Case Studies in Thermal Engineering最新文献_第4页

Policy and design recommendations for thermal safety and economic feasibility of lithium-ion battery 便携式设备中锂离子电池模块热失控传播的风冷抑制热管理设计和政策建议

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107534

Yingqi Liu , Lijie Shen , Elshan Mammadov , Xaotoli Megi , Jun Hao

The economic viability of lithium-ion batteries in portable and distributed power applications is increasingly constrained by premature degradation caused by irregular load profiles, mechanical vibration, and variable microclimatic exposure. These stressors elevate operational costs, shorten replacement cycles, and undermine return on investment across mobile energy systems. This study develops a multi-physics–driven degradation and economic assessment framework to quantify how coupled electrochemical, mechanical, and environmental effects translate into accelerated capacity loss and rising lifecycle costs in multi-cell battery modules. Moving beyond conventional thermal-centric analyses, the framework examines stress-induced solid electrolyte interphase (SEI) instability, lithium plating onset, and impedance growth under non-uniform operating conditions representative of hybrid and portable energy platforms. A dual-stage approach is employed: (i) electrochemical–mechanical coupling simulations using a pseudo-2D Newman model integrated with a stress–strain module in COMSOL to capture particle deformation, SEI cracking, and kinetic inefficiencies; and (ii) accelerated aging experiments combining vibration-assisted cycling, dynamic current ripple, and controlled humidity exposure on 18650-based modular packs. Results show that cyclic mechanical strain increases local overpotential by up to 18 %, accelerating lithium plating under low-state-of-charge, high-current regimes and reducing usable capacity retention, while high humidity conditions (>70 % RH) intensify electrolyte decomposition, increasing cell impedance by 22–34 % and raising energy losses per delivered kilowatt-hour. An economic degradation model coupled with a machine-learning prognostic algorithm predicts remaining useful life with an error below 6%, enabling optimization of operating envelopes to minimize replacement frequency and levelized battery cost. The findings demonstrate that mechanically induced electrochemical degradation constitutes a dominant driver of hidden economic loss, often exceeding thermal failure-related costs. The study concludes with economically oriented design and policy recommendations, including vibration-damping system architecture, humidity-adaptive battery management controls, and RUL-based operational limits, offering a scalable pathway to improve cost efficiency, asset longevity, and investment sustainability of lithium-ion battery systems.

锂离子电池在便携式和分布式电源应用中的经济可行性越来越受到不规则负载分布、机械振动和可变小气候暴露引起的过早退化的限制。这些压力因素提高了运营成本，缩短了更换周期，并破坏了整个移动能源系统的投资回报。本研究开发了一个多物理驱动的退化和经济评估框架，以量化电化学、机械和环境耦合效应如何转化为多电池模块中加速的容量损失和不断上升的生命周期成本。除了传统的以热为中心的分析之外，该框架还研究了混合动力和便携式能源平台在非均匀操作条件下应力诱导的固体电解质界面（SEI）不稳定性、锂电镀开始和阻抗增长。采用双阶段方法：(i)使用COMSOL中集成应力应变模块的伪2d Newman模型进行电化学-力学耦合模拟，以捕获颗粒变形、SEI裂纹和动力学低效；（ii）结合振动辅助循环、动态电流纹波和控制湿度暴露在18650基模块化封装上的加速老化实验。结果表明，循环机械应变使局部过电位增加了18%，在低电量、大电流条件下加速了锂电镀，降低了可用容量保留，而高湿条件（> 70% RH）加剧了电解质分解，使电池阻抗增加了22 - 34%，增加了每千瓦时的能量损失。经济退化模型与机器学习预测算法相结合，预测剩余使用寿命的误差低于6%，从而优化操作包，最大限度地减少更换频率，降低电池成本。研究结果表明，机械诱导的电化学降解是潜在经济损失的主要驱动因素，往往超过热失效相关的成本。该研究总结了以经济为导向的设计和政策建议，包括减振系统架构、湿度自适应电池管理控制和基于r的操作限制，为提高锂离子电池系统的成本效率、资产寿命和投资可持续性提供了可扩展的途径。

{"title":"Policy and design recommendations for thermal safety and economic feasibility of lithium-ion battery","authors":"Yingqi Liu , Lijie Shen , Elshan Mammadov , Xaotoli Megi , Jun Hao","doi":"10.1016/j.csite.2025.107534","DOIUrl":"10.1016/j.csite.2025.107534","url":null,"abstract":"<div><div>The economic viability of lithium-ion batteries in portable and distributed power applications is increasingly constrained by premature degradation caused by irregular load profiles, mechanical vibration, and variable microclimatic exposure. These stressors elevate operational costs, shorten replacement cycles, and undermine return on investment across mobile energy systems. This study develops a multi-physics–driven degradation and economic assessment framework to quantify how coupled electrochemical, mechanical, and environmental effects translate into accelerated capacity loss and rising lifecycle costs in multi-cell battery modules. Moving beyond conventional thermal-centric analyses, the framework examines stress-induced solid electrolyte interphase (SEI) instability, lithium plating onset, and impedance growth under non-uniform operating conditions representative of hybrid and portable energy platforms. A dual-stage approach is employed: (i) electrochemical–mechanical coupling simulations using a pseudo-2D Newman model integrated with a stress–strain module in COMSOL to capture particle deformation, SEI cracking, and kinetic inefficiencies; and (ii) accelerated aging experiments combining vibration-assisted cycling, dynamic current ripple, and controlled humidity exposure on 18650-based modular packs. Results show that cyclic mechanical strain increases local overpotential by up to 18 %, accelerating lithium plating under low-state-of-charge, high-current regimes and reducing usable capacity retention, while high humidity conditions (>70 % RH) intensify electrolyte decomposition, increasing cell impedance by 22–34 % and raising energy losses per delivered kilowatt-hour. An economic degradation model coupled with a machine-learning prognostic algorithm predicts remaining useful life with an error below 6%, enabling optimization of operating envelopes to minimize replacement frequency and levelized battery cost. The findings demonstrate that mechanically induced electrochemical degradation constitutes a dominant driver of hidden economic loss, often exceeding thermal failure-related costs. The study concludes with economically oriented design and policy recommendations, including vibration-damping system architecture, humidity-adaptive battery management controls, and RUL-based operational limits, offering a scalable pathway to improve cost efficiency, asset longevity, and investment sustainability of lithium-ion battery systems.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107534"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786025","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

Heat transfer mechanism of EPS concrete with fly ash based on random aggregate model 基于随机骨料模型的粉煤灰EPS混凝土传热机理

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107574

Na Zhang , Chengxi Li , Tianxin Yuan , Liang Li , Yongfeng Cheng

To investigate the heat transfer mechanism of expanded polystyrene (EPS) concrete, this study was designed to experiment the thermal insulation performance of EPS concrete doped with fly ash. A random aggregate model of EPS concrete was also established to verify the accuracy of the model through experiments. The effects of aggregate volume rate, aggregate shape, aggregate distribution mode, interfacial transition zone and porosity on the thermal insulation performance of concrete were investigated. The heat flow and temperature fields of EPS concrete were analyzed to reveal the heat transfer mechanism of EPS concrete. Finally, a second-order heat transfer calculation model for EPS concrete was developed to predict the effective thermal conductivity. The results show that the thermal conductivity decreases with the increase in volume ratio and porosity of EPS particles, and is 0.24 W/(m·K) at the volume ratio of 40 % and porosity of 13.3 %. The lowest thermal conductivity was found in triangular EPS granular concrete and the highest in pentagonal. The reduction in thermal conductivity was most significant when the rotation angle of elliptical EPS particles ψ_a = 0°. As the number of EPS particles and pores increases, the thermal channels narrow, extending the duration of heat flow through the interior of the concrete, which leads to a decrease in thermal conductivity. The established second-order heat transfer model for EPS concrete enables effective prediction of its thermal conductivity. This study integrates experimental, numerical simulation, and theoretical analysis to establish a quantitative relationship between the characteristics of EPS concrete and its thermal performance. The proposed model offers a robust analytical basis for predicting the thermal properties of EPS concrete with fly ash.

为探讨膨胀聚苯乙烯（EPS）混凝土的传热机理，本研究对掺加粉煤灰的EPS混凝土的保温性能进行了试验研究。建立了EPS混凝土随机骨料模型，通过实验验证了模型的准确性。研究了集料体积率、集料形状、集料分布方式、界面过渡区和孔隙率对混凝土保温性能的影响。分析了EPS混凝土的热流场和温度场，揭示了EPS混凝土的传热机理。最后，建立了EPS混凝土的二阶传热计算模型，以预测EPS混凝土的有效导热系数。结果表明：EPS颗粒的导热系数随体积比和孔隙率的增大而减小，当体积比为40%、孔隙率为13.3%时，导热系数为0.24 W/(m·K)；三角形EPS颗粒混凝土的导热系数最低，五边形EPS颗粒混凝土的导热系数最高。当椭圆EPS粒子的旋转角度ψa = 0°时，其导热系数的降低最为显著。随着EPS颗粒和孔隙数量的增加，热通道变窄，延长了热流通过混凝土内部的时间，从而导致导热系数降低。建立的EPS混凝土二阶传热模型能够有效地预测EPS混凝土的导热系数。本研究将实验、数值模拟和理论分析相结合，建立EPS混凝土特性与其热工性能之间的定量关系。该模型为粉煤灰EPS混凝土的热性能预测提供了可靠的分析依据。

{"title":"Heat transfer mechanism of EPS concrete with fly ash based on random aggregate model","authors":"Na Zhang , Chengxi Li , Tianxin Yuan , Liang Li , Yongfeng Cheng","doi":"10.1016/j.csite.2025.107574","DOIUrl":"10.1016/j.csite.2025.107574","url":null,"abstract":"<div><div>To investigate the heat transfer mechanism of expanded polystyrene (EPS) concrete, this study was designed to experiment the thermal insulation performance of EPS concrete doped with fly ash. A random aggregate model of EPS concrete was also established to verify the accuracy of the model through experiments. The effects of aggregate volume rate, aggregate shape, aggregate distribution mode, interfacial transition zone and porosity on the thermal insulation performance of concrete were investigated. The heat flow and temperature fields of EPS concrete were analyzed to reveal the heat transfer mechanism of EPS concrete. Finally, a second-order heat transfer calculation model for EPS concrete was developed to predict the effective thermal conductivity. The results show that the thermal conductivity decreases with the increase in volume ratio and porosity of EPS particles, and is 0.24 W/(m·K) at the volume ratio of 40 % and porosity of 13.3 %. The lowest thermal conductivity was found in triangular EPS granular concrete and the highest in pentagonal. The reduction in thermal conductivity was most significant when the rotation angle of elliptical EPS particles <em>ψ</em><sub><em>a</em></sub> = 0°. As the number of EPS particles and pores increases, the thermal channels narrow, extending the duration of heat flow through the interior of the concrete, which leads to a decrease in thermal conductivity. The established second-order heat transfer model for EPS concrete enables effective prediction of its thermal conductivity. This study integrates experimental, numerical simulation, and theoretical analysis to establish a quantitative relationship between the characteristics of EPS concrete and its thermal performance. The proposed model offers a robust analytical basis for predicting the thermal properties of EPS concrete with fly ash.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107574"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145822875","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

Infrared selective emitter for multiband camouflage with thermal management via femtosecond laser direct writing of grating patterns 利用飞秒激光直接写入光栅图形进行热管理的多波段伪装红外选择性发射器

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107581

Yiyang Shen , Mengdan Qian , Kun Yu , Chunyu Deng , Yufang Liu

The rapid progress of modern detection technologies has placed stringent demands on multiband camouflage systems, rendering single-band designs inadequate for operational use. Metamaterial emitters, due to tunable electromagnetic characteristics, are regarded as highly promising candidates for multiband concealment. Yet, the precise realization of micro/nanostructures remains a persistent fabrication challenge. In this work, a femtosecond laser direct writing (FsLDW) method is employed to produce patterned metamaterial emitters with high accuracy and structural flexibility. Periodic gratings are generated on ultrathin metallic films without thermal diffusion, which ensures uniformity and reproducibility. Using this strategy, a Cu/SiO₂/Cu nanosandwiched selective emitter is fabricated. It achieves dual-band infrared camouflage with high reflectance (R_{3–5 μm} = 0.78 and R_{8–14 μm} = 0.83) and CO₂ laser camouflage via strong absorption at 10.6 μm. Moreover, enhanced emission in the non-atmospheric window (ε_{5–8 μm} = 0.74) facilitates effective thermal management, leading to lower surface temperature compared with low emissivity materials under identical conditions. These findings demonstrate that FsLDW provides a versatile and reliable approach for the development of multiband emitters integrating camouflage and thermal management functionalities.

现代探测技术的快速发展对多波段伪装系统提出了严格的要求，使得单波段设计不足以用于作战使用。由于具有可调谐的电磁特性，超材料发射器被认为是非常有前途的多波段隐藏候选材料。然而，精确实现微/纳米结构仍然是一个持续的制造挑战。本文采用飞秒激光直接写入（FsLDW）方法，制备了具有高精度和结构柔性的图像化超材料发射器。在超薄金属薄膜上产生周期性光栅，无热扩散，保证了均匀性和再现性。利用该方法制备了Cu/SiO2/Cu纳米夹层选择性发射极。实现了高反射率（R3-5 μm = 0.78, R8-14 μm = 0.83）的双频红外伪装和10.6 μm强吸收的CO2激光伪装。此外，在非大气窗口（ε5-8 μm = 0.74）增强的发射有利于有效的热管理，使其表面温度低于相同条件下的低发射率材料。这些发现表明，FsLDW为集成伪装和热管理功能的多波段发射器的开发提供了一种通用和可靠的方法。

{"title":"Infrared selective emitter for multiband camouflage with thermal management via femtosecond laser direct writing of grating patterns","authors":"Yiyang Shen , Mengdan Qian , Kun Yu , Chunyu Deng , Yufang Liu","doi":"10.1016/j.csite.2025.107581","DOIUrl":"10.1016/j.csite.2025.107581","url":null,"abstract":"<div><div>The rapid progress of modern detection technologies has placed stringent demands on multiband camouflage systems, rendering single-band designs inadequate for operational use. Metamaterial emitters, due to tunable electromagnetic characteristics, are regarded as highly promising candidates for multiband concealment. Yet, the precise realization of micro/nanostructures remains a persistent fabrication challenge. In this work, a femtosecond laser direct writing (FsLDW) method is employed to produce patterned metamaterial emitters with high accuracy and structural flexibility. Periodic gratings are generated on ultrathin metallic films without thermal diffusion, which ensures uniformity and reproducibility. Using this strategy, a Cu/SiO<sub>2</sub>/Cu nanosandwiched selective emitter is fabricated. It achieves dual-band infrared camouflage with high reflectance (R<sub>3–5 μm</sub> = 0.78 and R<sub>8–14 μm</sub> = 0.83) and CO<sub>2</sub> laser camouflage via strong absorption at 10.6 μm. Moreover, enhanced emission in the non-atmospheric window (ε<sub>5–8 μm</sub> = 0.74) facilitates effective thermal management, leading to lower surface temperature compared with low emissivity materials under identical conditions. These findings demonstrate that FsLDW provides a versatile and reliable approach for the development of multiband emitters integrating camouflage and thermal management functionalities.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107581"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145822879","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

Solvent-induced microdroplet scattering interface switching in cellulose membranes enables all-season building thermal management 溶剂诱导的微滴散射界面切换在纤维素膜上实现了全季节的建筑热管理

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107576

Wenhui Bao , Yini Tan , Zhen Jia , Guoliang Li , Daxin Liang , Wanke Cheng , Hui Chen

Rising global building energy consumption underscores the urgent need for sustainable materials capable of passive thermal regulation. Regenerated cellulose, a renewable and biodegradable polymer, presents promising potential for energy-efficient optical systems; however, achieving reversible light modulation with precise solvent responsiveness remains a significant challenge. This study introduces an optically switchable regenerated cellulose membrane fabricated through an ionic liquid-based dissolution-regeneration process. The material incorporates dioctyl phthalate (DBP) to dynamically generate and remove microdroplet scattering domains during solvent exchange. The membrane exhibits exceptional optical properties: a transparent state with 95.2 % transmittance in ethanol/DBP and a scattering state achieving 78.5 % visible reflectance in water. Mechanistic investigations reveal that DBP microdroplets (∼5 μm) form due to their hydrophobic characteristics and long carbon chain structure, creating dynamic light-scattering interfaces. Thermal performance evaluation demonstrates a remarkable 14 °C temperature modulation between transparent and scattering states during summer conditions. In winter operation, the transparent mode increases indoor temperature by 13.9 °C with a heating power density of 269.2 W m⁻². By integrating biodegradability, mechanical flexibility, and reversible optical switching capabilities, this membrane offers a groundbreaking solution for energy-adaptive window materials and sustainable building thermal management systems.

全球建筑能耗的不断上升凸显了对能够被动式热调节的可持续材料的迫切需求。再生纤维素是一种可再生和可生物降解的聚合物，在节能光学系统中具有广阔的潜力；然而，实现具有精确溶剂响应性的可逆光调制仍然是一个重大挑战。本研究介绍了一种通过离子液体溶解-再生工艺制备的光学可切换再生纤维素膜。该材料加入邻苯二甲酸二辛酯（DBP），在溶剂交换过程中动态产生和去除微滴散射域。该膜具有优异的光学性能：在乙醇/DBP中具有95.2%的透光率的透明状态，在水中具有78.5%的可见反射率的散射状态。机理研究表明，DBP微滴（~ 5 μm）的形成是由于其疏水特性和长碳链结构，形成动态光散射界面。热性能评估表明，在夏季条件下，透明和散射状态之间存在显著的14°C温度调制。在冬季运行时，透明模式使室内温度升高13.9℃，加热功率密度为269.2 W·m-2。通过整合可生物降解性、机械灵活性和可逆光开关能力，这种膜为能源适应性窗户材料和可持续建筑热管理系统提供了突破性的解决方案。

{"title":"Solvent-induced microdroplet scattering interface switching in cellulose membranes enables all-season building thermal management","authors":"Wenhui Bao , Yini Tan , Zhen Jia , Guoliang Li , Daxin Liang , Wanke Cheng , Hui Chen","doi":"10.1016/j.csite.2025.107576","DOIUrl":"10.1016/j.csite.2025.107576","url":null,"abstract":"<div><div>Rising global building energy consumption underscores the urgent need for sustainable materials capable of passive thermal regulation. Regenerated cellulose, a renewable and biodegradable polymer, presents promising potential for energy-efficient optical systems; however, achieving reversible light modulation with precise solvent responsiveness remains a significant challenge. This study introduces an optically switchable regenerated cellulose membrane fabricated through an ionic liquid-based dissolution-regeneration process. The material incorporates dioctyl phthalate (DBP) to dynamically generate and remove microdroplet scattering domains during solvent exchange. The membrane exhibits exceptional optical properties: a transparent state with 95.2 % transmittance in ethanol/DBP and a scattering state achieving 78.5 % visible reflectance in water. Mechanistic investigations reveal that DBP microdroplets (∼5 μm) form due to their hydrophobic characteristics and long carbon chain structure, creating dynamic light-scattering interfaces. Thermal performance evaluation demonstrates a remarkable 14 °C temperature modulation between transparent and scattering states during summer conditions. In winter operation, the transparent mode increases indoor temperature by 13.9 °C with a heating power density of 269.2 W m<sup>−2</sup>. By integrating biodegradability, mechanical flexibility, and reversible optical switching capabilities, this membrane offers a groundbreaking solution for energy-adaptive window materials and sustainable building thermal management systems.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107576"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145813775","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

Liquid CO2 fire suppression in liquor warehouses: A full-scale experimental study 白酒仓库液体CO2灭火：全尺寸实验研究

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107559

Gang Bai , Wei Wan , Xueming Li , Shuoshuo Wang , Bing Chen , Zaihua Yang

Due to the inadequacy of existing fire suppression technologies in liquor warehouses, this study demonstrates the applicability of liquid CO₂ for extinguishing high-proof liquor fires. Full-scale fire suppression experiments using liquid CO₂ were conducted. Results indicated a 100 % fire extinguishing success rate across all tested scales (4–60 m²). Under a valve opening of 28 % (approximately 450 kg/min), the suppression time was between 17 and 56 s, with amount of liquid CO₂ agent ranges from 0.12 m³ to 0.38 m³(120∼356 kg). Upon extinguishment, the O₂ concentration decreased to 11.4–12.5 %, while the CO₂ concentration reached 17.8–22.6 %. After successful fire suppression, the warehouse environment was fully restored within 10 min through ventilation, significantly accelerating operational recovery. The cooling rate of the liquid CO₂ system increased significantly with fire size expansion, demonstrating advantages in cooling and explosion suppression for large-scale, high-temperature fires. This study confirms the high efficacy and engineering applicability of liquid CO₂ in suppressing liquor warehouse fires, provides theoretical support for fire prevention, and addresses a technical gap in practical implementations within this field.

由于白酒仓库现有灭火技术的不足，本研究证明了液态CO2在扑灭高强度白酒火灾中的适用性。采用液态CO2进行了全尺寸灭火实验。结果表明，所有测试规模（4-60平方米）的灭火成功率为100%。当阀门开度为28%（约450 kg/min）时，抑制时间为17 ~ 56 s，液态CO2剂用量为0.12 m3 ~ 0.38 m3（120 ~ 356 kg）。灭火后，O2浓度降至11.4 ~ 12.5%，CO2浓度达17.8 ~ 22.6%。灭火成功后，通过通风，仓库环境在10分钟内完全恢复，显著加快了作业恢复。随着火灾规模的扩大，液态CO2系统的冷却速率显著增加，在大规模高温火灾的冷却和抑爆方面具有优势。本研究证实了液态CO2对白酒仓库火灾的高效性和工程适用性，为火灾防治提供了理论支持，解决了该领域在实际实施中的技术空白。

{"title":"Liquid CO2 fire suppression in liquor warehouses: A full-scale experimental study","authors":"Gang Bai , Wei Wan , Xueming Li , Shuoshuo Wang , Bing Chen , Zaihua Yang","doi":"10.1016/j.csite.2025.107559","DOIUrl":"10.1016/j.csite.2025.107559","url":null,"abstract":"<div><div>Due to the inadequacy of existing fire suppression technologies in liquor warehouses, this study demonstrates the applicability of liquid CO<sub>2</sub> for extinguishing high-proof liquor fires. Full-scale fire suppression experiments using liquid CO<sub>2</sub> were conducted. Results indicated a 100 % fire extinguishing success rate across all tested scales (4–60 m<sup>2</sup>). Under a valve opening of 28 % (approximately 450 kg/min), the suppression time was between 17 and 56 s, with amount of liquid CO<sub>2</sub> agent ranges from 0.12 m<sup>3</sup> to 0.38 m<sup>3</sup>(120∼356 kg). Upon extinguishment, the O<sub>2</sub> concentration decreased to 11.4–12.5 %, while the CO<sub>2</sub> concentration reached 17.8–22.6 %. After successful fire suppression, the warehouse environment was fully restored within 10 min through ventilation, significantly accelerating operational recovery. The cooling rate of the liquid CO<sub>2</sub> system increased significantly with fire size expansion, demonstrating advantages in cooling and explosion suppression for large-scale, high-temperature fires. This study confirms the high efficacy and engineering applicability of liquid CO<sub>2</sub> in suppressing liquor warehouse fires, provides theoretical support for fire prevention, and addresses a technical gap in practical implementations within this field.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107559"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784670","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

Optimizing building heating demand through solar-air temperature integration: A comprehensive analysis of free heating potential and energy savings 通过太阳能-空气温度集成优化建筑采暖需求：自由采暖潜力和节能的综合分析

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107589

Ali Keçebaş , Hongwei Wu , Mustafa Ertürk , C Ahamed Saleel

This study presents an innovative methodology for estimating building heating demand by incorporating the solar-air temperature concept into heating degree hour (HDH) and free heating degree hour (HDH_free) calculations. Unlike conventional methods that rely solely on ambient temperature, this approach integrates for solar radiation and radiative heat loss, providing a more accurate assessment of heating demand and free heating potential. The results indicate that lowering indoor setpoint temperatures to 18 °C can reduce annual heating demand by 25–40 %, while optimizing the heat transfer coefficient (h_o = 1.8 W/m²K) results in an 82 % increase in HDH_free. This increase is attributed to a reduction in conductive heat losses through the building envelope, allowing solar gains to be retained for a longer period while maximizing passive heating effectiveness. Lower h_o values also minimize radiative and convective heat losses, enabling the absorbed solar energy to remain within the building for an extended duration, ultimately enhancing free heating efficiency. The study also highlights the importance of material properties, with higher solar absorptivity (0.7) leading to a 40 % improvement in energy savings and lower surface emissivity (0.35) contributing to better heat retention. The methodology was validated using data from Muğla, Turkey, demonstrating significant energy cost savings and carbon footprint reductions, especially in electricity-based systems. Future research should focus on refining the solar-air temperature model by incorporating building-specific variables and expanding its application to different climates. This approach offers a valuable contribution to sustainable building design by optimizing passive heating and reducing reliance on mechanical systems.

本研究提出了一种创新的方法，通过将太阳能-空气温度概念纳入加热度小时（HDH）和自由加热度小时（HDHfree）计算中来估计建筑供暖需求。与仅依赖环境温度的传统方法不同，该方法集成了太阳辐射和辐射热损失，提供了更准确的供暖需求和自由供热潜力评估。结果表明，将室内设定温度降低至18°C可使年采暖需求减少25 - 40%，而优化传热系数（ho = 1.8 W/m2K）可使HDHfree增加82%。这一增长归因于通过建筑围护结构的传导热损失的减少，允许太阳能增益保留更长的时间，同时最大限度地提高被动加热效率。较低的ho值也最大限度地减少了辐射和对流热损失，使吸收的太阳能在建筑内停留更长时间，最终提高了自由采暖效率。该研究还强调了材料性能的重要性，较高的太阳吸收率（0.7）可以节省40%的能源，较低的表面发射率（0.35）有助于更好的保温。该方法通过使用土耳其Muğla的数据进行验证，显示出显著的能源成本节约和碳足迹减少，特别是在电力系统中。未来的研究应该把重点放在完善太阳能-空气温度模型上，通过纳入建筑特定的变量，并将其应用于不同的气候。这种方法通过优化被动式供暖和减少对机械系统的依赖，为可持续建筑设计提供了宝贵的贡献。

{"title":"Optimizing building heating demand through solar-air temperature integration: A comprehensive analysis of free heating potential and energy savings","authors":"Ali Keçebaş , Hongwei Wu , Mustafa Ertürk , C Ahamed Saleel","doi":"10.1016/j.csite.2025.107589","DOIUrl":"10.1016/j.csite.2025.107589","url":null,"abstract":"<div><div>This study presents an innovative methodology for estimating building heating demand by incorporating the solar-air temperature concept into heating degree hour (HDH) and free heating degree hour (HDH<sub>free</sub>) calculations. Unlike conventional methods that rely solely on ambient temperature, this approach integrates for solar radiation and radiative heat loss, providing a more accurate assessment of heating demand and free heating potential. The results indicate that lowering indoor setpoint temperatures to 18 °C can reduce annual heating demand by 25–40 %, while optimizing the heat transfer coefficient (h<sub>o</sub> = 1.8 W/m<sup>2</sup>K) results in an 82 % increase in HDH<sub>free</sub>. This increase is attributed to a reduction in conductive heat losses through the building envelope, allowing solar gains to be retained for a longer period while maximizing passive heating effectiveness. Lower h<sub>o</sub> values also minimize radiative and convective heat losses, enabling the absorbed solar energy to remain within the building for an extended duration, ultimately enhancing free heating efficiency. The study also highlights the importance of material properties, with higher solar absorptivity (0.7) leading to a 40 % improvement in energy savings and lower surface emissivity (0.35) contributing to better heat retention. The methodology was validated using data from Muğla, Turkey, demonstrating significant energy cost savings and carbon footprint reductions, especially in electricity-based systems. Future research should focus on refining the solar-air temperature model by incorporating building-specific variables and expanding its application to different climates. This approach offers a valuable contribution to sustainable building design by optimizing passive heating and reducing reliance on mechanical systems.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107589"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145822873","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 hazard risk and decomposition mechanism identification of nitrobenzene with mononitrophenol impurities: Combined kinetic and products analysis 含单硝基酚杂质的硝基苯的热危害风险及分解机理鉴定：动力学与产物分析相结合

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107586

Juan Cheng , Chengyang Cao , Chong Xia , Guangyao Zheng , Chuan Zhang , Hongyun Hu

Nitrobenzene (NB), as a critical chemical intermediate with annual consumption exceeding one million tons, is widely used in the chemical manufacturing industry. However, its poor thermal stability when contaminated with impurities has caused multiple fire and explosion incidents. This study aims to investigate the effects of two typical phenols, p-nitrophenol (PNP) and o-nitrophenol (ONP), on the thermal behaviors of NB, and elucidate the impact mechanism. Experimental results indicate that the addition of 10 % wt. PNP or ONP significantly reduces the main decomposition peak temperature of NB, initiating low-temperature exothermic reactions. Kinetic analysis reveals that while these additives increase the activation energy, the dramatic rise in pre-exponential factor indicates fundamental changes in the decomposition pathway. Specifically, NB-ONP exhibits the highest apparent activation energy due to intramolecular hydrogen bonding. Cleavage of these hydrogen bonds generates highly reactive phenoxy radicals that drive an efficient nitro-reduction pathway, leading to the most pronounced thermal hazard. Pure NB decomposition follows a second-order reaction model (F2), while mixtures with PNP or ONP conform to nucleation-growth (A3) and first-order (F1) models, respectively. Product analysis confirms that phenolic impurities reconstruct the reaction network through more complex pathways. Consequently, the thermal hazard risk follows NB-ONP > NB-PNP > NB. These findings provide crucial guidance for NB production: priority should be given to controlling high-risk ONP impurity generation by optimizing nitration process conditions to suppress relevant side reactions. The study clarifies the microscopic mechanism and provides important theoretical basis for targeted impurity management and safe NB production.

硝基苯（NB）作为年消耗量超过百万吨的重要化工中间体，广泛应用于化工制造行业。但由于其在被杂质污染时热稳定性差，已造成多起火灾和爆炸事故。本研究旨在探讨对硝基苯酚（PNP）和邻硝基苯酚（ONP）两种典型酚类对NB热行为的影响，并阐明其影响机理。实验结果表明，添加10% wt. PNP或ONP可显著降低NB的主分解峰温度，引发低温放热反应。动力学分析表明，虽然这些添加剂增加了活化能，但指前因子的急剧上升表明分解途径发生了根本性的变化。由于分子内氢键的作用，NB-ONP表现出最高的表观活化能。这些氢键的断裂产生高活性的苯氧自由基，驱动有效的氮还原途径，导致最明显的热危害。纯NB分解遵循二级反应模型（F2），而与PNP或ONP混合则分别遵循成核生长模型（A3）和一级反应模型（F1）。产物分析证实，酚类杂质通过更复杂的途径重建反应网络。因此，热危害风险遵循NB- onp >； NB- pnp >； NB。这些发现为NB生产提供了重要的指导：应优先考虑通过优化硝化工艺条件来抑制相关副反应来控制高风险ONP杂质的产生。该研究阐明了微观机理，为有针对性的杂质治理和铌安全生产提供了重要的理论依据。

{"title":"Thermal hazard risk and decomposition mechanism identification of nitrobenzene with mononitrophenol impurities: Combined kinetic and products analysis","authors":"Juan Cheng , Chengyang Cao , Chong Xia , Guangyao Zheng , Chuan Zhang , Hongyun Hu","doi":"10.1016/j.csite.2025.107586","DOIUrl":"10.1016/j.csite.2025.107586","url":null,"abstract":"<div><div>Nitrobenzene (NB), as a critical chemical intermediate with annual consumption exceeding one million tons, is widely used in the chemical manufacturing industry. However, its poor thermal stability when contaminated with impurities has caused multiple fire and explosion incidents. This study aims to investigate the effects of two typical phenols, p-nitrophenol (PNP) and o-nitrophenol (ONP), on the thermal behaviors of NB, and elucidate the impact mechanism. Experimental results indicate that the addition of 10 % wt. PNP or ONP significantly reduces the main decomposition peak temperature of NB, initiating low-temperature exothermic reactions. Kinetic analysis reveals that while these additives increase the activation energy, the dramatic rise in pre-exponential factor indicates fundamental changes in the decomposition pathway. Specifically, NB-ONP exhibits the highest apparent activation energy due to intramolecular hydrogen bonding. Cleavage of these hydrogen bonds generates highly reactive phenoxy radicals that drive an efficient nitro-reduction pathway, leading to the most pronounced thermal hazard. Pure NB decomposition follows a second-order reaction model (F2), while mixtures with PNP or ONP conform to nucleation-growth (A3) and first-order (F1) models, respectively. Product analysis confirms that phenolic impurities reconstruct the reaction network through more complex pathways. Consequently, the thermal hazard risk follows NB-ONP > NB-PNP > NB. These findings provide crucial guidance for NB production: priority should be given to controlling high-risk ONP impurity generation by optimizing nitration process conditions to suppress relevant side reactions. The study clarifies the microscopic mechanism and provides important theoretical basis for targeted impurity management and safe NB production.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107586"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145823731","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

Characterization and predictive modeling of intake blockage in rotating detonation combustor 旋转爆震燃烧室进气堵塞特性及预测建模

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107608

Jinhui Kang , Feilong Song , Xin Chen , Yun Wu , Dengcheng Zhang , Xiaopeng Sun , Jiaojiao Wang , Zhao Yang

<div><div>The intake blockage of the rotating detonation combustor (RDC) results from the interaction between the high-pressure detonation wave and the intake air of the combustor, which affects the working stability and performance parameters of the combustor. Based on this research background, a series of experiments were conducted under different flow rates and nozzle structures. A method for calculating the intake blockage based on the throat pressure of the combustor was proposed. The intake characteristics of the combustor under three intake states were analyzed, and the discrimination criteria for different intake states of the combustor were proposed. The proportion of intake blockage of the combustor was fitted by the dimensionless discrimination parameters. After correction by the fitting function, the proportion of intake blockage of the combustor was predicted with high accuracy (<span><math><mrow><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0.98</mn></mrow></math></span>). The propagation mode and stability of the detonation wave under different working conditions were analyzed, and the relationship between the proportion of intake blockage and the propagation characteristics of the detonation wave was explored. It was found that when the proportion of intake blockage was zero, the detonation wave propagated in a single wave mode. With the decrease in throat flow capacity and the increase in intake blockage ratio, unstable modes begin to occur, accompanied by reduced stability in detonation wave propagation. When the throat was in fully subsonic flow, the intake filling speed of the combustor decreased significantly, and the longitudinal pulsed detonation mode were easily induced. The relationship between the intensity of the pressure feedback and the upstream chamber pressure rise ratio and the intake blockage was analyzed, and the relevant relationships were fitted for the construction of the prediction model. The research results show that with the increase of the proportion of intake blockage, the intensity of the pressure feedback and the upstream chamber pressure rise ratio both increase. The intensity of the pressure feedback is affected by many factors and is simultaneously influenced by the detonation wave intensity and the throat flow state, so its fitting accuracy is relatively low (<span><math><mrow><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0.855</mn></mrow></math></span>). However, the upstream chamber pressure rise is mainly induced by the intake blockage, so a higher fitting accuracy can be achieved (<span><math><mrow><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0.98</mn></mrow></math></span>). However, due to the additional aerodynamic losses caused by the feedback shock wave, the predicted results are lower than the experimental measurement values. In summary, this research work clarifies the relationship between the intake blockage of the rotating detonation combustor and the working characteristics of the

旋转爆震燃烧室进气堵塞是高压爆震波与燃烧室进气相互作用的结果，影响了燃烧室的工作稳定性和性能参数。在此研究背景下，进行了不同流量和喷嘴结构下的一系列实验。提出了一种基于燃烧室喉部压力计算进气堵塞的方法。分析了三种进气状态下燃烧室的进气特性，提出了燃烧室不同进气状态的判别准则。采用无因次判别参数拟合燃烧室进气堵塞比例。经拟合函数校正后，预测燃烧室进气堵塞比例精度较高（R2=0.98）。分析了不同工况下爆震波的传播方式和稳定性，探讨了进气堵塞比例与爆震波传播特性的关系。研究发现，当进气堵塞比例为零时，爆震波以单波模式传播。随着喉道流量的减小和进气堵塞比的增大，开始出现不稳定模态，爆震波传播稳定性降低。当喉道处于全亚音速流动状态时，燃烧室进气填充速度明显降低，容易诱发纵向脉冲爆轰模式。分析了压力反馈强度与上游室压升比和进气堵塞之间的关系，并拟合了相关关系，构建了预测模型。研究结果表明，随着进气堵塞比例的增加，压力反馈强度和上游室压升比均增大。压力反馈强度受多种因素影响，同时受爆震波强度和喉道流动状态的影响，因此其拟合精度较低（R2=0.855）。而上游腔室压力上升主要由进气堵塞引起，因此可以获得较高的拟合精度（R2=0.98）。然而，由于反馈激波带来的额外气动损失，预测结果低于实验测量值。综上所述，本研究工作明确了旋转爆震燃烧室进气堵塞与燃烧室工作特性之间的关系，对于充分了解旋转爆震燃烧室的工作原理，指导燃烧室的结构设计具有重要意义。

{"title":"Characterization and predictive modeling of intake blockage in rotating detonation combustor","authors":"Jinhui Kang , Feilong Song , Xin Chen , Yun Wu , Dengcheng Zhang , Xiaopeng Sun , Jiaojiao Wang , Zhao Yang","doi":"10.1016/j.csite.2025.107608","DOIUrl":"10.1016/j.csite.2025.107608","url":null,"abstract":"<div><div>The intake blockage of the rotating detonation combustor (RDC) results from the interaction between the high-pressure detonation wave and the intake air of the combustor, which affects the working stability and performance parameters of the combustor. Based on this research background, a series of experiments were conducted under different flow rates and nozzle structures. A method for calculating the intake blockage based on the throat pressure of the combustor was proposed. The intake characteristics of the combustor under three intake states were analyzed, and the discrimination criteria for different intake states of the combustor were proposed. The proportion of intake blockage of the combustor was fitted by the dimensionless discrimination parameters. After correction by the fitting function, the proportion of intake blockage of the combustor was predicted with high accuracy (<span><math><mrow><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0.98</mn></mrow></math></span>). The propagation mode and stability of the detonation wave under different working conditions were analyzed, and the relationship between the proportion of intake blockage and the propagation characteristics of the detonation wave was explored. It was found that when the proportion of intake blockage was zero, the detonation wave propagated in a single wave mode. With the decrease in throat flow capacity and the increase in intake blockage ratio, unstable modes begin to occur, accompanied by reduced stability in detonation wave propagation. When the throat was in fully subsonic flow, the intake filling speed of the combustor decreased significantly, and the longitudinal pulsed detonation mode were easily induced. The relationship between the intensity of the pressure feedback and the upstream chamber pressure rise ratio and the intake blockage was analyzed, and the relevant relationships were fitted for the construction of the prediction model. The research results show that with the increase of the proportion of intake blockage, the intensity of the pressure feedback and the upstream chamber pressure rise ratio both increase. The intensity of the pressure feedback is affected by many factors and is simultaneously influenced by the detonation wave intensity and the throat flow state, so its fitting accuracy is relatively low (<span><math><mrow><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0.855</mn></mrow></math></span>). However, the upstream chamber pressure rise is mainly induced by the intake blockage, so a higher fitting accuracy can be achieved (<span><math><mrow><msup><mi>R</mi><mn>2</mn></msup><mo>=</mo><mn>0.98</mn></mrow></math></span>). However, due to the additional aerodynamic losses caused by the feedback shock wave, the predicted results are lower than the experimental measurement values. In summary, this research work clarifies the relationship between the intake blockage of the rotating detonation combustor and the working characteristics of the ","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107608"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145844937","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

Modulation of phase change heat transfer performance in triply periodic minimal surface based porous structures 三周期最小表面基多孔结构相变传热性能的调制

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107558

Zhan Wang , Zekuan Liu , Jiang Qin

Solid-liquid phase change processes are recognized as highly potential solutions for thermal energy storage, thermal management and temperature control for significant latent heat capacity and precise temperature regulation capabilities. Nonetheless, the poor thermal conductivity acts as a bottleneck to advancing heat transfer efficiency. Herein, triply periodic minimal surface (TPMS) were employed as thermal conductivity enhancers, and numerical investigates were conducted for the composite phase change materials (CPCMs) with uniform and gradient TPMS structures. Findings suggest that the W-type structure demonstrates significant advantages in liquid fraction distribution, complete melting time, and thermal wall temperature regulation for their high specific surface area and smooth heat transfer pathways. CPCMs with porosity increasing from bottom to top significantly shorten the phase change time but worsen the uniformity of wall temperature distribution. Conversely, CPCMs characterized by a reduction in porosity along the vertical direction from the base to the top exhibit higher thermal resistance and slower phase change rates, while gradient pore density exerts a weaker influence compared to gradient porosity. Furthermore, a dual-gradient porosity structure is further proposed, reducing the complete melting time by 3.69 % compared with the uniform case. More importantly, it markedly improves hot-wall thermal uniformity, lowering temperature inhomogeneity by 47.74 %. This demonstrates that the dual-gradient design can simultaneously accelerate melting and suppress thermal non-uniformity, highlighting its comprehensive performance advantages.

固液相变过程被认为是热能储存、热管理和温度控制的极具潜力的解决方案，具有显著的潜热容量和精确的温度调节能力。然而，导热性差是提高传热效率的瓶颈。本文采用三周期最小表面（TPMS）作为导热增强剂，对具有均匀梯度TPMS结构的复合相变材料（CPCMs）进行了数值研究。研究结果表明，w型结构具有较高的比表面积和光滑的传热路径，在液相分数分布、完全熔化时间和热壁温度调节方面具有显著优势。孔隙率自下而上递增的cpcm相变时间明显缩短，但壁温分布的均匀性变差。相反，从底部到顶部沿垂直方向孔隙度降低的cpcm表现出更高的热阻和更慢的相变速率，而梯度孔隙密度对梯度孔隙度的影响较弱。进一步提出了双梯度孔隙结构，与均匀情况相比，完全熔化时间缩短了3.69%。更重要的是，它显著改善了热壁的热均匀性，温度不均匀性降低了47.74%。这说明双梯度设计可以同时加速熔化和抑制热不均匀性，凸显其综合性能优势。

{"title":"Modulation of phase change heat transfer performance in triply periodic minimal surface based porous structures","authors":"Zhan Wang , Zekuan Liu , Jiang Qin","doi":"10.1016/j.csite.2025.107558","DOIUrl":"10.1016/j.csite.2025.107558","url":null,"abstract":"<div><div>Solid-liquid phase change processes are recognized as highly potential solutions for thermal energy storage, thermal management and temperature control for significant latent heat capacity and precise temperature regulation capabilities. Nonetheless, the poor thermal conductivity acts as a bottleneck to advancing heat transfer efficiency. Herein, triply periodic minimal surface (TPMS) were employed as thermal conductivity enhancers, and numerical investigates were conducted for the composite phase change materials (CPCMs) with uniform and gradient TPMS structures. Findings suggest that the W-type structure demonstrates significant advantages in liquid fraction distribution, complete melting time, and thermal wall temperature regulation for their high specific surface area and smooth heat transfer pathways. CPCMs with porosity increasing from bottom to top significantly shorten the phase change time but worsen the uniformity of wall temperature distribution. Conversely, CPCMs characterized by a reduction in porosity along the vertical direction from the base to the top exhibit higher thermal resistance and slower phase change rates, while gradient pore density exerts a weaker influence compared to gradient porosity. Furthermore, a dual-gradient porosity structure is further proposed, reducing the complete melting time by 3.69 % compared with the uniform case. More importantly, it markedly improves hot-wall thermal uniformity, lowering temperature inhomogeneity by 47.74 %. This demonstrates that the dual-gradient design can simultaneously accelerate melting and suppress thermal non-uniformity, highlighting its comprehensive performance advantages.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107558"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784659","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

Investigation of the mechanical characteristics of limestone after high-temperature treatment and the T-M coupling constitutive model based on statistical damage 石灰石高温处理力学特性研究及基于统计损伤的T-M耦合本构模型

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering

Pub Date : 2026-01-01 DOI: 10.1016/j.csite.2025.107557

Xingchen Liu , Feng Huang , Yang Hu , Aichen Zheng , Dong Yang

Thermal damage induces changes in the mechanical properties of rock, making it crucial to clarify the thermal damage characteristics of rock and describe the thermo-mechanical coupling behavior of thermally damaged rock. Limestone samples were heat-treated at 100–600 °C, followed by triaxial compression tests on the thermally damaged samples. Scanning electron microscopy (SEM) was used to observe their microscopic thermal damage characteristics. Based on the micro-element concept, a pore compaction coefficient was defined. Integrating the Hooke-Brown strength criterion and the micro-element cumulative damage parameter, a Weibull distribution-based thermo-mechanical coupling statistical damage constitutive model for limestone was established. The coefficient of determination (R²) between the model-calculated results and the experimental stress-strain curves reached 0.98. Microscopically, high-temperature-induced rock damage is characterized by crack propagation and pore erosion. As temperature increases, the elastic modulus decreases nonlinearly, while the peak compressive strength first increases and then decreases. Under compressive loading, the total pore closure strain increases with the heat-treatment temperature. The proposed constitutive model effectively captures the nonlinear deformation characteristics during the initial compaction stage.

热损伤会引起岩石力学性质的变化，因此阐明岩石热损伤特征和描述热损伤岩石的热-力耦合行为至关重要。对石灰石试样进行100-600℃的热处理，然后对热损伤试样进行三轴压缩试验。利用扫描电子显微镜（SEM）观察了其显微热损伤特征。基于微元素概念，定义了孔隙压实系数。结合Hooke-Brown强度准则和微元累积损伤参数，建立了基于Weibull分布的石灰岩热-力耦合统计损伤本构模型。模型计算结果与试验应力-应变曲线的决定系数R2达到0.98。微观上，岩石高温损伤表现为裂纹扩展和孔隙侵蚀。随着温度的升高，弹性模量呈非线性减小，峰值抗压强度先增大后减小。压缩载荷作用下，总闭孔应变随热处理温度的升高而增大。提出的本构模型有效地捕捉了初始压实阶段的非线性变形特征。

{"title":"Investigation of the mechanical characteristics of limestone after high-temperature treatment and the T-M coupling constitutive model based on statistical damage","authors":"Xingchen Liu , Feng Huang , Yang Hu , Aichen Zheng , Dong Yang","doi":"10.1016/j.csite.2025.107557","DOIUrl":"10.1016/j.csite.2025.107557","url":null,"abstract":"<div><div>Thermal damage induces changes in the mechanical properties of rock, making it crucial to clarify the thermal damage characteristics of rock and describe the thermo-mechanical coupling behavior of thermally damaged rock. Limestone samples were heat-treated at 100–600 °C, followed by triaxial compression tests on the thermally damaged samples. Scanning electron microscopy (SEM) was used to observe their microscopic thermal damage characteristics. Based on the micro-element concept, a pore compaction coefficient was defined. Integrating the Hooke-Brown strength criterion and the micro-element cumulative damage parameter, a Weibull distribution-based thermo-mechanical coupling statistical damage constitutive model for limestone was established. The coefficient of determination (R<sup>2</sup>) between the model-calculated results and the experimental stress-strain curves reached 0.98. Microscopically, high-temperature-induced rock damage is characterized by crack propagation and pore erosion. As temperature increases, the elastic modulus decreases nonlinearly, while the peak compressive strength first increases and then decreases. Under compressive loading, the total pore closure strain increases with the heat-treatment temperature. The proposed constitutive model effectively captures the nonlinear deformation characteristics during the initial compaction stage.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"77 ","pages":"Article 107557"},"PeriodicalIF":6.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784660","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