环境分析。开发了该系统的详细热力学模型，并根据实验数据进行了验证，显示关键性能指标的偏差低于6%。在基线运行条件下，系统的性能系数（COP）为3.81，而总体的火用效率为5.5%，能源数量与能源质量之间存在较大差距。火能破坏分析表明，蒸发器和冷凝器是不可逆性的主要来源，冷凝器约占总资本成本的80%。具体冷却成本估计为0.055美元/千瓦时。参数分析表明，在电池荷电状态（SOC≈0.65 ~ 0.75）为中等时，获得了最佳的热力学和经济性能。R152a、R1234yf和R513A替代制冷剂的对比评估表明，R152a具有最高的COP(≈4.0)，而R1234yf由于其超低的全球变暖潜势而具有优越的环境性能。研究结果强调了5E框架在识别主要低效率和权衡方面的有效性，并为下一代电动汽车热管理系统的热力学设计、制冷剂选择和可持续优化提供了实用指导。

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引用次数: 0

Impact of injection timing and EGR on the combustion characteristics and emission behavior of DI diesel engines fueled with renewable alcohol based oxygenated blends 喷油正时和EGR对使用可再生酒精基含氧混合物的直喷柴油机燃烧特性和排放行为的影响

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-30 DOI: 10.1016/j.applthermaleng.2026.130023

K. Santhosh , Jayashish Kumar Pandey , B.E. Naveena , H.M. Shankara Murthy , B.M. Praveenkumara , R. Thirumaleswara Naik , N.R. Banapurmath , Solomon Jenoris Muthiya

Reducing carbon emissions from diesel engines has increased interest in oxygenated biofuels that offer cleaner combustion without engine modifications. Among higher alcohols, n-pentanol offers a promising combination of high oxygen content, renewable origin, and favorable combustion properties. This study experimentally demonstrates an additive-free strategy for operating a 40% n-pentanol/diesel blend (D60P40) in a common-rail direct injection diesel engine through the synergistic integration of advanced injection timing (15° BTDC) and exhaust gas recirculation (10% and 20%) across 20–80% engine loads. Advancing injection timing to 15° BTDC improved combustion, with an 8.85% increase in peak cylinder pressure and 15.19% higher heat release rate compared to diesel. Brake thermal efficiency (BTE) of D60P40 at this timing was only 2.36% lower than diesel, while retarded timing (9° BTDC) reduced BTE by 15.7%. EGR at 20% reduced NOx by 15.15%, but increased HC and CO due to thermal quenching. However, the inherent oxygen in pentanol helped limit these increases. The synergy of advanced injection timing with moderate EGR resolved the NOx–CO/HC trade-off, maintaining combustion efficiency while reducing emissions. These findings demonstrate a viable, retrofitting-free pathway for diesel engine decarbonization using oxygenated fuel blends, supporting global efforts toward cleaner and sustainable transport energy systems.

减少柴油发动机的碳排放增加了人们对含氧生物燃料的兴趣，这种生物燃料在不修改发动机的情况下提供更清洁的燃烧。在高等醇中，正戊醇具有高氧含量、可再生来源和良好的燃烧性能等优点。本研究通过实验验证了一种无添加剂策略，该策略可在共轨直喷柴油机中运行40%正戊醇/柴油混合气（D60P40），通过将先进的喷射正时（15°BTDC）和废气再循环（10%和20%）协同集成，在20-80%的发动机负载下运行。将喷射正时提前至15°BTDC改善了燃烧，与柴油相比，峰值气缸压力提高了8.85%，热释放率提高了15.19%。该正时D60P40的制动热效率（BTE）仅比柴油低2.36%，而减速正时（9°BTDC）使BTE降低了15.7%。20%的EGR使NOx减少15.15%，但由于热淬火，HC和CO增加。然而，戊醇中固有的氧有助于限制这些增加。先进的喷射正时与适度的EGR的协同作用解决了NOx-CO /HC的权衡，在保持燃烧效率的同时减少了排放。这些发现表明，使用含氧燃料混合物实现柴油发动机脱碳是一种可行的、无需改造的途径，支持全球朝着更清洁、可持续的交通能源系统发展的努力。

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引用次数: 0

Effect of alcohol type and blending ratio on sub-cooled and flash boiling combustion of gasoline-alcohol fuels 醇类和掺比对汽油-酒精燃料过冷和闪沸燃烧的影响

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-30 DOI: 10.1016/j.applthermaleng.2026.130059

Xuesong Li , Mingli Cui , Jinhong Fu , Guodong Wang , Bowei Yao , Hongchang Xu , Mohamed Almanzalawy

Substituting conventional fuels with clean fuels such as methanol, ethanol, or butanol has the potential to achieve carbon neutrality goals. This study systematically investigates the effects of alcohol fuels on the combustion and emissions of gasoline under low pressure of 60 kPa and rich conditions of 1.25, representing cold-start relevant environments. Methanol was tested at different volume concentrations of 25%, 50%, and 75% with gasoline, while ethanol and butanol were compared to methanol at a 50% concentration. Experiments were conducted in a constant volume combustion chamber under sub-cooled conditions at a temperature of 30 °C and under flash boiling conditions at a superheat index of 0.3. Alcohols with shorter carbon chains or lower concentrations of methanol increased the flame propagation speed by 14.5% with 50% of methanol. Fourier transform infrared spectroscopy (FTIR) analysis showed reductions in unburned hydrocarbons, mono-aromatic compounds, and nitrogen oxide emissions by 38.6%, 56.1%, and 7.7%, respectively, although formaldehyde formation was increased by 200%. An inflection point was observed at M25 for all emissions. Soot morphology and nanostructure analysis revealed that soot formation is suppressed and oxidation is increased. Spray morphology indicated that flash boiling improved atomization, while flame images confirmed that flash boiling accelerated flame propagation, particularly with shorter alcohols or lower percentages. Flash boiling enhanced carbon oxidation by reducing unburned hydrocarbons and monocyclic aromatic compounds, with a corresponding increase in carbon oxide formation, indicating improved combustion in terms of oxidation completeness. Furthermore, flash boiling suppressed the formation of fuel-rich zones, thereby reducing soot generation from all blends (with a 51.3% reduction in the size of the soot aggregates), even under rich combustion conditions. This work establishes a unified framework linking fuel molecular structure and flash-boiling atomization to combustion behavior and soot formation in alcohol-fueled systems.

用甲醇、乙醇或丁醇等清洁燃料替代传统燃料有可能实现碳中和目标。本研究系统研究了在低压60 kPa和富工况1.25条件下，代表冷启动相关环境下，酒精燃料对汽油燃烧和排放的影响。甲醇在25%、50%和75%的不同体积浓度下与汽油进行了测试，乙醇和丁醇在50%的浓度下与甲醇进行了比较。实验在定容燃烧室中进行，温度为30℃，过冷条件下，闪沸条件下，过热指数为0.3。碳链较短或甲醇浓度较低的醇在甲醇含量为50%时，火焰传播速度提高14.5%。傅里叶变换红外光谱（FTIR）分析显示，未燃烧的碳氢化合物、单芳香族化合物和氮氧化物的排放量分别减少了38.6%、56.1%和7.7%，尽管甲醛的生成增加了200%。在M25处观测到所有排放的拐点。烟尘形貌和纳米结构分析表明，烟尘的形成受到抑制，氧化作用增强。喷雾形貌表明，闪沸改善了雾化效果，而火焰图像证实，闪沸加速了火焰的传播，特别是在较短的醇或较低的百分比下。闪沸通过减少未燃烧的碳氢化合物和单环芳香族化合物来增强碳氧化，相应增加了碳氧化物的形成，表明在氧化完整性方面改善了燃烧。此外，闪速沸腾抑制了富燃料区的形成，从而减少了所有混合物的煤烟生成（煤烟聚集体的尺寸减少了51.3%），即使在富燃烧条件下也是如此。这项工作建立了一个统一的框架，将燃料分子结构和闪沸雾化与酒精燃料系统的燃烧行为和烟灰形成联系起来。

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引用次数: 0

Investigation on thermal behavior during leakage from subsurface hydrogen pipelines 地下氢气管道泄漏过程的热行为研究

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-30 DOI: 10.1016/j.applthermaleng.2026.129979

Haobo Jia , Jingmin Zhang , Zhen Pan , Wenhui Song , Shuaiqi Liang

Motivated by the catastrophic hazards associated with leaks from buried hydrogen pipelines, this work systematically investigates the dynamics of leakage and thermal evolution using numerical simulation. Results reveal a high-pressure zone above the leak hole and gradual horizontal pressure attenuation. The velocity field exhibits a mushroom-like structure under subsonic flow. Hydrogen diffusion is buoyancy-dominated, forming concentric horizontal concentration profiles and reaching the atmosphere vertically within thousands of seconds, while diffusion delays occur below the pipeline due to soil barriers. Pipeline pressure and leak diameter synergistically enhance Joule-Thomson cooling and the injection of cold gas; their interaction with low porosity leads to an exponential expansion of the low-temperature zone. Soil temperature affects only initial conditions; leakage direction and burial depth show minimal impact. A validated steady-state temperature model (Eq. 10) achieved R² = 0.99 (error < 3%) across 13 cases. A novel localization method based on temperature gradient fitting (Eq. 11) achieved a 0.1% error with R² = 0.95. Key risk factors include pressure, leak diameter, and porosity. The models provide critical risk assessment tools, with future work integrating multi-physics and machine learning for broader applicability.

由于埋地氢气管道泄漏带来的灾难性危害，本研究采用数值模拟方法系统地研究了泄漏和热演化的动力学。结果表明，泄漏孔上方存在高压区，水平压力逐渐衰减。亚音速下的速度场呈蘑菇状结构。氢气扩散以浮力为主导，形成同心的水平浓度曲线，在数千秒内垂直到达大气，而管道下方由于土壤屏障而发生扩散延迟。管道压力和泄漏直径协同增强焦耳-汤姆逊冷却和冷气体的注入；它们与低孔隙度的相互作用导致低温区呈指数扩展。土壤温度只影响初始条件；渗漏方向和埋深影响最小。经过验证的稳态温度模型（Eq. 10）在13种情况下实现R2 = 0.99（误差<； 3%）。基于温度梯度拟合（Eq. 11）的定位方法误差为0.1%,R2 = 0.95。关键的风险因素包括压力、泄漏直径和孔隙度。这些模型提供了关键的风险评估工具，未来的工作将集成多物理场和机器学习，以获得更广泛的适用性。

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引用次数: 0

A dual-strategy thermal management system for lithium-ion battery: integrating immersion cooling with shape-stable phase change materials 锂离子电池的双策略热管理系统：融合浸没冷却与形状稳定相变材料

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-30 DOI: 10.1016/j.applthermaleng.2026.130001

Jie Mei , Guoqing Shi , Mingyi Chen , Bohong Wang , Dingding Yang , Qing Li , Yi Zhang , Weiguang An

The rapid expansion of electric-vehicle deployment has accelerated lithium-ion battery adoption, yet overheating and intra-pack temperature imbalance have emerged as critical barriers. This paper designs an efficient hybrid thermal management system and employs experimental methods to analyze and optimize its thermal management performance. Shape-stable phase-change materials (SPCMs) were developed, with the composition optimized through systematic thermophysical analysis. Charge–discharge tests validated that the prepared SPCM delivers effective thermal management, reducing both the maximum temperature and temperature difference across the battery pack by approximately 28%. To further improve temperature uniformity across the battery pack and maintain thermal control under extreme high-temperature conditions, the parameters of the hybrid cooling system combining SPCM3 and immersion liquid cooling were optimized. The results shows that the hybrid cooling system reduces T_max to 35.8 °C with a ΔT_max of only 1.9 °C at a 3C discharge rate. The heat transfer mechanism between the battery and the SPCM was elucidated, demonstrating that immersion liquid cooling improves the heat transfer efficiency of the SPCM. These findings provide valuable insights for designing efficient hybrid thermal management systems for lithium-ion batteries.

电动汽车的快速扩张加速了锂离子电池的普及，但过热和电池组内部温度不平衡已成为关键障碍。本文设计了一种高效的混合式热管理系统，并采用实验方法对其热管理性能进行了分析和优化。研制了形状稳定相变材料（spcm），并通过系统热物理分析优化了其组成。充放电测试证实，制备的SPCM提供了有效的热管理，将电池组的最高温度和温差降低了约28%。为了进一步提高整个电池组的温度均匀性，并在极端高温条件下保持热控制，对SPCM3与浸没式液冷相结合的混合冷却系统参数进行了优化。结果表明，在3C放电速率下，混合冷却系统将Tmax降低到35.8°C， ΔTmax仅为1.9°C。分析了电池与SPCM之间的换热机理，表明浸没式液体冷却提高了SPCM的换热效率。这些发现为设计高效的锂离子电池混合热管理系统提供了有价值的见解。

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引用次数: 0

Numerical simulation of heat transfer phenomena and influencing factors between deep and shallow geothermal reservoirs 深层与浅层地热储层换热现象及影响因素的数值模拟

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-29 DOI: 10.1016/j.applthermaleng.2026.130038

Liu Junrong , Liu Wenqiang , Wu Xingru , Zhang Yaping

To address the challenge of aligning seasonal heat supply with demand, this study delves into four distinct operational modes: (I) deep recharge – shallow production; (II) shallow recharge - deep production; (III) simultaneous deep and shallow recharge - shallow production; and (IV) simultaneous deep and shallow recharge - deep production.By examining these four operational modes, we investigate how recharge intensity and temperature impact heat production efficiency and thermal imbalance within coupled deep and shallow geothermal reservoirs. Our findings reveal that, across all four modes, a combination of high recharge temperature and low recharge intensity effectively mitigates the decrease in formation temperature. Higher recharge temperature reduces thermal drawdown by decreasing the fluid–rock temperature contrast, while lower recharge intensity limits advective heat depletion. Notably, when CO₂ serves as the circulating fluid, the rate and extent of formation temperature decline are less pronounced compared to when water is used. This enhanced thermal retention indicates that CO₂ is a favorable working-fluid option for long-term heat extraction under moderate thermal loads.

为了解决使季节性供热与需求保持一致的挑战，本研究深入研究了四种不同的运行模式：(1)深度补给-浅层生产；（二）浅层补给-深层生产；（三）深浅同时补给——浅生产；（四）深部和浅层同时补给-深部生产。通过对这四种运行模式的考察，研究了回填强度和温度对深层和浅层耦合地热储层产热效率和热不平衡的影响。我们的研究结果表明，在所有四种模式中，高回灌温度和低回灌强度的组合有效地缓解了地层温度的下降。较高的回灌温度通过降低流体-岩石温度对比来降低热降，而较低的回灌强度限制了对流热消耗。值得注意的是，当CO2作为循环流体时，地层温度下降的速度和程度不如用水时明显。这种增强的热保留表明，在中等热负荷下，CO₂是长期热提取的有利工作流体选择。

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引用次数: 0

Thermal characteristic analysis and performance optimization of a novel heating boiler based on a porous media model 基于多孔介质模型的新型供热锅炉热特性分析及性能优化

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-29 DOI: 10.1016/j.applthermaleng.2026.130035

Zong-bao Li , Yue Yu , Li Jia , Ya-wen Wu , Peng Cheng , Zhen Zhang , Zi-kuo Li , Chu-hao Fan , Xue-mao Guo

Premixed low-nitrogen heating boilers face challenges such as suboptimal thermal efficiency, tube rupture risks, and difficulties in high-temperature experimental analysis. To address these issues, this study employs an innovative approach by integrating a porous media model for the metal fiber burner and finned tubes, enabling efficient three-dimensional numerical simulation of an asymmetric four-pass heat exchanger. Simulations across a range of excess air coefficients (α = 1.1–1.6) reveal that α = 1.3 represents the optimal condition, achieving a thermal efficiency of 94.6%, NO_X emissions of only 5.95 mg/m³, and a stable finned-tube wall temperature of approximately 570 K. To further overcome problems of uneven burner flames, inefficient waste heat utilization, and poor flue gas exhaust, a comprehensive structural optimization strategy is proposed and validated. This includes a 4-zone perforated plate design for balanced fuel distribution, the integration of a gas-water heat exchanger for waste heat recovery, and the replacement of the single flue gas outlet with dual 120 mm outlets. These modifications collectively increase the boiler thermal efficiency to 97.1%, reduce the flue gas exhaust temperature from 365.3 K to 357.8 K, alleviate local high temperatures, and significantly improve flue gas flow uniformity. This work provides a validated framework for the performance enhancement and engineering application of efficient, low-emission heating boilers.

预混式低氮供热锅炉面临着热效率不理想、管道破裂风险、高温实验分析困难等挑战。为了解决这些问题，本研究采用了一种创新的方法，将金属纤维燃烧器和翅片管的多孔介质模型集成在一起，实现了非对称四通道换热器的高效三维数值模拟。在过量空气系数（α = 1.1-1.6）范围内的模拟表明，α = 1.3代表最佳条件，实现热效率为94.6%，NOX排放量仅为5.95 mg/m3，稳定的翅片管壁温度约为570 K。为进一步解决燃烧器火焰不均匀、余热利用效率低、烟气排放差等问题，提出并验证了综合结构优化策略。这包括一个用于平衡燃料分配的四区穿孔板设计，一个用于废热回收的气水热交换器的集成，以及用两个120毫米出口取代单个烟道气出口。这些改造共同使锅炉热效率提高到97.1%，烟气排气温度从365.3 K降低到357.8 K，缓解了局部高温，烟气流动均匀性明显提高。这项工作为高效、低排放供热锅炉的性能提升和工程应用提供了一个有效的框架。

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引用次数: 0

Multi-objective optimization of thermo-hydraulic performance in triangular duct solar air heaters using machine learning models 基于机器学习模型的三角风道太阳能空气加热器热水力性能多目标优化

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-29 DOI: 10.1016/j.applthermaleng.2026.130018

S.K. Gugulothu , Praveen Barmavatu

This study presents a coupled Computational Fluid Dynamics (CFD)–Machine Learning Algorithm (MLA) framework to optimize the thermo-hydraulic performance of a triangular duct solar air heater (SAH) with rounded corners and artificial roughness elements. A CFD-generated dataset of 60 cases was used to train and evaluate six supervised regression models—Linear Regression (LR), k-Nearest Neighbor (KNN), Random Forest (RF), Stochastic Gradient Descent Regressor (SGDR), Multilayer Perceptron (MLP), and Decision Tree (DT)—based on Nusselt number (Nu) and friction factor (f). Among these, DT achieved the highest accuracy for Nu prediction (R² = 0.9988 for training and 0.9967 for testing), while LR performed best for f (R² = 0.8924 for training and 0.9273 for testing). GridSearchCV-based hyperparameter tuning further improved model robustness, enabling predictions closely aligned with CFD results. Subsequent optimization using Design Expert confirmed negligible deviation between MLA-based and CFD-based optimal inputs, validating the surrogate modelling approach. The optimal configuration z'/e = 10, Rc ≈ 0.335, and Re ≈ 21,000—yielded enhanced heat transfer with manageable frictional penalties. These findings highlight the ability of ML to replicate CFD outcomes at a fraction of the computational cost, providing a scalable and efficient strategy for rapid design and optimization of solar thermal systems.

本文提出了一种计算流体力学(CFD) -机器学习算法（MLA）耦合框架，以优化具有圆角和人工粗糙度元素的三角形风道太阳能空气加热器（SAH）的热工性能。基于Nusselt数（Nu）和摩擦因子(f)，使用cfd生成的60例数据集训练和评估6种监督回归模型——线性回归（LR）、k近邻回归（KNN）、随机森林（RF）、随机梯度下降回归（SGDR）、多层感知器（MLP）和决策树（DT）。其中DT对Nu的预测准确率最高（训练R2 = 0.9988，测试R2 = 0.9967）， LR对f的预测准确率最高（训练R2 = 0.8924，测试R2 = 0.9273）。基于gridsearchcv的超参数调优进一步提高了模型的鲁棒性，使预测与CFD结果紧密一致。随后使用Design Expert进行的优化证实，基于mla和基于cfd的最优输入之间的偏差可以忽略不计，从而验证了代理建模方法。最佳配置z′/e = 10, Rc≈0.335，Re≈21000 -产生了更强的传热和可控的摩擦损失。这些发现突出了ML以很小的计算成本复制CFD结果的能力，为太阳能热系统的快速设计和优化提供了可扩展和高效的策略。

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引用次数: 0

Influence of reduced gravity on liquid helium pool boiling heat transfer 失重对液氦池沸腾传热的影响

IF 6.9 2区工程技术 Q2 ENERGY & FUELS

Applied Thermal Engineering

Pub Date : 2026-01-29 DOI: 10.1016/j.applthermaleng.2026.129910

Simon Bagnis , Bertrand Baudouy , Steffen Krämer , Clément Lorin , Hugo Reymond

Through a series of experimental sessions, we have characterized pool boiling heat transfer in liquid helium (LHe) around saturation (4.2 K) under reduced gravity conditions ranging from 0.02g to 1g using magnetic forces. The magnetic forces were generated using a 30 T resistive magnet. First, the experimental results confirm and strengthen previous measurements regarding the critical heat flux dependency with respect to reduced gravity. Secondly and more importantly, they provide Nukiyama’s curves for liquid helium at 4.2 K and 1 bar at various reduced gravity levels (

\approx

0.02g,

\approx

0.25g,

\approx

0.5g, 1g). Measurements of both nucleate and film boiling regimes are studied and compared with considerations of their theoretically predicted gravity-dependent evolution. The measurements do not show significant degradation of the heat transfer coefficient under reduced gravity only the critical heat flux seems to be drastically impacted by the gravity level.

通过一系列的实验，我们利用磁力表征了液氦（LHe）在饱和状态（4.2 K）下，在失重状态下（从0.02g到1g）的池沸腾传热。磁力是用30t的电阻磁铁产生的。首先，实验结果证实并加强了先前关于临界热通量与重力减小相关的测量结果。其次，更重要的是，他们提供了液氦在4.2 K和1 bar下在各种降低重力水平（≈0.02g,≈0.25g,≈0.5g, 1g）下的Nukiyama曲线。研究了核沸腾和膜沸腾两种沸腾状态的测量结果，并对其理论预测的重力依赖演化进行了比较。测量结果没有显示重力降低时传热系数的显著降低，只有临界热通量似乎受到重力水平的剧烈影响。

{"title":"Influence of reduced gravity on liquid helium pool boiling heat transfer","authors":"Simon Bagnis , Bertrand Baudouy , Steffen Krämer , Clément Lorin , Hugo Reymond","doi":"10.1016/j.applthermaleng.2026.129910","DOIUrl":"10.1016/j.applthermaleng.2026.129910","url":null,"abstract":"<div><div>Through a series of experimental sessions, we have characterized pool boiling heat transfer in liquid helium (LHe) around saturation (4.2 K) under reduced gravity conditions ranging from 0.02g to 1g using magnetic forces. The magnetic forces were generated using a 30 T resistive magnet. First, the experimental results confirm and strengthen previous measurements regarding the critical heat flux dependency with respect to reduced gravity. Secondly and more importantly, they provide Nukiyama’s curves for liquid helium at 4.2 K and 1 bar at various reduced gravity levels (<span><math><mo>≈</mo></math></span>0.02g, <span><math><mo>≈</mo></math></span>0.25g, <span><math><mo>≈</mo></math></span>0.5g, 1g). Measurements of both nucleate and film boiling regimes are studied and compared with considerations of their theoretically predicted gravity-dependent evolution. The measurements do not show significant degradation of the heat transfer coefficient under reduced gravity only the critical heat flux seems to be drastically impacted by the gravity level.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 129910"},"PeriodicalIF":6.9,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146096195","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}

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