Case Studies in Thermal Engineering最新文献

{"title":"Williamson nanofluid aspects on fluctuating radiative heat and mass transfer with viscous dissipation along heat exchanger plate in nuclear-power plants","authors":"Zia Ullah ,&nbsp;Md Mahbub Alam ,&nbsp;Essam R. El-Zahar ,&nbsp;Sana Shahab ,&nbsp;Hanaa Abu-Zinadah ,&nbsp;Abdelhalim Ebaid ,&nbsp;M.D. Alsulami ,&nbsp;Laila F. Seddek","doi":"10.1016/j.csite.2025.106176","DOIUrl":"10.1016/j.csite.2025.106176","url":null,"abstract":"<div><div>Thermal transport and mass/concentration transfer through heat exchanger vertical plate is important component of nuclear power reactor for heat transfer in primary coolant loop to secondary loop. These loops generate stream in turbine to generate electricity energy. In nuclear power reactors, the heat exchanger plate provides enhanced cooling. The fluctuations and turbulence behavior of heat-mass transfer of oscillatory Williamson nanofluid over the heated surface with viscous dissipation, thermophoresis, and nonlinear radiating heat effects. Mathematical model is developed for unsteady flow to discuss the steady profiles and shifting amplitude of periodical heat/thermal and mass-concentration transport. The fluctuating Stokes conditions are applied to change the steady and fluctuating model into real/imaginary equations. Real, steady and imaginary models are transformed through primitive transformations to create the similarity in all equations under FORTRAN language. For asymptotic and fluctuating results of heat and mass transfer, the Gaussian elimination approach is used through implicit finite difference technique for programming algorithm. The velocity streamlines and isothermal lines are plotted along the heat exchanger plate for Eckert number (<span><math><mrow><msub><mi>E</mi><mi>c</mi></msub></mrow></math></span>), radiation parameter (<span><math><mrow><msub><mi>R</mi><mi>d</mi></msub></mrow></math></span>), thermophoresis (<span><math><mrow><msub><mi>N</mi><mi>T</mi></msub></mrow></math></span>) and Weissenberg number (<span><math><mrow><mi>W</mi></mrow></math></span>). The steady profiles of skin friction, heat transfer and mass rate are examined and then used in oscillatory formula to draw the periodical-skin friction, periodical heat transfer and periodical-mass rate with amplitude and turbulent effects. It is found that magnitude streamlines and isothermal lines increases as radiation parameter increases. The high fluctuations and turbulence in heat and mass transfer is noted for maximum thermophoresis and radiation parameter with greater amplitude.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"71 ","pages":"Article 106176"},"PeriodicalIF":6.4,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858768","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":"Influence of magnetic fields on the thermal conductivity, electrical conductivity, and viscosity of iron-encapsulated multi-walled carbon nanotubes","authors":"Mohammad J. Akbar ,&nbsp;Adil Farooq Wali ,&nbsp;Sirajunisa Talath ,&nbsp;Abdullah Aljasser ,&nbsp;Mohammed M. Aldurdunji ,&nbsp;Fahad Alqahtani ,&nbsp;Sathvik B. Sridhar ,&nbsp;M. Yasmin Begum ,&nbsp;Umme Hani","doi":"10.1016/j.csite.2025.106166","DOIUrl":"10.1016/j.csite.2025.106166","url":null,"abstract":"<div><div>This study explores the thermal, electrical, and dynamic viscosity properties of water-based Fe@MWCNT nanofluids, both with and without the influence of an external magnetic field, offering novel insights into the behavior of magnetic nanofluids. The research demonstrates that Fe@MWCNT nanofluids exhibit unique magnetic-responsive characteristics, with thermal conductivity showing a remarkable dependence on external magnetic fields, temperature, and volume concentration. A key finding is the 25 % enhancement in thermal conductivity achieved at a volume concentration of 0.4 % and a temperature of 323.15 K under a 0.05 T magnetic field, a significant advancement in the field of nanofluid-based thermal management. In terms of electrical conductivity, the nanofluids display a tunable range between 530 and 1600 μS/cm as the volume concentration varies from 0.1 % to 1 %. This conductivity is further modulated by temperature and magnetic fields, with increases of 5 %–30 % under 0.05 T and 30 %–70 % under 0.1 T, showcasing the potential for precise control in applications requiring adaptive electrical properties. The dynamic viscosity of the nanofluids, ranging from 0.6 to 1.2 mPa s, is intricately linked to volume concentration, temperature, and magnetic field strength. Notably, the application of a magnetic field can increase viscosity by up to 50 %, a finding that underscores the unique magneto-rheological behavior of Fe@MWCNT nanofluids. This work advances the state of the art by providing a comprehensive understanding of the interplay between magnetic fields, temperature, and nanofluid composition, offering new opportunities for the design of advanced thermal management systems and magnetically tunable fluid technologies. The results highlight the originality of the research, particularly in demonstrating the significant enhancements in thermal and electrical properties under magnetic fields, which have not been extensively explored in previous studies.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"71 ","pages":"Article 106166"},"PeriodicalIF":6.4,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873112","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":"Experimental investigation of synergistic additives in enhancing water mist suppression of engine oil fires","authors":"Ye-Cheng Liu ,&nbsp;Zhi-Xiang Xing ,&nbsp;Yan Tang ,&nbsp;Fang-Chao Cao ,&nbsp;Xin-Yue Ma ,&nbsp;Long-Tai Qi ,&nbsp;An-Chi Huang","doi":"10.1016/j.csite.2025.106175","DOIUrl":"10.1016/j.csite.2025.106175","url":null,"abstract":"<div><div>This study investigates the mechanisms and efficacy of water mist (WM) in suppressing engine oil fires. The incorporation of additives, particularly surfactants, enhances the physical and chemical properties of WM, enabling it to emulsify and infiltrate engine oil products more effectively. This optimization of droplet dimensions improves atomization efficiency, fire suppression performance, and emulsification capabilities, resulting in a highly efficient aqueous fire-extinguishing system. Among the additives studied, alkali metal salt NaCl has been extensively researched. To evaluate the synergistic effects of composite surfactants, this study compares the performance of composite anionic-nonionic surfactants with NaCl salts and pure WM systems. The results of oil pool fire experiments showed that the improvement effects of additives NaCl and LAS-FMEE (1:1) on the WM system were 18.39 % and 22.99 %, respectively. The screened composite surfactant fire extinguishing agent demonstrates superior enhancement effects on WM (water-mist) fire extinguishing compared to metal salts, effectively reducing toxic CO gas production in combustion systems. Additionally, omposite surfactants significantly enhance fire suppression efficiency, offering a promising approach for improving WM-based fire extinguishing technologies.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"71 ","pages":"Article 106175"},"PeriodicalIF":6.4,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855940","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":"Investigation of CL-20/NEPE propellant: thermal decomposition, ignition and combustion characteristics","authors":"Chengyin Tu","doi":"10.1016/j.csite.2025.106147","DOIUrl":"10.1016/j.csite.2025.106147","url":null,"abstract":"<div><div>CL-20/NEPE propellants, due to their high energy levels, superior combustion performance, and low signature characteristics, hold significant application value in the field of propellant technology. However, their thermal decomposition, ignition and combustion characteristics are highly complex, necessitating a deeper understanding. In this study, a thermal gravimetric analyzer was deployed to study the thermal decomposition characteristics of CL-20/NEPE propellant, and then a high-pressure combustion chamber was established to observe the ignition process and combustion characteristics. The thermal decomposition of CL-20/NEPE propellant was observed to occur in three phases: low-temperature rapid mass loss stage (50 °C–280 °C), medium-temperature slow mass loss stage (290 °C–400 °C), and high-temperature slow mass loss stage (400 °C–500 °C). The propellant undergoes five phases during ignition and combustion: initial flame formation, flame diffusion, steady combustion, flame recession, and flame extinction. The microstructure of condensed combustion products post-combustion was analyzed using a scanning electron microscope, we broadly categorized the CCPs into three types according to their morphology. Finally, we constructed an agglomeration model predicated on the pocket model to forecast aluminum agglomerate sizes within CL-20/NEPE propellant. The experimental data closely match the model's predictions, validating the model's efficacy in agglomeration prediction for this propellant.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106147"},"PeriodicalIF":6.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850120","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":"Fire evacuation strategies for traditional public markets in an aging society","authors":"Chih-Hao Hsu,&nbsp;Carol C. Wu,&nbsp;Kai-Min Liao","doi":"10.1016/j.csite.2025.106156","DOIUrl":"10.1016/j.csite.2025.106156","url":null,"abstract":"<div><div>Traditional public markets in Taiwan are unique in that they mimic markets in traditional agricultural societies, offering convenient access to diverse goods and services. Many are in enclosed indoor spaces and have vendors that provide complex services requiring kitchens or other equipment; this increases both crowding and fire risk. They have few entrances and exits, densely packed stalls, narrow walkways, and poor signage. These all suggest a high risk of a crowd crush accident during an emergency evacuation, and effective improvements are urgently needed. In this study, improvements to evacuations were investigated through spatial dynamic simulation. A representative two-floor market was modeled, and on-site surveys were performed to identify customer behavior and demographics. The fire simulation software PyroSim was used to simulate a fire in the market to identify the maximum evacuation time before safe temperature, smoke, carbon monoxide, or visibility limits were exceeded. The collected on-site data were used to simulate an evacuation for a crowd with pedestrians of various ages and genders in Pathfinder software. The evacuation time, crowd density, and exit signage were evaluated, and improvements based on the results were proposed and validated.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"71 ","pages":"Article 106156"},"PeriodicalIF":6.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852153","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":"Investigation of a novel heat extraction configuration for boosting photovoltaic panel efficiency","authors":"Muhammad Usman ,&nbsp;Hafiz Waqar Ul Haq ,&nbsp;Fahid Riaz ,&nbsp;Muhammad Sher Ali ,&nbsp;Muhammad Imran Masood ,&nbsp;Yasser Fouad ,&nbsp;Shahmeer Khalid Chatha ,&nbsp;Muhammad Nasir Bashir","doi":"10.1016/j.csite.2025.106104","DOIUrl":"10.1016/j.csite.2025.106104","url":null,"abstract":"<div><div>This study investigates the impact of accumulated heat extraction on photovoltaic (PV) panels' performance and longevity using Computational Fluid Dynamics (CFD) simulations. Three distinct cooling configurations were analyzed including thermoelectric cooling with a Peltier module, water cooling with a Peltier module, and a hybrid system combining thermoelectric and water cooling. Thermoelectric cooling with a Peltier module resulted in an 8.68 % efficiency loss. Water cooling demonstrated a 5.42 % increase in efficiency by effectively reducing operating temperatures. The hybrid system achieved the best results, with a 17.64 % efficiency increase. This research supports United Nations Sustainable Development Goals (SDGs), including affordable and clean energy (SDG 7), economic growth (SDG 8), innovation and infrastructure (SDG 9), sustainable cities (SDG 11), and climate action (SDG 13). Future work could enhance PV panel performance by using extracted heat for domestic water heating or industrial processes and optimizing cooling techniques through a parametric study and real-time machine learning models.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106104"},"PeriodicalIF":6.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850181","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":"Experimental evaluation of a novel photovoltaic thermal System: Energy, economic, and exergy-based sustainability analysis","authors":"Hariam Luqman Azeez ,&nbsp;Adnan Ibrahim ,&nbsp;Banw Omer Ahmed ,&nbsp;Sharul Sham Dol ,&nbsp;Ali H.A. Al-Waeli ,&nbsp;Mahmoud Jaber","doi":"10.1016/j.csite.2025.106167","DOIUrl":"10.1016/j.csite.2025.106167","url":null,"abstract":"<div><div>Photovoltaic systems encounter significant thermal challenges, which can impact their efficiency. To tackle this issue, Photovoltaic Thermal systems have been proposed. However, low thermal efficiency is a recurring theme with these systems in the current literature. Therefore, this study proposes the development of a thermal collector incorporating dimples and petal arrays on both the inner and outer surfaces of the absorber tube. Additionally, the system utilizes nanofluid and nano-enhanced phase change materials to further enhance thermal efficiency. Through outdoor experiments, the performance of seven photovoltaic modules is assessed using various cooling mechanism. The result demonstrates that the best design which includes the new collector design, nanofluid, and nanophase changing materials enhances electrical and thermal efficiencies by 34.44 % and 27.94 %, respectively compared to a standard photovoltaic thermal system which employs smooth tube and water. Despite the fact that the new design increases energy demand throughout its lifespan by 4.8 % compared to the standard photovoltaic thermal system, it increases energy production overall life cycle by 27.09 %, resulting in 21.20 % enhancement in energy payback time. Finally, the best design reduces improvement for potential (potential loss) by 10.28 % compared to standard photovoltaic thermal system.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"71 ","pages":"Article 106167"},"PeriodicalIF":6.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873113","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":"Chaotic flow in a closed-loop pulsating heat pipe","authors":"Weixiu Shi ,&nbsp;Haiyu Chang ,&nbsp;Hongdi Chen ,&nbsp;Lisheng Pan","doi":"10.1016/j.csite.2025.106162","DOIUrl":"10.1016/j.csite.2025.106162","url":null,"abstract":"<div><div>The wall temperature pulsating of pulsating heat pipes using ultrapure water and phase change microcapsule fluids is tested by experiments and the temperature signals are processed by numerical calculation methods. The chaotic characteristics of vapor-liquid two-phase pulsating are analyzed through chaotic attractors, delay time, embedding dimension, and correlation dimension. It is found that The increasing of concentration of phase change microcapsule fluid weakens the periodicity of temperature pulsating, and the randomness of temperature pulsating can reflect the chaotic characteristics. The distribution of attractors is related to temperature pulsating and can reflect the running of PHPs. The temperature stability of the evaporation section and distribution concentration of attractors gradually increases with the heating power increasing, which shows the better heat transfer performance. The attractor distribution shows a divergent state with larger amplitude and lower frequency because of the less heating power, and the attractors present compact cluster distribution with different delay times because of the higher heating power, indicating that the time series cannot be fully expanded with the lower embedding dimension, and it is necessary to describe the running of working fluid with the higher dimensional space. The delay time roughly shows a decreasing trend with increasing of heating power. The embedding dimension of PHP using phase change microcapsules as working fluid has a higher value than that of ultrapure water during the running, which may be due to the disturbance effect of phase change microcapsule particles. The saturation correlation dimension of the PHP is slightly greater with heating power increasing. The higher the correlation dimension, the more factors that affect the heat transfer of PHPs, which indicate that the more complex running, the stronger sustainability and the better heat transfer.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"71 ","pages":"Article 106162"},"PeriodicalIF":6.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858691","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":"Compensating cooling on the suction surface of the blade by the jets of the film holes on the endwall","authors":"Changyu Zhao (赵长宇),&nbsp;Junyu Zhu (朱俊羽),&nbsp;Wei Zhang (张魏),&nbsp;Zhiqi Zhao (赵志奇),&nbsp;Guangchao Li (李广超),&nbsp;Chun Li (李春)","doi":"10.1016/j.csite.2025.106174","DOIUrl":"10.1016/j.csite.2025.106174","url":null,"abstract":"<div><div>The coolant ejected from the film holes on the gill region of the blade deflects to the blade tip in the action of the cascade passage vortices, resulting in the local film cooling failure on the suction surface near the endwall. This paper introduces an improved strategy for compensating the film cooling on the suction surface near the endwall by using the passage vortices to entrain coolant inject from endwall jet. The film effectiveness of two rows of film holes on the gill region was measured by pressure-sensitive paint (PSP) technique to be as the baseline. Film hole layouts on the endwall were examined, including 3 single-hole cases, 3 double-hole cases, and 1 three-hole case, totaling 7 film hole layouts. The compensating improvement of film cooling on the suction surface was examined at the blowing ratios ranging from 0.50 to 1.75. The mechanism of compensating cooling was analyzed by numerical simulation. The correction equation of compensating cooling was established based on the experimental data. The results show that the compensating film effectiveness of single-hole B or hole C is higher than that of single-hole A in the film failure region at all blowing ratios. Single-hole C exhibits a significant improvement in film effectiveness by 0.032 at the high blowing ratio of 1.75. The film effectiveness of the combination of hole B and hole C is higher than those of the other combinations, with the largest improvement of film effectiveness by 0.028 at the blowing ratio of 1.75.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"71 ","pages":"Article 106174"},"PeriodicalIF":6.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873116","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":"Transparent smart radiation device for efficient thermal management of spacecraft solar cells","authors":"Biyuan Wu ,&nbsp;Xiqiao Huang ,&nbsp;Xiaohu Wu","doi":"10.1016/j.csite.2025.106161","DOIUrl":"10.1016/j.csite.2025.106161","url":null,"abstract":"<div><div>In space, spacecraft face extreme temperature fluctuations that threaten their performance and stability. Variable emissivity coatings offer an effective solution for radiative thermal management. However, balancing high visual transparency with thermal radiation control remains a significant challenge, especially for applications like spacecraft solar cells. In this study, we propose a multilayer planar transparent smart radiation device (TSRD) based on thermochromic material, thin metal and indium tin oxide (ITO). The effect of different substrates on TSRD performance is systematically investigated. Balancing the performance of TSRD across various spectral bands, the VO₂/BaF₂/ITO/Ag/ITO structure demonstrates superior performance among the three cases. Specifically, it achieves transmission of 0.8 and 0.72 in the visible spectrum under high- and low-temperature conditions, respectively, a solar absorption of only 0.16, and an emission modulation of up to 0.51 in the infrared band. Moreover, the addition of a lossless dielectric layer as a protective coating not only preserves the excellent performance of the TSRD but also holds the potential to enhance its durability and lifespan. This work provides a promising strategy for multispectral modulation and offers an effective solution for spacecraft solar cells thermal management.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"71 ","pages":"Article 106161"},"PeriodicalIF":6.4,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852152","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}