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

Advancing thermal energy storage: Unravelling the optimal orientation of annular phase change material containers within the tank

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-21 DOI: 10.1016/j.csite.2025.105931

Houssam Eddine Abdellatif , Ahmed Belaadi , Adeel Arshad , Boon Xian Chai , Ibrahim M.H. Alshaikh , Djamel Ghernaout

{"title":"Advancing thermal energy storage: Unravelling the optimal orientation of annular phase change material containers within the tank","authors":"Houssam Eddine Abdellatif , Ahmed Belaadi , Adeel Arshad , Boon Xian Chai , Ibrahim M.H. Alshaikh , Djamel Ghernaout","doi":"10.1016/j.csite.2025.105931","DOIUrl":"10.1016/j.csite.2025.105931","url":null,"abstract":"<div><div>This study investigates the efficiency of thermal energy storage (TES) systems employing phase change material (PCM) in tanks of different configurations. Six different distinct models of tanks are investigated numerically. The focus lies on analyzing temperature contours, liquid fraction contours, and specific enthalpy contours to understand the dynamic behavior of PCM during the phase change process. Particular attention is given to the placement of PCM containers about the inlet and outlet flow, ensuring optimal thermal interaction with the heat transfer fluid (HTF). The results indicate significant improvements in melting times compared to the baseline Model A, which has a cylindrical PCM container. Model B, incorporating annular PCM containers, achieves a notable reduction of 26.31 % in melting time, completing the melting process in 1680 s. With repositioned annular PCM containers at the tank's apex, Model C further enhances efficiency, achieving a 29.82 % reduction in melting time at 1600 s. Model D, featuring enhanced proximity between annular PCM containers, demonstrates a remarkable 31.57 % reduction, completing the melting process in 1560 s. Likewise, Model E, equipped with leftward inclined annular PCM containers, matches this reduction, achieving complete melting in 1560 s. Model F, incorporating a rightward inclination of annular containers, emerges as the most efficient, boasting a remarkable 33.33 % reduction in melting time, concluding the melting process in a mere 1520 s. These findings underscore the pivotal role of PCM container geometry, position, and inclination in optimizing heat transfer and PCM phase-change efficiency. The study provides valuable insights into designing and implementing PCM-based TES systems, offering a promising avenue for sustainable energy solutions.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105931"},"PeriodicalIF":6.4,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanism of thermal radiation, soret-dufour on ferromagnetic hybrid nanofluid through a permeable surface

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-21 DOI: 10.1016/j.csite.2025.105919

T. Radha Krishnaveni , G. Venkata Ramana Reddy , J. Anitha , G. Charan Kumar , N.R. Rajagopalan , Vediyappan Govindan , Haewon Byeon , Busayamas Pimpunchat

引用次数: 0

Optimization of the intermediate precooling temperatures for the 2 K hybrid cryocooler based on entropy generation analysis

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-20 DOI: 10.1016/j.csite.2025.105887

Bangjian Zhao , Shihang Ding , Lixi Lu , Zhen Yang , Guoliang Tang , Shijie Liu , Chunlai Li , Guangjun Dong , Jianyu Wang

{"title":"Optimization of the intermediate precooling temperatures for the 2 K hybrid cryocooler based on entropy generation analysis","authors":"Bangjian Zhao , Shihang Ding , Lixi Lu , Zhen Yang , Guoliang Tang , Shijie Liu , Chunlai Li , Guangjun Dong , Jianyu Wang","doi":"10.1016/j.csite.2025.105887","DOIUrl":"10.1016/j.csite.2025.105887","url":null,"abstract":"<div><div>There is an increasing demand for 2 K hybrid cryocoolers, consisting of a multi-stage Stirling-type pulse tube cryocooler (SPTC) coupled with a Joule-Thomson cooler (JTC), due to their critical applications in deep space exploration and quantum information technology. Precooling temperature and the number of precooling stages, as the key parameters of hybrid cryocoolers, are crucial for attaining 2 K cooling performance. In this paper, an entropy model of the JT cryocooler at 2 K temperature is established for the first time. Based on this model, three-stage precooling temperatures under various operating conditions are optimized, minimizing entropy generation and enhancing the energy utilization efficiency of the JTC cycle in the hybrid cryocooler. Results indicate that there is an optimal value for the first stage precooling temperature (<em>T</em><sub><em>pre.1</em></sub>) of 105 K, and the second-stage precooling temperature (<em>T</em><sub><em>pre.2</em></sub>) should be minimized. The third stage precooling temperature (<em>T</em><sub><em>pre.3</em></sub>) varies with the first two stages and is uniquely determined. Increasing precooling stages from two to three cuts entropy generation by about 15.12 %. These findings offer a key theoretical basis for optimizing hybrid cryocooler design and improving its efficiency and performance.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105887"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Advanced graph embedding for intelligent heating, ventilation, and air conditioning optimization: An ensemble learning-based recommender system

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-20 DOI: 10.1016/j.csite.2025.105888

Shouliang Lai, Xiyu Yi, Peiling Zhou, Lu Peng, Wentao Liu, Shi Sun, Binrong Huang

{"title":"Advanced graph embedding for intelligent heating, ventilation, and air conditioning optimization: An ensemble learning-based recommender system","authors":"Shouliang Lai, Xiyu Yi, Peiling Zhou, Lu Peng, Wentao Liu, Shi Sun, Binrong Huang","doi":"10.1016/j.csite.2025.105888","DOIUrl":"10.1016/j.csite.2025.105888","url":null,"abstract":"<div><div>This study introduces a robust and scalable software architecture designed for real-time data ingestion, processing, and user interaction within a smart building setting. Utilizing advanced graph embedding techniques combined with ensemble learning models, we developed a recommender system tailored for Heating, Ventilation, and Air Conditioning (HVAC) optimization in Shenzhen Qianhai Smart Community. We employed a mixed-methods approach, including the generation of synthetic multivariate time series data, data preprocessing, statistical correlation analysis, and the implementation of GraphSAGE, Graph Attention Networks (GAT), and Node2Vec for graph embedding. The ensemble learning framework integrated Decision Trees, Random Forests, Gradient Boosting Machines (XGBoost), and Neural Networks to enhance prediction accuracy. Our findings demonstrate that the proposed architecture maintains high performance under increased loads, with key sensor correlations effectively managed to optimize HVAC operations. The recommender system achieved a 51 % reduction in energy consumption of chilled water pumps and a 15 % increase in occupant satisfaction by providing personalized HVAC settings. These results highlight the significance of integrated system designs and data-driven strategies in developing intelligent building management solutions. The study contributes actionable insights into system scalability and user-centric environmental controls, paving the way for future research in real-world implementations and advanced analytical techniques.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105888"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Response surface methodology and sensitivity analysis of RP fluid model over curved stretching sheet: Non-similar investigation

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-20 DOI: 10.1016/j.csite.2025.105884

Mohammed Aldandani , Ahmed Jan

{"title":"Response surface methodology and sensitivity analysis of RP fluid model over curved stretching sheet: Non-similar investigation","authors":"Mohammed Aldandani , Ahmed Jan","doi":"10.1016/j.csite.2025.105884","DOIUrl":"10.1016/j.csite.2025.105884","url":null,"abstract":"<div><div>The transport performance for a convective non-Newtonian fluid model with heat transfer can be measured through skin friction coefficient, and Nusselt number. The aim of this study is to examine the sensitivity analysis of heat transfer and drag forces effects on magnetized Reiner-Philippoff fluid model over curved surface. The equations that regulate the flow issue are converted into a set of nonlinear dimensionless partial differential equations via a non-similarity transformation. These equations are treated as ordinary differential equations by employing the local non-similarity method up to second level truncation and simulated using MATLAB routine bvp4c. Prior to doing the sensitivity analysis of skin friction coefficient, and Nusselt number, we use response surface methods to construct empirical connections for these parameters. The empirical relations' quality of fit is determined using the analysis of variance table's coefficient of determination. The results show that coefficient of determination for skin friction coefficient, and Nusselt number are 100 %, 99.99 % and 97.73 % respectively. This means that we have obtained best fitted empirical relations. The results of sensitivity analysis disclosed that skin friction coefficient is most sensitive to Reiner-Philippoff fluid parameter.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105884"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimization of a cylindrical heatsink with L-shaped fins to minimize thermal resistance variation by installation angle

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-20 DOI: 10.1016/j.csite.2025.105860

Gihyun Song, Hak-Ho Nam, Seungmin Heo, Se-Jin Yook

{"title":"Optimization of a cylindrical heatsink with L-shaped fins to minimize thermal resistance variation by installation angle","authors":"Gihyun Song, Hak-Ho Nam, Seungmin Heo, Se-Jin Yook","doi":"10.1016/j.csite.2025.105860","DOIUrl":"10.1016/j.csite.2025.105860","url":null,"abstract":"<div><div>Light Emitting Diode (LED) lighting can be installed at various angles depending on user preferences. However, the cooling performance of heatsinks may decrease with changes in installation angle, potentially affecting the lifespan of LED lighting. This study considered L-shaped fins on a cylindrical base in an effort to minimize variations in thermal resistance with changes in installation angle while reducing the heatsink mass. Thermal resistance was analyzed based on the area removed from rectangular fins to form L-shaped fins. The heatsink's thermal resistance was predicted across a range of installation angles through numerical analysis using ANSYS FLUENT, and the accuracy of these predictions was validated experimentally. By varying the fin deletion area, fin count, and cylindrical base radius, the ranges of porosity factor and finning factor were determined as 0.7054 ≤ <em>φ</em> ≤ 0.7494 and 2.1069 ≤ <em>ψ</em> ≤ 3.9874, respectively. With the heatsink installation angle varying from 0° to 180°, the rate of change in thermal resistance for a cylindrical heatsink with rectangular fins (without a deletion area) was large, reaching 24 %, while that for a cylindrical heatsink with L-shaped fins was significantly reduced, staying within 10 %. A correlation equation to estimate the thermal resistance of an L-finned cylindrical heatsink was proposed, predicting thermal resistance with an error margin of up to 15 %. The cylindrical heatsink with L-shaped fins developed in this study is expected to be applicable in various LED lighting systems requiring both reduced heatsink mass and minimal thermal resistance variation with changes in installation angle.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105860"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An experimental study on the effect of lobe swirl device and its transition parts on thermal performance using Graphene-CuO/water nanohybrid

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105925

Farag A. Diabis , Abd Rahim Abu Talib , Norkhairunnisa Mazlan , Eris Elianddy Supeni

{"title":"An experimental study on the effect of lobe swirl device and its transition parts on thermal performance using Graphene-CuO/water nanohybrid","authors":"Farag A. Diabis , Abd Rahim Abu Talib , Norkhairunnisa Mazlan , Eris Elianddy Supeni","doi":"10.1016/j.csite.2025.105925","DOIUrl":"10.1016/j.csite.2025.105925","url":null,"abstract":"<div><div>Enhancing heat transfer efficiency is a key focus in thermal applications. Smooth channels often suffer from poor fluid mixing, limiting their performance. Swirl flow techniques have been introduced to improve heat exchanger efficiency by altering flow direction and inducing turbulence. However, integrating nanofluids with swirl techniques presents challenges such as increased pressure loss and nanoparticle sedimentation. The four-lobed swirl generator is a promising solution, delivering high swirl intensity with manageable pressure loss. This study explores the impact of GO-CuO/water hybrid nanofluid and Reynolds numbers on the thermal performance of a four-lobed swirl generator. The system parameters include a twisted angle (θ = 360°), β-transition type, transition multiplier (n = 0.5 mm), and a variable helix (t = 1). The hybrid nanofluid, synthesized with a 20 % GO to 80 % CuO ratio, has volume concentrations of 0.15%–0.75 % wt., with Reynolds numbers from 15,000 to 35,000. Results indicate a significant heat transfer enhancement (1.26–1.72 times) with a moderate friction factor increase (1.27–1.53). The highest thermal performance (1.511) occurs at 0.75 % nanofluid concentration and <em>Re</em> = 25,000. This study confirms the four-lobed swirl generator's effectiveness in improving heat exchanger efficiency while maintaining an acceptable pressure drop.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105925"},"PeriodicalIF":6.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of nitrogen contents in fuel and oxidizer on nitrogen oxide emissions during NG/O2 combustion

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105868

Wontak Choi , Seunggi Choi , Yonmo Sung

{"title":"Influence of nitrogen contents in fuel and oxidizer on nitrogen oxide emissions during NG/O2 combustion","authors":"Wontak Choi , Seunggi Choi , Yonmo Sung","doi":"10.1016/j.csite.2025.105868","DOIUrl":"10.1016/j.csite.2025.105868","url":null,"abstract":"<div><div>This study aims to understand the NO<sub>x</sub> emission characteristics during pure oxygen (O<sub>2</sub>) combustion of natural gas (NG) and to provide design data for application in forging furnaces. We numerically investigated the sensitivity of NO<sub>x</sub> emissions to an up to 10 % increase in nitrogen (N<sub>2</sub>) content of the fuel and oxidizer. According to the impact analysis, the two cases have a more adverse effect on NO<sub>x</sub> emissions. The numerical model established in this study was verified using experimental results obtained by the International Flame Research Foundation (IFRF). In addition, the N<sub>2</sub> content of the fuel was fixed and the impact of NO<sub>x</sub> emissions on the O<sub>2</sub> ratio (O<sub>2</sub>/fuel equivalence ratio) was investigated. The calculated results for the temperature field, velocity field, and NOx concentration at the furnace outlet agree with the IFRF experimental results. As the N<sub>2</sub> content in the oxidizer and fuel increased, the NO<sub>x</sub> concentration also increased. NO<sub>x</sub> emissions were much higher with a larger amount of N<sub>2</sub> in the fuel than in the oxidizer. With fixed N<sub>2</sub> content in the fuel, NO<sub>x</sub> concentration tended to increase as the O<sub>2</sub> ratio increased. As the N<sub>2</sub> content in the fuel increased, the tendency of the NO<sub>x</sub> concentration to increase with the O<sub>2</sub> ratio became more evident. This study emphasizes the importance of minimizing the N<sub>2</sub> content in both the fuel and oxidizer during NG-O<sub>2</sub> combustion, and suggests that NO<sub>x</sub> emissions can be effectively controlled by adjusting the oxygen ratio when N<sub>2</sub> is present.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105868"},"PeriodicalIF":6.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Low-temperature combustion analysis of butanol isomer/diesel blends under reduced oxygen conditions in a constant volume combustion chamber

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105929

Jinlin Han , L.M.T. Somers

{"title":"Low-temperature combustion analysis of butanol isomer/diesel blends under reduced oxygen conditions in a constant volume combustion chamber","authors":"Jinlin Han , L.M.T. Somers","doi":"10.1016/j.csite.2025.105929","DOIUrl":"10.1016/j.csite.2025.105929","url":null,"abstract":"<div><div>Butanol is an attractive biofuel and power resource in the field of power generation, long-haul heavy-duty transportation, and off-road applications. Particularly, when combined with low temperature combustion concepts, the NOx/soot tradeoff can be relieved at the presence of exhaust gas recirculation. Therefore, the combustion and ignition characteristics of butanol isomers at low oxygen (O2) availability should be fully understood. This work focuses on the low temperature heat release and negative temperature coefficient behaviors at low O2% in a CVCC. Three butanol isomers are blended with diesel from 20 to 80 vol% and tested at various temperatures and oxygen concentrations (17 %, 15 %, 13 %). Tert-butanol/diesel blends yield the shortest ignition delay (ID) time. This is likely due to the competition of the OH radical between the butanol and alkane. The results also show ID increases as the blend ratio increases. Specifically, at a low blend ratio, the ignition delay will increase as the oxygen concentration and chamber temperature decrease. As the blend ratio reaches 60 and 80 vol %, ID decreases at low chamber temperature irrespective of the O2%, due to early low temperature heat release. A similar transition trend can be found in the burn duration results as well.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105929"},"PeriodicalIF":6.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Exploration of physical characteristics of gyrotactic microorganisms and Cattaneo-Christov heat flux past a cone and a wedge with thermal radiation

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105916

G. Dharmaiah , K.S. Balamurugan , H. Saxena , U. Fernandez-Gamiz , S. Noeiaghdam , Maddina Dinesh Kumar , C.S.K. Raju

引用次数: 0