Case Studies in Thermal Engineering最新文献_第2页

Effects of variable Miller cycle on combustion performance and fuel economy of highly intensified diesel engines 可变米勒循环对高强化柴油机燃烧性能和燃油经济性的影响

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107656

Jinqun Zhang , Zixing Gan , Shijie Wang , Niancheng Guo , Zongfa Xie

The Miller cycle has received increasing attention and application in the field of diesel engines. However, studies that have addressed the practical application of the variable Miller cycle in multi-cylinder diesel engines remain limited. Here, a six-cylinder highly intensified heavy-duty diesel engine equipped with a high geometric compression ratio and two-stage turbocharger was employed to evaluate a self-designed fully hydraulic variable valve system (FHVVS). This novel system enables early intake valve closure, allowing diesel engine operation in both Diesel and Miller cycle modes. Comparative experiments on a performance test bench were conducted to assess the effects of the variable Miller cycle on combustion and intake characteristics. Combustion matching was achieved by optimizing the injection advance angle. A fuel economy comparison between operating modes suggested that the Miller cycle effectively reduced pumping losses compared with the Diesel cycle, lowering pumping mean effective pressure (PMEP) by an average of 71.5 kPa (60.2%) at 1400 rpm. The Miller cycle also decreased maximum combustion pressures, reducing the mechanical load as well as creating highly favorable conditions for optimal matching of the crank angle at 50% heat release, thus improving combustion performance in highly intensified diesel engines. By improving pumping losses and reasonably matching combustion parameters, the Miller cycle substantially extended the low fuel consumption range at medium speed and medium-to-high load. Compared with the Diesel cycle, the Miller cycle reduced the average fuel consumption rate by 8.5 g/(kW·h), a 4.0% decrease. By ensuring rapid and smooth conversion between operating modes (conversion time <0.075 s), the proposed FHVVS plays an important role in improving the instantaneous acceleration performance of heavy-duty vehicles powered by highly intensified diesel engines under low speed and low load.

米勒循环在柴油机领域得到了越来越多的关注和应用。然而，针对可变米勒循环在多缸柴油机中的实际应用的研究仍然有限。研究人员利用一台配备高几何压缩比和两级涡轮增压器的六缸高强度重型柴油发动机，对自行设计的全液压可变气门系统（FHVVS）进行了评估。这种新颖的系统可以提前关闭进气阀，使柴油机在柴油和米勒循环模式下都能运行。在性能测试台上进行了对比实验，以评估可变米勒循环对燃烧和进气特性的影响。通过优化喷射提前角实现燃烧匹配。两种运行模式的燃油经济性比较表明，与柴油循环相比，Miller循环有效地减少了泵送损失，在1400转/分时，泵送平均有效压力（PMEP）平均降低了71.5 kPa（60.2%）。Miller循环还降低了最大燃烧压力，减少了机械负荷，并为50%放热时曲柄角的最佳匹配创造了非常有利的条件，从而改善了高度强化的柴油发动机的燃烧性能。通过改善泵送损失和合理匹配燃烧参数，Miller循环大大延长了中速中高负荷下的低油耗范围。与柴油循环相比，米勒循环平均油耗降低8.5 g/(kW·h)，降低4.0%。FHVVS保证了工作模式间的快速平稳转换（转换时间<；0.075 s），对于提高高强化柴油机驱动的重型车辆在低速低负荷下的瞬时加速性能具有重要作用。

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引用次数: 0

Experimental study on thermal decomposition and kinetic characteristics of coal in O2/CO2/N2 atmospheres with various CO2/N2 blend ratios 不同CO2/N2混合比下煤在O2/CO2/N2气氛中的热分解及动力学特性实验研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107653

Chunlei Wu , Jing Li , Bobo Shi , Yong Xue

This study explores the inhibitory mechanisms of CO₂/N₂ ratios and O₂ concentrations on coal oxidative pyrolysis to provide theoretical insights into the use of CO₂-N₂ mixed inert gas in goaf fire prevention. Thermogravimetric analysis (TGA) was employed to investigate coal pyrolysis under varying coal metamorphism, heating rates, O₂ concentrations, and CO₂/N₂ ratios. Results show that increasing the heating rate raises characteristic temperatures and enhances the oxidative pyrolysis in DX coal. The apparent activation energies of DX, TX, and YCW coals exhibit an initial increase followed by a decrease as conversion rates rise, peaking at 0.15 conversion. At a constant O₂ concentration, the apparent activation energy is highest when the CO₂/N₂ ratio is 4:6, suggesting more energy is required and oxidation is more effectively inhibited. Conversely, increasing O₂ concentration leads to a linear decrease in the apparent activation energies, indicating enhanced coal oxidative pyrolysis.

本研究探讨CO2/N2比和O2浓度对煤氧化热解的抑制机制，为CO2-N2混合惰性气体在采空区防火中的应用提供理论依据。采用热重分析（TGA）研究了煤在不同变质作用、升温速率、O2浓度和CO2/N2比下的热解过程。结果表明，升温速率的提高提高了特征温度，促进了DX煤的氧化热解。随着转化率的升高，DX、TX和YCW煤的表观活化能先升高后降低，在转化率为0.15时达到峰值。在一定的O2浓度下，当CO2/N2比为4:6时，表观活化能最高，说明需要更多的能量，更有效地抑制氧化。相反，随着O2浓度的增加，表观活化能呈线性降低，表明煤的氧化热解能力增强。

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引用次数: 0

Numerical and SPIV experimental investigation of a novel arc bifurcation insert for synergistic heat transfer enhancement in tubes 一种新型管内协同强化换热电弧分叉插片的数值与SPIV实验研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107660

Qinglin Du, Gen Ou, Zhichun Liu, Wei Liu

The application of longitudinal swirl generators (LSGs) has received considerable attention in recent years as an effective approach for heat transfer enhancement with low consumption. This study proposes a novel insert—bifurcated arc semi-pipes (BASPs)—by introducing a curved bifurcation structure into conventional LSGs, designed to achieve synergistic heat transfer enhancement. The primary semi-pipes generate multiple longitudinal swirling flows to improve temperature uniformity of core flow region, while the curved bifurcations generate local disturbances near wall hotspots, thus improving wall temperature uniformity, with minimal mutual interference between these two mechanisms. The heat transfer enhancement mechanisms of BASPs under laminar conditions are explored via computational fluid dynamics (CFD) simulations and stereoscopic particle image velocimetry (SPIV) experiments. The complex effects of five geometric parameters (slant angle α, branching distance h, branching angle β, curvature coefficient ε, and pitch P) on the thermo-hydraulic performance and irreversibility are systematically examined. The Nusselt number increases to 3.34–9.47 times that of the smooth tube, while the friction factor rises to 2.59–10.23 times. The maximum performance evaluation criteria (PEC) reaches 4.63. Furthermore, geometric parameters of BASPs are optimized based on the dissipation minimization principle. A design on the obtained Pareto front achieves a Nusselt number enhancement of 8.71 times, surpassing all training cases under the same Reynolds number, and the compromise solution also attains a PEC value of 4.12, confirming the theoretical guidance provided by the dissipation minimization principle.

纵向旋流发生器作为一种低能耗强化传热的有效方法，近年来得到了广泛的应用。本研究提出了一种新的插入分叉弧半管(BASPs) -通过在传统的LSGs中引入弯曲的分叉结构，旨在实现协同传热增强。主半管产生多个纵向旋流，提高了岩心流区温度均匀性，弯曲分岔在壁面热点附近产生局部扰动，提高了壁面温度均匀性，两种机制相互干扰最小。通过计算流体力学（CFD）模拟和立体粒子图像测速（SPIV）实验，探讨了层流条件下BASPs的强化传热机理。系统地考察了5个几何参数（倾斜角α、分支距离h、分支角β、曲率系数ε和节距P）对热液性能和不可逆性的复杂影响。努塞尔数增加到光滑管的3.34 ~ 9.47倍，摩擦系数增加到2.59 ~ 10.23倍。PEC （performance evaluation criteria）最高可达4.63。在此基础上，基于耗散最小化原理对其几何参数进行了优化。在得到的Pareto front上设计的Nusselt数增强了8.71倍，超过了相同雷诺数下的所有训练案例，折衷解的PEC值也达到了4.12，证实了耗散最小化原理的理论指导。

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引用次数: 0

Performance evaluation of two-phase direct-to-chip liquid cooling combined with air cooling for data centers 数据中心两相直接对片液冷与空冷相结合的性能评估

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107650

Vahid Ebrahimpour Ahmadi, Henrik A. Barestrand, Jon Summers, Cagatay Yilmaz

The increasing power density of modern data centers presents significant cooling challenges, as traditional air cooling methods approach their physical and economic limits for artificial intelligence and high-performance computing applications. Integrating direct liquid cooling with existing air-cooled infrastructures offers a promising solution to enhance thermal management and energy efficiency. This study investigates the performance of a hybrid cooling system employing two-phase direct-to-chip liquid cooling, retrofitted to nine air-cooled Open Compute Project servers equipped with Intel Xeon E5 v3 microprocessors. Experiments were conducted in a controlled server wind tunnel environment to evaluate thermal and power characteristics under inlet air temperatures ranging from 25 to 45 °C and varying IT workloads. Results demonstrate substantial CPU temperature reductions, from 93 °C with air cooling to 56 °C with hybrid cooling at 25 °C inlet under full load. As inlet temperature increases on the air side, the two-phase system captures a greater proportion of the heat load, reaching up to 90% at 45 °C. These findings demonstrate the potential of hybrid cooling to extend the thermal envelope of existing air-cooled data centers beyond conventional ASHRAE A1 class limits, reduce operational costs, and facilitate waste heat recovery for secondary applications.

现代数据中心不断增加的功率密度带来了巨大的冷却挑战，因为传统的空气冷却方法已经接近人工智能和高性能计算应用的物理和经济极限。将直接液体冷却与现有的风冷基础设施相结合，为加强热管理和能源效率提供了一个有前途的解决方案。本研究研究了一种采用两相直接对芯片液冷的混合冷却系统的性能，该系统被改造为9台配备英特尔至强E5 v3微处理器的风冷开放计算项目服务器。实验在受控的服务器风洞环境中进行，以评估进气温度为25至45°C以及不同IT工作负载下的热和功率特性。结果表明，CPU温度大幅降低，从空气冷却时的93°C降至全负荷进口25°C时的56°C混合冷却。随着空气侧入口温度的升高，两相系统捕获了更大比例的热负荷，在45°C时达到90%。这些发现证明了混合冷却的潜力，可以将现有风冷数据中心的热包线扩展到传统的ASHRAE A1级限制之外，降低运营成本，并促进废热回收用于二次应用。

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引用次数: 0

A centralized smoke exhaust method using branch tunnel in bifurcated tunnel fires: Impact on maximum ceiling temperature in main tunnel 分叉隧道火灾中分支隧道集中排烟方法对主隧道最高顶温的影响

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107652

Wei Cong , Yujie Ma , Kun He , Shaojie Zhang , Wei Peng

Bifurcated tunnels are widely used in urban road and metro systems, yet their branching geometry complicates smoke control compared with single-line tunnels. This study numerically investigates the maximum ceiling temperature (MCT) in the main tunnel when a centralized exhaust vent is arranged in the branch tunnel, considering different fire locations, exhaust velocities (

V_{e}

), and heat release rates. Results show that as

V_{e}

increases from 0 to 8 m/s, the MCT decreases by approximately 50 %. The influence of fire location depends on the exhaust intensity: under weak exhaust (

V_{e} = 2 m / s

), the MCT decreases as the fire moves farther from the junction due to reduced smoke accumulation and recirculation near the bifurcation, whereas under strong exhaust (

V_{e} \geq 4 m / s

, satisfying

V_{e} A_{e} / A_{m} \geq 1.6 m / s

) the MCT becomes weakly dependent on fire location when the smoke layer has developed into the one-dimensional flow before reaching the junction. The flame exhibits a longitudinal tilt toward the junction for non-junction fires and lateral guidance into the branch for junction fires. Based on the flame tilting characteristics, an empirical correlation incorporating exhaust volume, tunnel geometry and fire parameters is developed to predict the MCT under strong exhaust. A comparison indicates that centralized smoke exhaust better protects the downstream region, while longitudinal ventilation is more effective in reducing smoke accumulation near the fire source.

分岔隧道广泛应用于城市道路和地铁系统中，但与单线隧道相比，分岔隧道的几何结构使其烟雾控制复杂化。考虑不同的火灾位置、排风速度和放热速率，对在支洞设置集中排风口时，主洞的最大顶温（MCT）进行数值研究。结果表明，当Ve从0增加到8 m/s时，MCT降低约50%。火灾位置的影响受排气强度的影响，弱排气（Ve=2m/s）下，由于分叉附近的烟雾积累和再循环减少，随着火灾离接点越远，MCT越低，而强排气（Ve≥4m/s，满足VeAe/Am≥1.6m/s）下，当烟雾层在到达接点之前发展成一维流时，MCT对火灾位置的依赖性减弱。火焰表现出纵向倾斜向结的非结火和横向引导到分支的结火。基于火焰倾斜特性，建立了结合排气量、隧道几何形状和火灾参数的经验关联模型，预测了强排气量下的MCT。对比表明，集中排烟能更好地保护下游区域，而纵向通风能更有效地减少火源附近的烟雾积聚。

{"title":"A centralized smoke exhaust method using branch tunnel in bifurcated tunnel fires: Impact on maximum ceiling temperature in main tunnel","authors":"Wei Cong , Yujie Ma , Kun He , Shaojie Zhang , Wei Peng","doi":"10.1016/j.csite.2026.107652","DOIUrl":"10.1016/j.csite.2026.107652","url":null,"abstract":"<div><div>Bifurcated tunnels are widely used in urban road and metro systems, yet their branching geometry complicates smoke control compared with single-line tunnels. This study numerically investigates the maximum ceiling temperature (MCT) in the main tunnel when a centralized exhaust vent is arranged in the branch tunnel, considering different fire locations, exhaust velocities (<span><math><mrow><msub><mi>V</mi><mi>e</mi></msub></mrow></math></span>), and heat release rates. Results show that as <span><math><mrow><msub><mi>V</mi><mi>e</mi></msub></mrow></math></span> increases from 0 to 8 m/s, the MCT decreases by approximately 50 %. The influence of fire location depends on the exhaust intensity: under weak exhaust (<span><math><mrow><msub><mi>V</mi><mi>e</mi></msub><mo>=</mo><mn>2</mn><mspace></mspace><mi>m</mi><mo>/</mo><mi>s</mi></mrow></math></span>), the MCT decreases as the fire moves farther from the junction due to reduced smoke accumulation and recirculation near the bifurcation, whereas under strong exhaust (<span><math><mrow><msub><mi>V</mi><mi>e</mi></msub><mo>≥</mo><mn>4</mn><mspace></mspace><mi>m</mi><mo>/</mo><mi>s</mi></mrow></math></span>, satisfying <span><math><mrow><msub><mi>V</mi><mi>e</mi></msub><msub><mi>A</mi><mi>e</mi></msub><mo>/</mo><msub><mi>A</mi><mi>m</mi></msub><mo>≥</mo><mn>1.6</mn><mspace></mspace><mi>m</mi><mo>/</mo><mi>s</mi></mrow></math></span>) the MCT becomes weakly dependent on fire location when the smoke layer has developed into the one-dimensional flow before reaching the junction. The flame exhibits a longitudinal tilt toward the junction for non-junction fires and lateral guidance into the branch for junction fires. Based on the flame tilting characteristics, an empirical correlation incorporating exhaust volume, tunnel geometry and fire parameters is developed to predict the MCT under strong exhaust. A comparison indicates that centralized smoke exhaust better protects the downstream region, while longitudinal ventilation is more effective in reducing smoke accumulation near the fire source.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"78 ","pages":"Article 107652"},"PeriodicalIF":6.4,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145902616","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–hydraulic optimization of a biomimetic leaf-vein cooling jacket for high-speed motorized spindles 高速电主轴仿生叶脉冷却套的热液优化

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107655

Ye Dai , Cheng Yang , Shiqiang Zhan , Gang Wang , He Hao , Yongjia Huang , Chuang Ming

High-speed motorized spindles operating under high power density are susceptible to excessive temperature rise and non-uniform thermal deformation, which deteriorate machining accuracy, thermal stability, and service life. Achieving uniform and efficient heat removal remains a critical challenge for spindle thermal management, particularly under compact structural constraints. To address this issue, a biomimetic leaf-vein cooling water jacket inspired by natural flow-distribution networks is proposed to enhance coolant uniformity along the stator surface. A sequentially coupled electromagnetics–fluid–structural modeling framework is established to accurately resolve electromagnetic heat generation, conjugate heat transfer, and thermo-structural deformation of the spindle system. Based on the coupled simulation results, a surrogate-assisted multi-objective optimization strategy combining response surface methodology and a genetic algorithm is employed to optimize key geometric and flow parameters of the cooling jacket, aiming to simultaneously reduce stator surface temperature and hydraulic pressure drop. Compared with the baseline configuration, the optimized design achieves a 2.46 % reduction in average stator surface temperature and a 3.21 % decrease in pressure drop without increasing pumping power, while also improving the uniformity of thermal deformation. Furthermore, comparative numerical analysis and indirect experimental validation using a conventional U-shaped cooling jacket confirm the predictive accuracy and engineering applicability of the proposed multiphysics framework. The present study provides a quantitative and reusable optimization route for thermal management design in high-performance motorized spindles.

高速电主轴在高功率密度下工作，容易出现温升过大、热变形不均匀等问题，影响加工精度、热稳定性和使用寿命。实现均匀和有效的散热仍然是主轴热管理的关键挑战，特别是在紧凑的结构约束下。为了解决这一问题，提出了一种受自然流分配网络启发的仿生叶脉冷却水套，以提高冷却剂沿定子表面的均匀性。为了准确解析主轴系统的电磁产热、共轭传热和热结构变形，建立了电磁-流-固序耦合建模框架。基于耦合仿真结果，采用响应面法和遗传算法相结合的代理辅助多目标优化策略，对冷却夹套的关键几何参数和流动参数进行优化，以同时降低定子表面温度和液压降。与基准配置相比，优化设计在不增加泵送功率的情况下，平均定子表面温度降低了2.46%，压降降低了3.21%，同时热变形均匀性也得到了改善。此外，对比数值分析和使用传统u型冷却套的间接实验验证证实了所提出的多物理场框架的预测准确性和工程适用性。本研究为高性能电主轴热管理设计提供了定量和可重复使用的优化途径。

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引用次数: 0

Multi-objective optimization of rural residential buildings in cold regions using BPNN and NSGA-III: A case study of Shangqiu 基于BPNN和NSGA-III的寒区农村居民楼多目标优化——以商丘市为例

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-05 DOI: 10.1016/j.csite.2026.107654

Zhongcheng Duan , Binhao Li , Yidi Zhao , Mingxue Chen

This study proposes a multi-objective optimization framework integrating dynamic simulation, a Backpropagation Neural Network, and the Non-dominated Sorting Genetic Algorithm III to improve energy efficiency, thermal comfort, and affordability of rural houses in cold regions. Using a representative dwelling in Shangqiu, Henan, 21 key variables were identified through sensitivity analysis, and 30,000 samples were generated by Latin Hypercube Sampling. The BPNN achieved high prediction accuracy (R² = 0.967 for EUI_th, 0.988 for PPD). NSGA-III optimization produced 100 Pareto-optimal retrofit schemes, among which three representative solutions—comfort-oriented, balanced, and energy-saving—were selected using TOPSIS. Compared with the baseline, energy consumption decreased by 46.4–67.2 %, and thermal comfort improved by up to 67.5 %, with retrofit costs between ¥36,000–52,000, within the economic capacity of rural households. The findings demonstrate that enhancing envelope insulation and reducing window U-values effectively achieve energy savings and thermal stability, offering quantitative guidance for low-carbon, cost-effective rural housing retrofits.

本研究提出了一种结合动态仿真、反向传播神经网络和非主导排序遗传算法III的多目标优化框架，以提高寒冷地区农村住宅的能效、热舒适性和可负担性。以河南省商丘市某代表性居民点为研究对象，通过敏感性分析确定21个关键变量，并采用拉丁超立方抽样法生成3万个样本。BPNN的预测精度较高（EUIth的R2 = 0.967， PPD的R2 = 0.988）。NSGA-III优化产生了100个帕累托最优改造方案，并利用TOPSIS方法从中选出了舒适、平衡和节能3个具有代表性的方案。与基线相比，能耗下降46.4% ~ 67.2%，热舒适度提高67.5%，改造成本在3.6万元~ 5.2万元之间，在农户经济能力范围内。研究结果表明，加强围护结构保温和降低窗户u值可以有效地实现节能和热稳定性，为低碳、高性价比的农村住房改造提供定量指导。

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引用次数: 0

Optimization study of an R290 electric vehicle thermal management system using a synergistic deep reinforcement learning and genetic algorithm 基于协同深度强化学习和遗传算法的R290电动汽车热管理系统优化研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-03 DOI: 10.1016/j.csite.2026.107649

Congqing Xu , Xianzhen Ruan , Jianghong Wu , Yuhang Chen , Mengliang Yao

High-performance thermal management system (TMS) using environmentally benign refrigerants is critical to the safe, efficient operation of electric vehicles (EVs) and to reducing environmental impact. An indirect TMS based on an R290 vapor-injection (VPI) heat pump was developed in this study, and a simulation platform for the TMS was established based on AMESim software to evaluate system performance. We further propose a hybrid multi-objective optimization (MOO) strategy that couples deep reinforcement learning with non-dominated sorting genetic algorithm II (DRL-NSGA) to determine the optimal operating parameters for system performance and energy efficiency. A theoretical analysis based on hypervolume drift confirms that the algorithm's “warm-start” strategy accelerates convergence and enhances solution diversity. The results demonstrate that, compared to conventional MOO methods, DRL-NSGA produces Pareto fronts with broader coverage and higher solution quality while reducing computational time by more than 60 %. Under the optimized settings, the system's coefficient of performance (COP) was enhanced by up to 7.7 %, with cooling and heating capacities increasing by up to 7.2 % and 5 %, respectively. Furthermore, the time required to reach the target outlet air temperature was significantly reduced by 132 s under cooling and 429 s under heating conditions. The proposed synergistic optimization algorithm offers an effective and efficient solution to MOO in EV thermal management.

使用环保制冷剂的高性能热管理系统（TMS）对于电动汽车（ev）的安全、高效运行和减少对环境的影响至关重要。研制了基于R290蒸汽喷射（VPI）热泵的间接TMS，并基于AMESim软件建立了TMS仿真平台，对系统性能进行了评估。我们进一步提出了一种混合多目标优化（MOO）策略，该策略将深度强化学习与非主导排序遗传算法II （DRL-NSGA）相结合，以确定系统性能和能效的最佳运行参数。基于超体积漂移的理论分析证实了该算法的“热启动”策略加快了收敛速度，提高了解的多样性。结果表明，与传统的MOO方法相比，DRL-NSGA产生的Pareto前沿覆盖范围更广，解质量更高，计算时间减少60%以上。在优化设置下，系统的性能系数（COP）提高了7.7%，制冷量和制热能力分别提高了7.2%和5%。此外，达到目标出口空气温度所需的时间在冷却条件下减少了132秒，在加热条件下减少了429秒。本文提出的协同优化算法为电动汽车热管理中的MOO问题提供了有效的解决方案。

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引用次数: 0

Establishing optimal engine output characteristics by tuning fuel injection parameter utilizing machine learning: operated by mahua biodiesel-diesel blend with antioxidants 利用机器学习调节燃油喷射参数，建立最佳发动机输出特性：由麻花生物柴油-抗氧化剂柴油混合燃料运行

IF 6.8 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-03 DOI: 10.1016/j.csite.2026.107643

Sinnappadass Muniyappan, Sumathy Subramanian, Ravi Krishnaiah

引用次数: 0

Parametric analysis of an energy-efficient atmospheric water harvesting system (AWHs): Optimizing underground coil configurations for economic water production 节能大气集水系统（AWHs）的参数分析：优化地下盘管配置以实现经济采水

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-03 DOI: 10.1016/j.csite.2026.107646

Mohammadreza Hasandust Rostami

Atmospheric water harvesting (AWH) systems have emerged as a critical solution to address global water scarcity, particularly in arid and semi-arid regions where traditional water sources are limited. With over 2 billion people facing water stress worldwide, developing sustainable and energy-efficient water extraction technologies is urgently needed. However, existing AWH methods often suffer from high energy consumption, low yields, or geographical limitations, creating a significant research gap for optimized passive systems. This study investigates an innovative passive AWH system utilizing subsurface geothermal cooling with optimized coil configurations. Four key parameters were analyzed: coil cross-section (rectangular, circular, square, hexagonal), number of coils (8–64), soil type (clay, sandy loam, peat), and coil length (10–40 m). The system employed rectangular stainless-steel coils buried in clay soil at 4.5 m depth, leveraging stable geothermal temperatures for efficient condensation. Results demonstrated that rectangular coils achieved 12.3 % higher water yield than circular designs due to superior surface area and drainage. Clay soil enhanced production by 38.5 % over peat, while increasing coil length from 10 m to 40 m linearly boosted output by 300 %. The system maintained 85.4–85.8 % energy savings compared to vapor compression cycles, with peak nighttime efficiency reaching 87.3 %. Economically, large-scale configurations (64 coils) achieved a payback period of just 1.2 years. These findings validate passive AWH systems as scalable, low-energy solutions for water-scarce regions, with geometric and soil optimizations significantly improving performance.

大气集水（AWH）系统已经成为解决全球水资源短缺的关键解决方案，特别是在传统水资源有限的干旱和半干旱地区。全球有超过20亿人面临用水压力，迫切需要开发可持续和节能的水提取技术。然而，现有的AWH方法往往存在高能耗、低产量或地理限制的问题，这给优化被动系统的研究带来了很大的空白。本研究研究了一种创新的被动AWH系统，该系统利用地下地热冷却和优化的盘管配置。分析了4个关键参数：卷材截面（矩形、圆形、方形、六角形）、卷材数量（8 ~ 64个）、土壤类型（粘土、砂壤土、泥炭）和卷材长度（10 ~ 40 m）。该系统采用矩形不锈钢盘管，埋在4.5米深的粘土中，利用稳定的地热温度进行有效冷凝。结果表明，矩形盘管由于其优越的表面积和排水能力，比圆形盘管的产水量高出12.3%。粘土比泥炭提高了38.5%的产量，而将卷材长度从10米增加到40米，产量直线提高了300%。与蒸汽压缩循环相比，该系统保持了85.4 - 85.8%的节能，峰值夜间效率达到87.3%。在经济上，大规模配置（64个线圈）的投资回收期仅为1.2年。这些发现验证了被动式AWH系统是一种可扩展的、低能耗的解决方案，适用于缺水地区，其几何和土壤优化显著提高了性能。

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引用次数: 0