Case Studies in Thermal Engineering最新文献

{"title":"Nanoparticle-Enhanced Cleaning Assessment Through Hydro-Thermo Modeling in Laundering of Woven Fabrics","authors":"Hossein Rezaei Shahi, Saeed Dinarvand, Mohammad Vahabi, Arash Mirabdolah Lavasani, Mohammad Nimafar","doi":"10.1016/j.csite.2025.106914","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106914","url":null,"abstract":"Understanding the interaction between cleaning agents and fabric at the microscale is essential for improving detergent efficiency and environmentally friendly. Advances in computational modeling offer powerful tools to analyze and optimize such sophisticated mechanisms without relying solely on experimental trials. The aim of this study is to numerically model the flow and heat transfer of nano-detergent through the pores of woven fabric in the presence of an oil stain. The nano-detergent consists of zinc oxide nanoparticles, which are widely used in the detergent industry, and a base fluid composed of water and a commercial detergent in an appropriate ratio. Since most fabrics use plain weave yarns, the openings created in this weave type are considered as the flow geometry. To ensure the results are practical and closely aligned with real applications, characteristics such as geometry, nano-detergent temperature, fabric temperature, and flow Reynolds number have been selected to reflect actual washing machine conditions. The key innovation of this study lies in both the unique geometric structure of the woven fabric and the application of a commercially available detergent as base fluid. In this computational fluid dynamics (CFD) modeling, performed using ANSYS Fluent, the nano-detergent is treated as a single phase due to the low concentration of nanoparticles, while the oil stain undergoes dissolution mass transfer. The governing equations for fluid dynamics in this study are based on the incompressible Navier-Stokes equations, coupled with the volume of fluid (VOF) model to track the interface between the nano-detergent and oil stain phases. Given that both friction and heat transfer influence the stain removal properties of the nano-detergent, they have been calculated and analyzed. The friction factor and Nusselt number are presented for different Reynolds numbers, while velocity, temperature, and mass fraction contours of the oil stain are also plotted and discussed. Overall, the results indicate that in nano-detergents containing commercial concentrations (low concentrations) of zinc oxide nanoparticles, both heat transfer and the friction coefficient (key factors in enhancing stain removal) increase. However, the enhancement in heat transfer is minimal, making abrasion the more effective mechanism for stain removal. Quantitative and qualitative results, along with physical analysis and details, can be found in the text of the article.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"11 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899910","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}

{"title":"Direct contact condensation of two-phase ammonia in the co-current subcooled liquid flow at the low mass fluxes","authors":"Vasyl Ruzaikin, Ivan Lukashov, Andrii Breus, Olena Torosian","doi":"10.1016/j.csite.2025.106922","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106922","url":null,"abstract":"The paper presents a brief sensitivity study of direct contact condensation in the co-current flow of subcooled anhydrous ammonia. Two nozzles with inner diameters of 1.4 mm and 2.5 mm were tested under various conditions, including saturation pressures ranging from 11.7 to 23.1 bar, vapour qualities from 0.2 to 1.0, and vapour mass fluxes between 450 and 1300 kg m<ce:sup loc=\"post\">−2</ce:sup>s<ce:sup loc=\"post\">−1</ce:sup>. The condensation process was visually examined in a transparent tube with an inner diameter of 7.5 mm. The observed condensation front enabled the determination of average plume length under different boundary conditions and the estimation of conservative condensation heat transfer coefficients. The results indicate that existing models and correlations—primarily developed from steam-water experiments—fail to adequately predict ammonia condensation behaviour, both qualitatively and quantitatively. This comparison highlights the need for a robust phenomenological theory of the direct contact condensation mechanism. The study identifies the vapour Reynolds number as the primary factor influencing ammonia condensation intensity. A new phenomenological correlation is proposed, adequately capturing the experimental data within a ±30 % margin.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"94 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899980","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}

{"title":"Study on thermal characteristics of LiCoxNiyMn1-x-yO2-LiFePO4 mixed battery pack","authors":"Zheng Chen, Jingyuan Hu, Jiangwei Shen, Yonggang Liu, Yuanjian Zhang, Yu Liu, Fuxing Wei, Dehai Zhang","doi":"10.1016/j.csite.2025.106919","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106919","url":null,"abstract":"To address the limitations of single-system lithium-ion battery packs, industry has developed a dual-system design integrating ternary lithium batteries with the lithium iron phosphate batteries commonly employed in vehicles. Given the differing thermal characteristics of these batteries, a comprehensive study of thermal management of mixed battery packs is essential for ensuring safe operation. This study compares four different air-cooling battery thermal management system (BTMS) structures—Z-type, I-type, Y-type, and T-type—through a simulation model validated by experimental data. Furthermore, the research explores heat generation differences between the two types of batteries and their impact on layout optimization, with comparative simulations under two airflow scenarios guiding the optimal arrangement for improved cooling. Among the designs, the BTMS-Z exhibits the best overall cooling performance, as shown by maximum temperature, average temperature, and maximum temperature difference at various airspeeds. Furthermore, a full-factorial design of experiments is employed to systematically study the effects of air vent width, flow channel length, and battery spacing on thermal performance. Analysis of variance identifies air inlet width as the most influential factor. Finally, a genetic algorithm is applied for multi-parameter structural optimization, achieving reductions of 2.39% in <ce:italic>T</ce:italic><ce:inf loc=\"post\"><ce:italic>max</ce:italic></ce:inf>, 3.69% in <ce:italic>T</ce:italic><ce:inf loc=\"post\"><ce:italic>ave</ce:italic></ce:inf>, 3.78% in <ce:math altimg=\"si1.svg\"></ce:math>, and 40.35% in volume, which significantly enhances cooling efficiency and reduces BTMS spatial occupancy.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"48 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899909","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}

{"title":"A new design of regenerative flow turbine with improved performance for residential applications","authors":"Alperen Bugra Colak, Oğuz Arslan","doi":"10.1016/j.csite.2025.106923","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106923","url":null,"abstract":"Regenerative flow turbines (RFTs) are increasingly used for power generation in small-scale applications such as residential use. Although they are adequate for the use of waste energy, the efficiency of RFTs still needs to be improved. This study investigates the performance improvement of the conventional RFT (α = 0°) by optimizing the blade geometry to obtain the maximal momentum transfer. Computational fluid dynamics (CFD) analyses were conducted for low temperatures of 363 K and 393K and high temperatures of 475 and 500K, as available for residential use. The performance of the designs and formed ORC was evaluated through energy and exergy analyses. As a result, it was determined that it is possible to increase the maximum power generation from 0.81 kW to 0.89 kW by an increase rate of 9.42 % for high-temperature scales, while it is possible to increase the maximum power generation from 0.21 kW to 0.23 kW by an increase rate of 9.71 % for low-temperature scales. It was determined that it is possible to increase energy efficiency from 11.26 % to 14.72 % by a rate of 30.73 % and exergy efficiency from 10.77 % to 12.54 % by 16.49 % for low-temperature applications. Also, it is available to increase energy efficiency from 12.16 % to 14.67 % by an increase rate of 20.64 %, and exergy efficiency from 6.80 % to 7.99 % by an increase rate of 17.45 % for high-temperature applications. These results record an exergy efficiency increase of up to 0.205 pp at 1500 rpm and up to 0.420 pp at 3000 rpm for a low-temperature ORC system. For the high-temperature applications (475–500K), an increase in the exergy efficiency up to 0.129 pp is available.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"28 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899911","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}

{"title":"Quadruple Generation of Power, Refrigeration, Freshwater, and CO2 Capture via Chemical Looping Combustion and Coupled Thermodynamic Cycles","authors":"Farzin Javanfam, Samad Jafarmadar, Sina Salehi, Morteza Khalilian","doi":"10.1016/j.csite.2025.106910","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106910","url":null,"abstract":"This study proposes and evaluates an innovative multi-generation cogeneration system that simultaneously produces electricity, cooling, freshwater, and captures CO<ce:inf loc=\"post\">2</ce:inf>, utilizing a highly efficient thermal cascade driven by chemical looping combustion (CLC). The system integrates one inverse Brayton cycle (IBC), three conventional Brayton cycles, two organic Rankine cycles (ORCs), and two steam Rankine cycles (SRCs), achieving a total power output of 2,500 kW at a methane fuel flow rate of 0.075 kg/s. Waste heat recovery enables the operation of an evaporative desalination system (EDS), producing 0.1789 kg/s of high-purity water, and an absorption refrigeration system delivering 13.68 kW of cooling. The CLC configuration inherently captures 0.2 kg/s of CO<ce:inf loc=\"post\">2</ce:inf>, contributing to integrated carbon management. Detailed thermodynamic and exergy analyses reveal energy and exergy efficiencies of 77.85% and 66.61%, respectively—figures that significantly outperform traditional cogeneration systems. Sankey diagram analysis indicates that 79.34% of the input exergy is converted into useful outputs, while 17.43% is destroyed, primarily in the CLC unit due to combustion irreversibilities. Parametric studies highlight operational trade-offs: increasing fuel flow or pressure improves power output but may reduce water and cooling yields or overall efficiency. This integrated design addresses four pressing global challenges—clean energy generation, water scarcity, climate change mitigation, and thermal comfort—within a single, compact system. The results demonstrate the system’s potential as an efficient solution for future energy infrastructure, offering enhanced resource utilization and minimal environmental impact.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"11 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899985","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}

{"title":"Numerical study on the heating performance of a passive system of solar chimney coupled with earth-air heat exchanger","authors":"Wuyan Li, Yuanxiu Gong, Lu Wang, Linfeng Wang, Tingting Leng, Zixiong Qin, Yongcai Li, Zheli Xing","doi":"10.1016/j.csite.2025.106916","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106916","url":null,"abstract":"The Solar Chimney Coupled with Earth-Air Heat Exchanger (<ce:italic>SCEAHE</ce:italic>) system is a promising low-carbon solution for building climate control, leveraging soil thermal storage and solar-induced thermal pressure. However, its widespread adoption is hindered by limited heating capacity during winter, primarily due to the soil's constrained heat exchange potential. To address this critical limitation, this study improved the conventional <ce:italic>SCEAHE</ce:italic> system, wherein solar energy is dual-purposed: not only to drive thermal pressure but also to directly supplement heating. A comprehensive numerical model coupling the enhanced system with a building was developed, and its performance was rigorously evaluated under winter weather conditions of Beijing, China. Through comparative analysis with the conventional system, the results demonstrate that the improved system significantly enhances thermal performance: indoor temperatures increased by 6.3 °C (daytime) and 1.6 °C (night time) over a typical heating week. These improvements were accompanied by dynamic airflow adjustments, with daytime ventilation rates decreasing by 15.0 % (reducing heat loss) and night time rates increasing by 13.8 % (enhancing soil heat recovery). Furthermore, when integrated with auxiliary heating, the enhanced system reduced supplemental heating demand by 26.5 % while maintaining ventilation efficiency (only 5.0 % reduction), underscoring its potential to lower energy consumption.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"100 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899989","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}

{"title":"3-D modeling for simultaneous heat and mass transfer in fixed-bed drying of soybean grains applying CFD code","authors":"A.R. Visconcini, M. Souza, A.M.S. Costa","doi":"10.1016/j.csite.2025.106899","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106899","url":null,"abstract":"This study developed a computational code for coupling heat and mass transfer phenomena with fluid dynamics in soybean drying using air as the heated gas. The modeling was designed using computational fluid dynamics (CFD) techniques using the Fluent 21. R1 software, incorporating the user-defined functions (UDF) written in C language. The drying was developed in a fixed bed considered a porous medium, applying the thermal non-equilibrium mathematical model with the drying kinetics for thin-layers. The constitutive and property equations were developed for soybeans, air, and vapor. The proposed model was solved numerically considering the governing equations in the 3-D domain. The simulated results were compared to the experimental data obtained, where the relative error (RE) was less than 4.9 % for soybean moisture and less than 1.7 % for soybean and air temperatures, while the mean relative deviation (MRD) was less than 4.5 and 1.2 % for the same respective parameters. The behavior of the moisture and temperature of the soybeans, and the air temperature show a good correlation with the experimental data throughout the drying process, while the results obtained for the absolute air humidity behavior reinforce the coherence with the 3-D drying model, which reflects a good agreement for the simulations carried out.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"25 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899991","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}

{"title":"Effect of one-dimensional simplification of ground heat exchanger on prediction errors of numerical thermal response test","authors":"Kun Zhou, Yong Li, Weizhi Wei, Zhenghao Jin, Mingzhou Xia, Zengxi Li","doi":"10.1016/j.csite.2025.106911","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106911","url":null,"abstract":"Numerical thermal response test (TRT) emerges as a powerful alternative to traditional in-situ TRT. This study aimed to analyze the prediction errors of numerical TRT model caused by one-dimensional (1D) simplification of GHE. The numerical TRT model incorporating virtual pipe was developed to address limitations of 1D pipe. Additionally, the numerical TRT model based on 1D GHE simplification without virtual pipe was established for comparison. The fluid outlet, borehole surface, and soil temperature from both models were compared with experimental data to quantify prediction errors of simplified numerical TRT models. The impacts of borehole configurations and material thermal properties on prediction errors were further analyzed considering test discrepancies. The results reveal that incorporating virtual pipe in the numerical TRT model significantly improves the accuracy of numerical TRT results, with enhancements reaching up to 94.83%. The prediction errors increase with pipe diameter, heat injection rate, and soil thermal conductivity, but decrease with borehole diameter and grout thermal conductivity. The heat injection rate is the most influential factor, and grout thermal conductivity, borehole diameter, pipe diameter, and soil thermal conductivity are significant contributory factors to the prediction errors. The effects of borehole depth, pipe thermal conductivity, and test duration on errors can be neglected.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"22 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899984","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}

{"title":"Study on the smoke transportation rule and the cooperative smoke removal effect of fire in an ultra-long submarine tunnel","authors":"Song Xin, Yuan Li, Shangxiao Liu, Caihua Shi","doi":"10.1016/j.csite.2025.106909","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106909","url":null,"abstract":"To address the challenges of smoke extraction during fire incidents in ultra-long submarine tunnels, this study investigated the smoke transport dynamics in the second submarine tunnel of Jiaozhou Bay. A quantitative assessment was performed to analyze the influence of variables such as fire source heat release rate, spacing between exhaust outlets, and the aspect ratio of exhaust vents. Findings indicate that at a fire power of 50 MW, optimal smoke extraction efficiency is achieved with an exhaust outlet aspect ratio of 6 × 1 and a spacing of 35 m. Nonetheless, smoke dispersal from the fire source remains extensive, hindering effective personnel evacuation. To mitigate this, a rapid smoke control strategy integrating horizontal and vertical ventilation is proposed. This coordinated exhaust approach reduces the average upstream smoke spread by 120 m, lowers tunnel temperature by 47.37 %, decreases CO concentration by 33.3 %, and significantly mitigates the risk of toxic exposure. The outcomes offer a novel framework for enhancing emergency smoke management in ultra-long submarine tunnel environments.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"30 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899990","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}

{"title":"Thermal behavior of magnetized blood–CMS hybrid nanofluid with SWCNT and MWCNT suspensions: Prabhakar fractional model","authors":"Urwa Shehbaz, Sami Ullah Khan, Aboulbaba Eladeb, Nermeen Abdullah, Chemseddine Maatki, Lioua Kolsi","doi":"10.1016/j.csite.2025.106890","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106890","url":null,"abstract":"This analysis investigates natural convective (mixed convection) hybrid nanofluid (HNF) flow within a channel by using advanced definitions of fractional operators. The hybrid nanofluid consists of single-walled and multi-walled carbon nanotubes (SWCNTs-MWCNTs) dispersed in blood and carboxymethyl starch (CMS) base fluids. The fractional computations are performed with help of Prabhakar fractional model. The Laplace transformed is implemented to governing equations involving the Prabhakar operator, the Stehfest numerical inversion algorithm is implemented to retrieve the time-domain computations. Such approach ensures the accurate implementation of Laplace transport to evaluate the effective thermal and flow fields. A detailed comparative analysis is conducted to ensure the validity of fractional model. The findings indicate that blood-based hybrid nanofluids exhibit a more pronounced influence on thermal and momentum transport compared to CMS-based nanofluids, making them more effective for biomedical and industrial heat transfer applications.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"51 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899993","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}