Case Studies in Thermal Engineering最新文献

{"title":"Paradigm predictive analysis of two-phase Eyring–Powell fluid flow over a vertical stretching sheet with temperature-dependent viscosity by multilayer neural networks","authors":"Zahoor Shah, Hamza Iqbal, Waqar Azeem Khan, Taseer Muhammad, Muhammad Shoaib","doi":"10.1016/j.csite.2025.106289","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106289","url":null,"abstract":"Recently, the accuracy and efficiency of solving complex fluid problems have benefited greatly from these latest advances in AI-integrated fluid mechanics. Deep-learning neural networks optimized with the Levenberg-Marquardt algorithm (DLNNs-LMA) is a supervised AI-based approach that is used to analyze the Eyring Powell fluid in a two-phase flow (EPFM-TPF) with dust particles and at temperature-dependent viscosity. PDEs are converted into nonlinear ODEs with similarity transformations, which are solved using the Adam method in Mathematica with varied physical parameters to generate a reference dataset. Finally, we examine graphically velocity and temperature profiles of both fluid and dust particles and for significant parameters. The novel DLNNs-LMA were used for the numerical computations on the reference data. The error analysis indicates a close correlation with the proposed databases and with reference datasets, having values between 10<ce:sup loc=\"post\">-3</ce:sup> and 10<ce:sup loc=\"post\">-9</ce:sup>, which indicates a high accuracy of the proposed methodology. Its consistently low MSE (mean square error) values (at the scale of E-09 to E-10) make it a good approximation for most scenarios; there is very little deviation and strong predictability. The results obtained validate the robustness of the DLNNs-LMA approach to solve complex fluid dynamics problems. Further, there is variation in epochs (from 54 to 585) to account for the adaptability of the model, leading to the best convergence despite differences in scenarios. It is observed that the velocity profile gradually increases with the rising trend of <ce:italic>M</ce:italic> and <ce:italic>β</ce:italic>, and the absolute error was found in the range between E-04 to E-07 and E-02 to E-07, respectively.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"14 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184231","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":"Experimentally validated transient enthalpy-based FEM model for PCM-integrated building materials with advanced thermal and energy efficiency insights","authors":"Ajitanshu Vedrtnam, Kishor Kalauni, Nelson Soares","doi":"10.1016/j.csite.2025.106374","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106374","url":null,"abstract":"This study presents a high-fidelity finite element method (FEM) framework for modelling the thermal performance of phase change material (PCM)-integrated building materials, validated against experimental data. The model accurately captures transient thermal dynamics, including latent heat storage and release, subcooling effects, natural convection, and the influence of embedded aluminum fins. Through extensive parametric analysis, the model reveals critical insights into temperature profiles, phase boundary evolution, entropy generation, and energy efficiency across different material depths. Compared to experimental observations, the FEM predictions exhibit strong correlation, offering deeper understanding of PCM behaviour under dynamic conditions. Additionally, thermal response time maps and solid fraction distributions provide novel performance metrics not captured in conventional experimental studies. The framework's adaptability across different PCM formulations and building configurations underscores its utility as a robust design tool for optimizing PCM placement, layer thickness, and thermal management strategies in energy-efficient buildings.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"8 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184215","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":"Significance of Brownian diffusion and thermophoresis in energy and mass optimization for Newtonian and Non-Newtonian fluid flow: A numerical study via Keller-Box method","authors":"Khursheed Muhammad, Mahnoor Sarfraz, Haifaa F. Alrihieli, Ibrahim E. Elseesy","doi":"10.1016/j.csite.2025.106365","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106365","url":null,"abstract":"This article presents a comparative study of the Jeffrey fluid and Newtonian fluid flow over an electrically conducting sheet undergoing thermo-diffusion and Brownian diffusion. Temperature gradients and random motion of particles drive thermo-diffusion and Brownian diffusion. At the same time, the flow is induced by the Hall effect and thermal radiation. The sheet stretches along the <ce:italic>x</ce:italic>-axis and remains stationary along the <ce:italic>y</ce:italic>-axis. The research employs the modified Fourier law, known as the Cattaneo-Christov heat flux, to model thermal and solutal distribution. Numerical solutions are obtained using the Keller-Box method in MATLAB. After modeling the physical problem, suitable transformations are implemented to obtain non-linear boundary value problem in term of ODEs. These non-linear ODEs with BCs are tackled by the Keller-Box method (an implicit finite difference scheme) for solution. The Keller-Box method is faster, efficient and more flexible for non-linear problems. This method has second order accuracy and unconditional stability. The study comprehensively examines the resulting flow, thermal, and mass characteristics. It is seen that higher thermal and solutal relaxation time parameters moderate heat and mass transfer, resulting in lower temperature and concentration. These results reflected the viscoelastic nature of Jeffrey fluid and its distinct response to magnetic influences. The findings provide valuable insight into the effects of non-Newtonian and Newtonian fluid properties with potential applications in engineering and industrial processes. This study contributes original insights by integrating the Cattaneo-Christov heat flux and Buongiorno's model. The emphasis is on the comparative analysis of non-Newtonian and Newtonian fluid with control parameters on physical quantities provides a novelty.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"33 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184216","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":"Enhancing heat dissipation and temperature uniformity of microchannel heat sinks using fractal gradient honeycomb-reverse Tesla valve configuration","authors":"Chun-Yu Chen, Min Yang, Yuanyuan Li, Gui Lu","doi":"10.1016/j.csite.2025.106371","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106371","url":null,"abstract":"This study introduces a fractal gradient honeycomb-reverse Tesla valve configuration (HC-RTV-GD) to enhance heat transfer and temperature uniformity in high-flux thermal management systems. Through comparative analysis with conventional Tesla valves and honeycomb structures, the HC-RTV-GD leverages hierarchical bifurcation and controlled turbulence generation to achieve superior heat transfer performance. At high Reynolds numbers, the design significantly reduces thermal resistance and suppresses maximum wall temperatures while flattening longitudinal temperature gradients, mitigating thermal stress risks. The improved temperature uniformity stems from gradient-driven flow redistribution, which minimizes stagnant zones and sustains coolant velocity in secondary channels. Thermal improvements come with hydraulic trade-offs: the gradient geometry amplifies flow resistance through localized vortices, elevating pressure drop and friction coefficients compared to conventional designs. Performance evaluation confirms the HC-RTV-GD’s viability exclusively in high-flux scenarios, where heat transfer gains outweigh pumping penalties. A neural network-enhanced optimization framework further identifies optimal coolant parameters, balancing thermal and hydraulic efficiency. The HC-RTV-GD advances cooling system design by strategically combining geometric complexity with turbulence control, prioritizing thermal uniformity in extreme heat flux environments.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"33 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130777","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":"Thermo-physical properties evaluation of commercially available phase change material and engine oil","authors":"Prabhakar Bhandari, Nitish Yadav, Diwakar Padalia, Lalit Ranakoti, Tabish Alam, Md Irfanul Haque Siddiqui, Intesaaf Ashraf","doi":"10.1016/j.csite.2025.106357","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106357","url":null,"abstract":"Phase Change Materials (PCMs) efficiently store and release latent heat during phase transitions, with Solid-Liquid PCMs being widely used in industries such as renewable energy and battery thermal management due to their ability to maintain a nearly constant temperature. However, challenges like low density, low thermal conductivity, and high viscosity necessitate customized solutions for specific applications. To address this, different Composites Phase Change Materials (CPCM) were prepared. To fabricate these materials commercially available PCMs and pure engine oil were used. Two different PCM samples (OM50 and OM42) were used. Ultrasonication method was used to make homogenised samples. The molecular structure was studied using Fourier Transform Infrared (FTIR) spectroscopy. Thermal analysis (TGA and DSC) indicate that the thermal behaviour of the samples change with the filling level of PCM in engine oil. TGA plots confirm the expected phase-change behavior, and composites with engine oil exhibit greater thermal stability by reducing mass loss at 300 °C. Reduction in melting point in the samples was observed due to reduction in intermolecular forces. Density measurements indicate that mixing does alter inter-moleculer interactions, the decomposition onset temperature remains unchanged, preserving the operational temperature range, while the blend with 40 % engine oil shows the lowest density, suggesting maximum dissolution of the organic PCM. Thermal conductivity in OM 50 varies by 25.3 %, while in OM 42 it changes by 16.5 % with increasing engine oil concentration. These results highlight the potential of high-performance organic PCM and engine oil composites for efficient and cost-effective energy storage systems.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"11 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184217","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 on the detonation characteristics of reverse-flow pulse detonation combustors via blockage ratio","authors":"Yudong Yang ,&nbsp;Longxi Zheng ,&nbsp;Dingding Wang ,&nbsp;Changxin Peng ,&nbsp;Jie Lu","doi":"10.1016/j.csite.2025.106366","DOIUrl":"10.1016/j.csite.2025.106366","url":null,"abstract":"<div><div>The reverse-flow pulse detonation combustor (PDC) exhibits a shorter axial length in contrast to the straight-tube PDC, thereby enhancing its suitability for engineering applications. In order to investigate the influence of the blockage ratio of the mixing section on the detonation characteristics of the reverse-flow PDC, a combined approach of numerical calculation and experiment was adopted. The detonation characteristics of the PDC under different blockage ratio schemes were comparatively analyzed. The results show that elevating the blockage ratio can effectively reduce the size of the reverse-flow zone, eliminate the oil entrainment phenomenon. The deflagration to detonation (DDT) distance generally first increases and then decreases as the blockage ratio rises. In contrast to the baseline scenario, for the PDC structure with a blockage ratio of 0.65, the lean flameout limit has a minimum reduction of 35 % (at 5 Hz) and a maximum reduction of 59 % (at 25 Hz). The rich flameout limit has a minimum reduction of 2 % (at 5 Hz) and a maximum reduction of 39 % (at 20 Hz). The stable working range is enhanced by a minimum of 1.12 times (at 10 Hz) and a maximum of 2.55 times (at 15 Hz).</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"72 ","pages":"Article 106366"},"PeriodicalIF":6.4,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099477","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 thermochromic materials parameters to improve energy efficiency in hot summer and cold winter regions","authors":"Chenxi Hu, Hiroatsu Fukuda, Fudan Liu, Yanna Gao","doi":"10.1016/j.csite.2025.106354","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106354","url":null,"abstract":"Solar radiant heat gain reduces air conditioning energy consumption and improves the thermal environment in winter, but the opposite is true in summer. Conventional building skin materials, with constant solar reflectance, fail to address the varying heat demands between seasons. This study investigates thermochromic materials (TCMs), which dynamically adjust their color and solar reflectance in response to environmental changes, thereby optimizing energy efficiency in hot-summer and cold-winter regions. Two key parameters of TCMs—discoloration temperature and reflectance range—are analyzed for their impact on energy savings. Results show that a coating with a discoloration temperature of 37.7 °C and a reflectance range of 60 %–90 % achieves the highest 10.76 % energy savings. Additionally, a life cycle economic evaluation reveals that TCMs are more cost-effective than other energy-saving materials, with an average annual cost as low as 0.53 RMB/m<ce:sup loc=\"post\">2</ce:sup>-y.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"33 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130779","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 analysis of flow heat transfer characteristics and optimization of double-layered microchannel heat sinks with different structures","authors":"Bo Cai, Pan Hu, Yifan Li, Bingzhi Chen, Haoyang Cai","doi":"10.1016/j.csite.2025.106370","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106370","url":null,"abstract":"This paper proposes a novel double-layered microchannel heat sink (TMC-ORTC), specifically, the upper layer consisted of a truncated rectangular microchannel, while the lower layer features a microchannel that combines trapezoidal cavity with oval rib. The flow and heat transfer characteristics of 8 distinct configurations of double-layer microchannel heat sinks (DL-MCHSs) are investigated through numerical simulations at Reynolds numbers (<ce:italic>Re</ce:italic>) ranging from 150 to 950. Various performance parameters, including pressure drop, friction coefficient, thermal resistance, average Nusselt number (<ce:italic>Nu</ce:italic>), temperature uniformity, entropy production and heat transfer enhancement factor, are analyzed respectively. The structural parameters of TMC-ORTC are optimized by multi-objective genetic algorithm with thermal resistance, pumping power and temperature uniformity as optimization objectives. The results indicate that the combination of cavity and rib microchannel leverages the benefits of ribs to enhance fluid disturbance and heat transfer, while cavities serve to increase the flow area within the microchannel and reduce pressure drop. Among all the DL-MCHSs studied in this paper, compared with the single arrangement of cavity or rib structure within the microchannel, the combination of cavity and rib structure results in a more pronounced enhancement of the flow and heat transfer performance of the DL-MCHS. The TMC-ORTC outperforms other microchannel heat sinks (MCHSs) in comprehensive performance. When Re = 895.69, compared with the traditional double-layered rectangular microchannel heat sinks (MC-MC), the average Nusselt number of TMC-ORTC has increased by 121.67 %, the temperature uniformity is increased by 81.7 %, the maximum heat transfer enhancement factor is 1.899, the minimum value of augmentation entropy generation number (<ce:italic>N</ce:italic><ce:inf loc=\"post\">s,a</ce:inf>) is 0.89. The optimization results show that when the width of oval rib (<ce:italic>W</ce:italic><ce:inf loc=\"post\">r</ce:inf>) is 0.056 mm and the truncated length of the upper microchannel (<ce:italic>L</ce:italic><ce:inf loc=\"post\">x</ce:inf>) is 1.494 mm, the comprehensive performance of TMC-ORTC is the best.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"22 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130778","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 hybrid nanofluids on entropy dynamics and transient thermal behavior in a finned enclosure with cylindrical obstruction","authors":"Chunyang Li, Hassan Roshani, Mohammad Jalili, Mohamed H. Mohamed, Payam Jalili, Bahram Jalili, Irshad Ahmad, Qasem M. Al-Mdallal","doi":"10.1016/j.csite.2025.106339","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106339","url":null,"abstract":"The purpose of this research was to the flow behavior, heat transfer rate, and entropy generation by the hybrid nanofluid flow (Al<ce:inf loc=\"post\">2</ce:inf>O<ce:inf loc=\"post\">3</ce:inf>+Cu + H<ce:inf loc=\"post\">2</ce:inf>O) inside a square finned cavity containing a cylindrical barrier in its upper half in a time interval of <mml:math altimg=\"si1.svg\"><mml:mrow><mml:mn>20</mml:mn></mml:mrow></mml:math> seconds. Al<ce:inf loc=\"post\">2</ce:inf>O<ce:inf loc=\"post\">3</ce:inf> and Cu nanoparticles have concentrations of 5 % and 3 %, respectively, and water is chosen as the base fluid. In this research, Reynolds and Richardson numbers represent inertial and buoyant forces. In the square cavity geometry, two fins with a length of 0.3 and a width of 0.1 are embedded in the vertical walls, and the four corners of the cavity have 90° sectors. The entropy generation is also investigated using the derived profiles, and the heat transfer rate is computed using the average and local Nusselt numbers. The hybrid nanofluid flow's governing equations were resolved by applying the Galerkin finite element method. The findings showed that as the Richardson number in each of the Reynolds numbers rose, so did the hybrid nanofluid's horizontal and vertical velocities during the designated period and that the temperature distribution from the lower surface to the top half of the cavity expanded.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"6 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184187","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":"Waste heat harness in a thermal energy system using TEGs, and SCO2 brayton cycle driven by renewable sources for electricity and liquid hydrogen Production: Thermo-Economic optimization using ANNs","authors":"Amr S. Abouzied, Sarminah Samad, Pradeep Kumar Singh, Ahmed H. Janabi, Mohamed Shaban, Asma Ahmed A. Mohammed, Shoira Formanova, H. Elhosiny Ali, Samah G. Babiker, Abdulrahman M. Alansari","doi":"10.1016/j.csite.2025.106369","DOIUrl":"https://doi.org/10.1016/j.csite.2025.106369","url":null,"abstract":"This research introduces an innovative thermal energy system that combines solar and wind energy to produce electricity, generate hydrogen, and facilitate liquefaction. This system includes a parabolic trough solar collector (PTSC) that heats nitrate salts, transferring the thermal energy to a supercritical carbon dioxide Brayton cycle (SCO<ce:inf loc=\"post\">2</ce:inf>-BC). Furthermore, thermoelectric generators (TEG) are integrated to capture energy from waste heat sources. Additionally, this study breaks new ground by incorporating solar and wind power with a supercritical CO<ce:inf loc=\"post\">2</ce:inf> cycle alongside hydrogen liquefaction, a field that is still relatively uncharted. A detailed techno-economic and environmental model is utilized to assess the system's performance, concentrating on critical indicators such as second law efficiency, total cost rate, hydrogen production rate, net power output, levelized costs, and the rate of CO<ce:inf loc=\"post\">2</ce:inf> emission reduction. Following this, an optimization process is carried out using a genetic algorithm to investigate two different scenarios. Finally, the LINMAP method is applied to identify optimal solutions for each scenario. The study reveals that the system generated a grid power output of 461.2 kW and produced 8.3 kg of liquid hydrogen per hour. The overall cost of operation was established at 103.8 $/h with an exergy efficiency of 16.2 %. Further refinements resulted in values of 19.33 % for second-law efficiency, 124.80 $/h for cost rate, and 1021.64 kW for grid power.","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"204 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184219","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}