Case Studies in Thermal Engineering最新文献

CFD study on combustion and emissions characteristics of methane-hydrogen co-firing in an EV burner 电动汽车燃烧器甲烷-氢共燃燃烧及排放特性CFD研究

IF 6.8 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-28 DOI: 10.1016/j.csite.2025.106596

Sanghyeon Lee, Jaebin Lee, Byeongmin Ahn, Dowon Kang, Jeongjae Hwang, Yeseul Park, Minsung Choi

{"title":"CFD study on combustion and emissions characteristics of methane-hydrogen co-firing in an EV burner","authors":"Sanghyeon Lee, Jaebin Lee, Byeongmin Ahn, Dowon Kang, Jeongjae Hwang, Yeseul Park, Minsung Choi","doi":"10.1016/j.csite.2025.106596","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106596","url":null,"abstract":"Considerable efforts are being made worldwide to convert carbon-free fuels from gas turbines in the power generation sector while focusing on reducing greenhouse gases. In this study, CFD analysis was conducted to investigate the effects of methane–hydrogen co-firing on the combustion characteristics of a gas turbine combustor for power. This study aims to explore the combustion and emissions characteristics under various operating conditions, such as different co-firing and equivalence ratios. As the hydrogen co-firing ratio increased from 0% to 60%, the flame became increasingly attached to the burner, with the OH reaction zone shifting upstream by up to 80 mm, suggesting a higher risk of flashback owing to hydrogen. The emission characteristics showed an increase in NO<ce:inf loc=\"post\">x</ce:inf>, reaching approximately 140 ppm at an equivalence ratio of 0.7, as observed in both the experiments and CFD. Changes in the operating conditions based on the equivalence ratio revealed the development of an inner recirculation zone within the burner, which led to changes in the flame structure. The maximum temperature in the flame region increased to approximately 2200 K. These numerical results can serve as a reference for providing operational guidelines and assessing the feasibility of hydrogen co-firing in industrial gas turbines.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"9 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144503911","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

Artificial Neural Network based Enhanced Thermal Energy Storage System for Renewable Energy using Nano-Particles 基于人工神经网络的纳米可再生能源增强型储能系统

IF 6.8 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-28 DOI: 10.1016/j.csite.2025.106586

Saima Zainab, Meraj Ali Khan, Sharmeen, Hassan Waqas

{"title":"Artificial Neural Network based Enhanced Thermal Energy Storage System for Renewable Energy using Nano-Particles","authors":"Saima Zainab, Meraj Ali Khan, Sharmeen, Hassan Waqas","doi":"10.1016/j.csite.2025.106586","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106586","url":null,"abstract":"Thermal energy storage (TES) has appeared to be a viable answer to the world’s energy concerns. Combining Latent Heat Storage Systems (LHSS) with renewable (solar) energy sources has improved the sustainability and efficiency of energy systems worldwide. Phase Change Material (PCM) stores thermal energy during phase transition, making them ideal for thermal control applications. This study offers a comprehensive analytical framework for improving TES systems using advanced materials and innovative configurations, thereby enhancing energy storage efficiency due to the rotational effects of fins. We have integrated V-shaped fins and incorporated nanoparticles <ce:math altimg=\"si1.svg\"></ce:math> and <ce:math altimg=\"si2.svg\"></ce:math> to PCM to improve the thermal conductivity and storage capacity of LHSS. Enthalpy-porosity model is employed to represent the melting process of PCM using ANSYS Fluent. The consequences of distinct rotational speeds (0.1 rpm, 0.2 rpm and 0.3 rpm) of the V-shaped fins on the thermal performance of PCM are investigated. The temperature distribution with enhanced PCM is more even and effective. Improved thermal performance is achieved by amalgamating rotating V-shaped fins with PCM augmented with nanoparticles. Results demonstrate that increasing rotational speed leads to improved energy storage, up to a 5.43% increase at 0.3 rpm along with a reduction in the Nusselt number. This performance enhancement is attributed to improved thermal mixing and more effective utilization of the phase change material, highlighting the potential of rotational fins as a thermal optimization strategy. After obtaining the results from the solver, TES performance is predicted using artificial neural networks (ANNs), which offer a powerful analytical tool for comprehending the intricate relationships within the system.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"27 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144503910","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

Mechanisms of Long-Term Ultraviolet Radiation on the Low-Temperature Oxidation Characteristics of Coal with Varying Degrees of Metamorphism 长期紫外线辐射对不同变质程度煤低温氧化特性的影响机理

IF 6.8 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-28 DOI: 10.1016/j.csite.2025.106599

Xun Zhang, Huimin Liang, Bing Lu, Ling Qiao, Ge Huang, Fengwei Dai, Chen Yu, Chuang Li

{"title":"Mechanisms of Long-Term Ultraviolet Radiation on the Low-Temperature Oxidation Characteristics of Coal with Varying Degrees of Metamorphism","authors":"Xun Zhang, Huimin Liang, Bing Lu, Ling Qiao, Ge Huang, Fengwei Dai, Chen Yu, Chuang Li","doi":"10.1016/j.csite.2025.106599","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106599","url":null,"abstract":"To investigate the impact of prolonged ultraviolet (UV) radiation on the low-temperature oxidation characteristics of coals with varying degrees of metamorphism, this study employed temperature-programmed oxidation and in-situ Fourier-transform infrared (In-situ FTIR) spectroscopy. The research focused on brown coal, long-flame coal, and coking coal, examining both untreated samples and those subjected to UV radiation for 3, 6, 9, and 12 months. The results demonstrated that long-term UV radiation consistently promotes low-temperature oxidation in coals, with this effect peaking at 6 months. At this peak, compared to untreated coals, brown coal exhibited increases in CO and CO<ce:inf loc=\"post\">2</ce:inf> yields of 2.06 and 2.25 times, respectively; long-flame coal showed increases of 1.93 and 2.06 times, respectively; and coking coal demonstrated increases of 1.85 and 2.00 times, respectively. Further analysis revealed that the impact of prolonged UV radiation on coal’s low-temperature oxidation mechanism varies across different coal types and oxidation stages. This variation is reflected in coal-specific and stage-dependent changes in key active functional groups and the groups contributing most to structural changes when comparing untreated and UV-irradiated coals. These findings provide a theoretical foundation for evaluating and mitigating the self-ignition risks of coals subjected to long-term UV radiation exposure.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"13 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144503909","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 comfort model for classrooms using occupant-centered approach 以乘员为中心的教室热舒适模型

IF 6.8 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-27 DOI: 10.1016/j.csite.2025.106589

Huda Riaz, Sabahat Arif, Sumra Yousuf, Muhammad Nasir Bashir, Muhammad Mahmood Ali, Irfan Anjum Badruddin

引用次数: 0

Numerical study of parametric effects on heat transfer deterioration of supercritical CO2/DME mixture flowing in a horizontal tube 超临界CO2/二甲醚混合物水平管内流动传热恶化的参数影响数值研究

IF 6.8 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-27 DOI: 10.1016/j.csite.2025.106567

Xiaojuan Niu, Ziyang Yin, Wenpeng Hong

{"title":"Numerical study of parametric effects on heat transfer deterioration of supercritical CO2/DME mixture flowing in a horizontal tube","authors":"Xiaojuan Niu, Ziyang Yin, Wenpeng Hong","doi":"10.1016/j.csite.2025.106567","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106567","url":null,"abstract":"Compared to using pure CO<ce:inf loc=\"post\">2</ce:inf> as a working fluid, mixing CO<ce:inf loc=\"post\">2</ce:inf> with dimethyl ether (DME) in specific ratios can enhance heat transfer efficiency and reduce system operating pressure. However, the issue of heat transfer deterioration (HTD) in supercritical CO<ce:inf loc=\"post\">2</ce:inf>/DME mixtures has received limited attention. This study conducts a numerical analysis of the heat transfer characteristics of these mixtures in horizontal tubes. We conducted a systematic study for the first time on how various operating parameters influence the HTD mechanism and establish multiscale correlations between mixture thermophysical nonlinearities and thermal transport instabilities.The findings offer valuable insights for the safe operation of next-generation energy systems. Results show that DME addition delays HTD, while increasing system pressure and mass flux helps mitigate its severity. Moreover, gravitational acceleration introduces asymmetry in the local heat transfer coefficient (HTC) distribution. Under normal gravity conditions (gy = -9.8 m/s<ce:sup loc=\"post\">2</ce:sup>), HTC suppression is observed compared to the zero-gravity condition (gy = 0 m/s<ce:sup loc=\"post\">2</ce:sup>).","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"2 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144503927","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

Study of flow and heat transfer characteristics of tandem cold plates for data center cooling 数据中心冷却用串联冷板的流动和传热特性研究

IF 6.8 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-27 DOI: 10.1016/j.csite.2025.106590

Jinbo Li, Xue Luo, Man Wang, Chaowei Chen, Chen Yang, Zheng Zhang, Gongming Xin

{"title":"Study of flow and heat transfer characteristics of tandem cold plates for data center cooling","authors":"Jinbo Li, Xue Luo, Man Wang, Chaowei Chen, Chen Yang, Zheng Zhang, Gongming Xin","doi":"10.1016/j.csite.2025.106590","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106590","url":null,"abstract":"As data center chip power densities increase, liquid-cooling cold plates have gained widespread attention for their superior thermal management performance. This study systematically analyzes the thermal-hydraulic performance of tandem cold plates with different combination modes through numerical simulations and experimental validation. Results indicate that LCP2 (cold plate with narrow channel width) reduces thermal resistance (<ce:italic>R</ce:italic><ce:inf loc=\"post\"><ce:italic>t</ce:italic></ce:inf>) by 29 % compared to LCP1 (cold plate with wide channel width) but increases pressure drop (<ce:italic>ΔP</ce:italic>) by 141 %. The LCP1+2 tandem mode combining a primary cold plate LCP1 and a secondary cold plate LCP2 achieves optimal thermal performance, which has a 3.49 °C reduction in the maximum chip temperature (<ce:italic>T</ce:italic><ce:inf loc=\"post\"><ce:italic>max</ce:italic></ce:inf>), 15 % lower total thermal resistance (<ce:italic>R</ce:italic><ce:inf loc=\"post\"><ce:italic>t, total</ce:italic></ce:inf>), and twofold improvement in thermal performance index (<ce:italic>TPI</ce:italic>) compared to LCP1+1 mode (two LCP1 tandem). In addition, as inlet temperature or load rate rises, increasing the flow rate can effectively reduce the temperature difference between two CPUs and improve system temperature uniformity. The deviation between the simulated data and the experimental data is within 2.32 %, confirming the accuracy of the model. This work offers valuable insights for improving the cooling efficiency and thermal uniformity of liquid cooling systems, ensuring safe and reliable operation in high-performance data center environments.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"93 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144503930","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

Integrated Computational and Experimental Evaluation of Thermal Optimization in Energy Pile Groups in Soft Clay 软土中能源桩群热优化综合计算与实验评价

IF 6.8 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-27 DOI: 10.1016/j.csite.2025.106571

Thiti Chanchayanon, Susit Chaiprakaikeow, Apiniti Jotisankasa, Shinya Inazumi

引用次数: 0

Multi-field Coupling Mechanism and Optimization of Heat Transfer in Deep Carbonate Geothermal Reservoirs Based on Acid Fracturing Modification 基于酸压改造的深层碳酸盐岩地热储层多场耦合机理及换热优化

IF 6.8 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-26 DOI: 10.1016/j.csite.2025.106591

Xinghui Wu, Peng Li, Shengjun Miao, Meifeng Cai, Yan Liu, Min Wang, Wensai Xiong

{"title":"Multi-field Coupling Mechanism and Optimization of Heat Transfer in Deep Carbonate Geothermal Reservoirs Based on Acid Fracturing Modification","authors":"Xinghui Wu, Peng Li, Shengjun Miao, Meifeng Cai, Yan Liu, Min Wang, Wensai Xiong","doi":"10.1016/j.csite.2025.106591","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106591","url":null,"abstract":"Efficient development of deep carbonate thermal reservoirs is crucial for geothermal resource utilization, but their low permeability and long-term thermal decay problems seriously limit their capacity. Taking the D22 well in Xiongan New Area as an example, we constructed a multi-field coupled Thermo-Hydro-Mechanical-Chemical (THMC) numerical model. We revealed the heat exchange mechanism and heat attenuation law of the reservoir after acid fracturing and reforming. The study shows that increasing the acid fracture opening from 0.08 m to 0.12 m increases permeability by 35% and heat exchange efficiency by 20%, but the increase in opening accelerates the cold front advance and leads to fracture closure. The main control parameters of fracture opening, well distance, and injection flow rate were identified, and the \"stepped dynamic flow rate control method\" was proposed to adjust the flow rate in steps (200→160→120 m<ce:sup loc=\"post\">3</ce:sup>/h), which reduced the temperature decay rate by 42% and increased the cumulative heat extraction by 18%. Further design of a 10-12 mm nano-aerogel wellbore thermal barrier coating reduces heat loss by 15% and extends system life by 2-3 years after synergistic optimization. For large-scale reservoir development, \"medium reservoir size (3-4 km<ce:sup loc=\"post\">2</ce:sup>) periodic acid recharge\" is proposed to suppress the diminishing marginal benefits.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"10 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144503928","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

Experimental evaluation of a high temperature cascade heat pump based on refrigerant charge 基于制冷剂充注的高温叶栅热泵实验评价

IF 6.8 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-26 DOI: 10.1016/j.csite.2025.106573

Xuelian Ma, Yue Fang, Qian Dai, Zhonglu He, Junlan Yang, Jingmeng Liu, Hongfu Zou

{"title":"Experimental evaluation of a high temperature cascade heat pump based on refrigerant charge","authors":"Xuelian Ma, Yue Fang, Qian Dai, Zhonglu He, Junlan Yang, Jingmeng Liu, Hongfu Zou","doi":"10.1016/j.csite.2025.106573","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106573","url":null,"abstract":"Global energy demand continues rising with technological advancement. Renewables like solar and wind are increasingly adopted, yet heating/cooling systems responsible for 40 % of building energy use require urgent efficiency improvements. Heat pumps emerge as key solutions, particularly cascade systems. Refrigerant charge in cascade Heat pumps is critical: overcharging raises costs and leakage risks, while undercharging reduces heating capacity. To investigate the effect of refrigerant charge on the performance of the High-Temperature Cascade Heat Pump (HTCHP) system, a 20 kW HTCHP test rig was constructed. Several experiments were conducted to examine the variations in pressure, power input, heating capacity, and coefficient of performance (COP) with different refrigerant charge amounts in the Low-Temperature End Refrigeration Cycle (LS). An uncertainty analysis was performed to ensure the accuracy and reliability of the experimental results. The findings reveal that the evaporating and condensing pressures in both the LS and High-Temperature End Refrigeration Cycle (HS), as well as the power input of LS, heating capacity, and COP, increased with the refrigerant charge in LS. In contrast, the power input of HS showed little change. The HTCHP COP decreased by approximately 3.25 %–5.77 % as the refrigerant charge in LS increased by 300 g.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"23 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144503934","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

Analysis of inlet temperature, pressure, and channel design effect on cryogenic methane evaporation in minichannel PCHEs 入口温度、压力和通道设计对小通道PCHEs低温甲烷蒸发的影响分析

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-06-26 DOI: 10.1016/j.csite.2025.106517

Nyein Nyein Aye, Withun Hemsuwan, Chalothorn Thumthae

{"title":"Analysis of inlet temperature, pressure, and channel design effect on cryogenic methane evaporation in minichannel PCHEs","authors":"Nyein Nyein Aye, Withun Hemsuwan, Chalothorn Thumthae","doi":"10.1016/j.csite.2025.106517","DOIUrl":"10.1016/j.csite.2025.106517","url":null,"abstract":"<div><div>The thermal-hydraulic performance of Printed Circuit Heat Exchangers (PCHEs) with minichannels plays a crucial role in liquefaction and vaporization processes within the energy sector and diverse industrial applications, serving as a pivotal component in the secure treatment of cryogenic fluids. Computational fluid dynamics (CFD) simulation was needed to do systematic analysis for the development of thermal hydraulic performance PCHEs in cryogenic applications. In this study, CFD simulations using the Volume of Fluid (VOF) method were employed to systematically investigate two-phase flow simulation in minichannel PCHEs. The effects of fluid pressure and inlet temperature on the cryogenic methane evaporation was studied, showing that lower inlet pressure and temperature increased evaporation rates. Nucleate boiling dominated at 0.1 MPa, while convective boiling occurred at higher pressures (0.7–1 MPa). Geometric analysis showed that smaller channel (D = 0.884 mm) enhanced heat transfer but caused higher pressure drops, while larger channels (D = 2–3 mm) reduced pressure losses and increased vapor generation, though with lower heat transfer coefficients. Furthermore, new zigzag channel design, based on previous research, was proposed to enhance evaporation by promoting higher turbulence, mixing, and heat transfer rates compared to straight channel. This study also reviewed the effects of various working fluids and channel geometries including channel shapes (zigzag, straight) and cross-sectional profiles (rectangular, circular, semicircular) on cryogenic evaporation performance. These results highlight how optimizing pressure, inlet temperature, and channel geometry can enhance vapor quality, heat transfer, and pressure drop performance in minichannel PCHEs for cryogenic applications.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"73 ","pages":"Article 106517"},"PeriodicalIF":6.4,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480389","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