Case Studies in Thermal Engineering最新文献

{"title":"Conjugate heat transfer in wedged latticework cooling ducts with ejection flow for turbine blades","authors":"Binye Yu, Xingwei Li, Jie Li, Shi Bu","doi":"10.1016/j.csite.2024.105621","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105621","url":null,"abstract":"Trailing edge of high temperature turbine blades faces challenge of severe thermal environment due to wedged profile and hence limited cooling spaces. Latticework is a competitive cooling scheme which provides superior structural strength and heat transfer enhancement level, thereby having potential to be used for trailing edge cooling. Besides, conjugate heat transfer characteristics within wedged latticework ducts must be clarified to achieve advanced design. This work fills the gap between geometric complexity and simultaneous consideration of convective-conductive heat transfer. Influence factors including ejection flow configuration, wedge angle and ejection hole dimensions are investigated in sequence in terms of cooling efficiency, temperature distribution, thermo-hydrodynamic performance, relative temperature deviation and thermal-mechanical behavior. The result indicates that heat transfer can be improved by 80 % via optimizing ejection flow configuration. Increasing wedge angle helps enhance heat transfer under the effect of lateral ejection. Expanding ejection hole dimension by varying aspect ratio leads to better thermo-hydrodynamic performance. Besides, structure thermal stress shows a consistent trend with the relative temperature deviation. These findings highlight the role of conjugate heat transfer in trailing edge cooling, also provide guidelines for designing of similar micro-channel heat exchangers where both thermal capability and uniformity are of great importance.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"48 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858330","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":"Effects of position of semi-circular body on melting of a novel B4C/RT44HC PCM nanocomposite in a closed space","authors":"Ezgi Gurgenc, Muhammed Gur, Hakan Cosanay, Turan Gurgenc, Hakan F. Oztop","doi":"10.1016/j.csite.2024.105628","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105628","url":null,"abstract":"This study focuses on optimizing the thermal performance of a novel Boron Carbide (B<ce:inf loc=\"post\">4</ce:inf>C) enhanced RT44HC phase change material (PCM) nanocomposite by analyzing the effects of different semi-circular partition placements within a closed cavity. The primary objective is to determine how the position of these adiabatic bodies influences the melting behavior, thermal conductivity, and energy storage capacity of the PCM. Through detailed computational modeling using the finite volume method and experimental validation, the research reveals that incorporating B<ce:inf loc=\"post\">4</ce:inf>C nanoparticles significantly improves thermal performance, achieving up to a 69.65 % increase in thermal conductivity and a 19.68 % enhancement in energy storage capacity compared to pure PCM. The findings contribute to the field of advanced thermal energy storage and management by presenting a robust strategy for optimizing heat transfer in PCM systems, with potential applications in sustainable building design, electronic cooling, and energy-efficient technologies.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"24 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858329","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":"Research on digital twin modeling method for combustion process based on model reduction","authors":"Yue Zhang, Jiale Li","doi":"10.1016/j.csite.2024.105619","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105619","url":null,"abstract":"In response to the difficulty in obtaining combustion information within coal-fired boiler furnaces, a method is proposed in this study to improve the reduced-order model using clustering segmentation. This approach aims to rapidly predict the combustion temperature field inside the furnace by establishing a twin model of the combustion temperature field. Initially, the finite volume method is employed to analyze the combustion system of a 600 MW subcritical boiler under various operating conditions. Subsequently, cross-sectional data from burner nozzle positions at each operating condition are extracted. These data are subjected to Proper Orthogonal Decomposition (POD), Spectral Proper Orthogonal Decomposition (SPOD), and Wavelet Transform-POD (WT-POD) for dimensionality reduction to obtain modal data. Comparative analyses are conducted on the modal data obtained from different methods. Furthermore, based on modal data analysis, a Support Vector Machine (SVM) regression model is selected to reconstruct the temperature field. The average absolute error of the reconstructed temperature fields from three methods under different operating conditions is then compared. Finally, the model is refined using clustering segmentation, resulting in an improvement of approximately 0.6 % in reconstruction accuracy. This enhancement demonstrates that the clustered POD-SVR-GA model achieves higher accuracy in reconstructing combustion temperature fields after clustering-based improvements.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"22 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858331","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":"Evaluation of machine learning models for predicting performance metrics of aero-engine combustors","authors":"Huan Yang, Shu Guo, Haolin Xie, Jian Wen, Jiarui Wang","doi":"10.1016/j.csite.2024.105627","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105627","url":null,"abstract":"As environmental standards tighten and aero-engine performance improves, credible mapping between structural parameters and performance metrics is crucial for optimizing combustion chamber design. A new consolidated dataset with 46 various geometric structures for lean premixed prevaporized combustors is established based on the numerical simulation. The prediction performance of six machine learning models is evaluated for key combustor metrics, including the overall temperature distribution factor (OTDF), radial temperature distribution factor (RTDF), total pressure loss (Δ<ce:italic>P</ce:italic>), and cooling effect evaluation index (<ce:italic>R</ce:italic><ce:inf loc=\"post\">t</ce:inf>). The Extra Tree model exhibits superior predictive accuracy for various combustor performance metrics. It achieves the mean absolute percentage error values of 5.70 % and 6.33 % for OTDF and RTDF, respectively. For total pressure loss Δ<ce:italic>P</ce:italic>, the Extra Tree demonstrates a mean absolute percentage error of 1.62 % and an R-Square value of 0.9971. For the cooling effect evaluation index <ce:italic>R</ce:italic><ce:inf loc=\"post\">t</ce:inf>, the Extra Tree achieves a mean absolute percentage error of 14.07 %. The Support Vector Machine model is not recommended for predicting combustor performance metrics. Feature importance analysis indicates that the cooling hole diameter and the third-stage swirler angle significantly impact combustor performance. The findings highlight the promise of machine learning in optimizing combustor design and improving the reliability of the aero-engine.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"30 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858337","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":"Optimization of heat transfer in heat pipes using nanofluids at various inclinations and filling levels","authors":"Prabhu Alphonse, Karthikeyan Muthukumarasamy, Sivakumar Elumalai, Manikandan Kadamban, Ratchagaraja Dhairiyasamy","doi":"10.1016/j.csite.2024.105624","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105624","url":null,"abstract":"This study investigates the thermal performance of heat pipes filled with various nanofluids under different operational conditions, including inclination angles, filling ratios, and heat inputs. The objective was to evaluate the impact of silver (Ag), aluminum oxide (Al₂O₃), and multi-walled carbon nanotube (MWCNT) nanofluids on thermal resistance and heat transfer coefficients. Experiments were conducted using a heat pipe with a 750 mm length divided into evaporator, adiabatic, and condenser sections. Nanofluids were tested at filling ratios of 60 %, 70 %, 80 %, and 90 %, and inclination angles of 0°, 45°, 60°, and 90°. The results show that MWCNT nanofluid exhibits the lowest thermal resistance, decreasing from 1.23 K/W at 0° to 0.61 K/W at 90°, outperforming other fluids. The overall heat transfer coefficient of MWCNT increased to 4900 W/m<ce:sup loc=\"post\">2</ce:sup>K at a 90 % filling ratio and 90° inclination. The study concludes that MWCNT nanofluids provide the highest thermal efficiency, particularly at steeper inclinations and higher filling ratios, making them ideal for high-performance thermal management applications.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"21 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815800","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":"Advanced finite element modeling for dual simulations of Carreau-Yasuda fluid subjected to thermal jump using three-dimensional stretching and shrinking surfaces","authors":"M. Adil Sadiq, Haitham M.S. Bahaidarah, H. Khan, A.A. Altawallbeh","doi":"10.1016/j.csite.2024.105617","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105617","url":null,"abstract":"The current problem consists of dual solutions of Carreau Yasuda fluid in flow, mass diffusion and heat energy on 3D expanding and shrinking surfaces. The suspension of tri-hybrid nano-fluid named <mml:math altimg=\"si1.svg\"><mml:mrow><mml:mi>T</mml:mi><mml:mi>i</mml:mi><mml:msub><mml:mi>O</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mo>,</mml:mo><mml:mi>S</mml:mi><mml:mi>i</mml:mi><mml:msub><mml:mi>O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>, ethylene glycol and aluminum oxide are observed. Heat energy and mass diffusion equations consist of influences of Soret, Dufour, viscous dissipation and heat sink. Tri-hybrid nanofluids have various utilizations in industrial plastics, surgical implants, optical filters, microsensors of biological applications and electronic processes. The variable fluidic properties (thermal conductivity and mass diffusion) have been utilized. The variable magnetic field is observed. Galerkin finite element method with linear shape functions and Galerkin approximations is used to numerically solve normalized conservation equations. Analyses of mesh independence and convergence are performed to guarantee the accuracy of the solutions. The reliability of the findings is confirmed by comparing them to benchmark data. A complicated model in terms of Odes is numerically resolved by finite element methodology which is better given accuracy and convergence. Similarity transformations have been utilized for obtaining Ode’s through PDEs while numerical simulations are achieved through the finite element method. It was experienced that the temperature profile declined with the Dufour number and magnetic number. The opposite trend is experienced in mass diffusion when the Soret number and Schmidt number are enhanced.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"146 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815802","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 study of optimal control approaches of water-to-water CO2 heat pump for domestic hot water use","authors":"Yantong Li, Natasa Nord, Huibin Yin, Gechuanqi Pan, Changhong Wang, Tingting Wu, Inge Håvard Rekstad","doi":"10.1016/j.csite.2024.105615","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105615","url":null,"abstract":"Carbon dioxide (CO<ce:inf loc=\"post\">2</ce:inf>) heat pumps are not causing ozone layer depletion, while offering high temperature water. Typical control (TC) can realize normal operation of water-to-water CO<ce:inf loc=\"post\">2</ce:inf> heat pump. However, the approach for developing model-based optimal control (MC) for further improving the performance of water-to-water CO<ce:inf loc=\"post\">2</ce:inf> heat pump is still lacking. Hence, this study presents MC approaches for water-to-water CO<ce:inf loc=\"post\">2</ce:inf> heat pump. The developed model-based controller was composed of the optimization strategy and system models. The objective of optimization strategy was to maximize system coefficient of performance by identifying optimal setpoint values of discharge pressure and outlet water temperature at the gas cooler side. System models of compressor power and heat rate at the gas cooler side were established using large amount of data from virtual CO<ce:inf loc=\"post\">2</ce:inf> heat pump. The reliability of virtual CO<ce:inf loc=\"post\">2</ce:inf> heat pump was validated by experimental data. Results of case studies demonstrated that the system coefficient of performance with MC could be improved by 7.8 %–14.6 % in comparison with that with TC. This study therefore gave a guideline for optimal control of water-to-water CO<ce:inf loc=\"post\">2</ce:inf> heat pump.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"201 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858332","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":"Computational study and optimization of an inclined U-channel cooling system for triple conductive panels under magnetic field","authors":"Fatih Selimefendigil, Hakan F. Oztop","doi":"10.1016/j.csite.2024.105532","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105532","url":null,"abstract":"In order to maximize the efficacy of multiple component electronic systems or photovoltaic panels in multiple arrangements, thermal management and cooling system design become crucial. In the present work, a novel cooling system with U-shaped cooling channel for a triple conductive panel system is considered under ternary nano-enhanced magnetic field effects while Galerkin weighed residual finite element method is used as the solution technique. The numerical investigation is carried out for various Hartmann numbers (Ha between 0 and 60), magnetic field inclination (between 0 and 90), side wall inclination of cooling cavity (between 0 and 30), and cavity expansion ratio (between 0.2 and 0.5). At the highest Ha value, panel Pn2 shows a temperature reduction of 52 °C for <mml:math altimg=\"si1.svg\" display=\"inline\"><mml:mrow><mml:mi>η</mml:mi><mml:mo linebreak=\"goodbreak\" linebreakstyle=\"after\">=</mml:mo><mml:mn>0</mml:mn></mml:mrow></mml:math>, and an increase of roughly 24 °C for <mml:math altimg=\"si71.svg\" display=\"inline\"><mml:mrow><mml:mi>η</mml:mi><mml:mo linebreak=\"goodbreak\" linebreakstyle=\"after\">=</mml:mo><mml:mn>30</mml:mn></mml:mrow></mml:math>. The best magnetic field inclination for the lowest surface temperature varies according to the panels and cooling channels used. The surface temperature variation is 2 °C, 114 °C, and 114 °C for panels Pn1, Pn2, and Pn3, when comparing the best and worst cases. As expansion ratios increase, the average Nu generally drops in cooling channels with both flat (<mml:math altimg=\"si1.svg\" display=\"inline\"><mml:mrow><mml:mi>η</mml:mi><mml:mo linebreak=\"goodbreak\" linebreakstyle=\"after\">=</mml:mo><mml:mn>0</mml:mn></mml:mrow></mml:math>) and inclined (<mml:math altimg=\"si71.svg\" display=\"inline\"><mml:mrow><mml:mi>η</mml:mi><mml:mo linebreak=\"goodbreak\" linebreakstyle=\"after\">=</mml:mo><mml:mn>30</mml:mn></mml:mrow></mml:math>) walls. Based on the first three objectives by using optimization with COBYLA, panels Pn1, Pn2, and Pn3 have minimum temperatures of 30.3 °C, 46.6 °C, and 41.4 °C, respectively. By utilizing different objectives, different panel surface temperatures and performance improvements are achieved.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"91 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815807","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":"Optimal configuration of a solar-powered Organic Rankine Cycle power plant utilizing thermochemical energy storage","authors":"Sofiene Mellouli, Talal Alqahtani, Salem Algarni, Abdullah A. Faqihi, Badr M. Alshammari, Lioua Kolsi","doi":"10.1016/j.csite.2024.105632","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105632","url":null,"abstract":"The thermal energy storage system greatly influences the efficiency and design of the Organic Rankine Cycle (ORC) power plant. In this research, a novel thermochemical energy storage (TCES) system was incorporated into the solar energy-driven ORC system to enhance its overall efficiency. The study details the TCES system, which utilizes paired metal hydrides (specifically LaNi<ce:inf loc=\"post\">4.25</ce:inf>Al<ce:inf loc=\"post\">0.75</ce:inf>/LaNi<ce:inf loc=\"post\">5</ce:inf>) in conjunction with a phase-change material (PCM). What makes this system unique is its integration with an ORC system-a novel approach not previously explored or examined. In order to evaluate and enhance the performance of the TCES system, an optimization model based on simulations was created using the SAM (System Advisor Model) software. This optimization framework is aimed at concurrently determining the best system design, taking into account factors such as solar multiple, storage duration, the levelized cost of electricity (LCOE), and the availability of solar resources at the location of the ORC plant. This study primarily focuses on achieving the best overall performance for a 50 MW ORC power plant in Tunisia. The results of this research demonstrate that the proposed ORC plant has the potential to generate an annual energy output of 244.2 GWh-e. This outcome is achieved through an optimized system design that incorporates a net conversion efficiency of 54.4 %, a solar multiple of 2.2, and a storage duration of 6.2 h. Additionally, the levelized cost of electricity (LCOE) decreases to a minimum value of 11.4 c/kWh. The study's findings emphasize the significance of integrating the TCES system into the ORC plant, driving advancements in solar energy technologies, and providing valuable insights for the development of future ORC plants.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"29 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815851","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 simulation study on temperature characteristics of double-deck suspension bridge in vehicle fires","authors":"Bobo Shi, Ke Jia, Shaokun Ge, Changlin He, Jun Zhao","doi":"10.1016/j.csite.2024.105626","DOIUrl":"https://doi.org/10.1016/j.csite.2024.105626","url":null,"abstract":"Knowledge of the temperature response of load-bearing structures in suspension bridges under vehicle fires is a prerequisite for fire protection measures. In this study, a double-deck suspension bridge was adopted as the engineering background. The temperature response of the main cables and slings was examined in the case of a fire on the upper vehicle deck, and the temperature characteristics of load-bearing structures such as trusses and the roof plate were investigated on the lower vehicle deck. The simulation variables included heat release rate (HRR), fire location, and ambient wind speed. The results showed that: (1) The fire temperature rose as HRR increased, and the fire temperature was inversely proportional to the wind speed. (2) When a fire occurred on the upper bridge deck, the maximum width of the high-temperature area on the main cable was 15 m, and the maximum temperature was 1040 °C. (3) When a fire occurred on the lower bridge deck, the maximum temperature of the truss was 1209 °C, and the maximum height of the high-temperature area exceeding 300 °C was 7.6 m. The maximum temperature reached in a 200 MW oil tanker fire was 1344 °C, lasting 3650 s.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"30 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815801","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}