International Journal of Thermofluids最新文献

{"title":"Jeffrey fluids heat-mass transfer analysis through porous medium by utilizing Yang-Abdel-Cattani operator","authors":"Sehra ,&nbsp;Mehwish Shafat ,&nbsp;Ilyas Khan","doi":"10.1016/j.ijft.2025.101339","DOIUrl":"10.1016/j.ijft.2025.101339","url":null,"abstract":"<div><div>Analyzing of mass and heat transfer through a permeable medium undergone exponential heat were studied in this article while using YAC (Yang-Abdel-Cattani) operator. The YAC operator performs the best to describe the generalized effects more convenient than other operator. By utilizing the appropriate set of dimensionless variable the governing equations of temperature, concentration and velocity distribution becomes non-dimensional. These non-dimensional partial differential equation are calculated by applying Laplace transformation. The effects of different fractional operators on fluids dynamics are examined. By the help of Mathcad tool, Various sketches were drawn to determine the physical actions of different parameters.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101339"},"PeriodicalIF":0.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144723562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy and exergy analysis of PCM-based pyramid solar still","authors":"Safa M. Aldarabseh ,&nbsp;Salah Abdallah","doi":"10.1016/j.ijft.2025.101349","DOIUrl":"10.1016/j.ijft.2025.101349","url":null,"abstract":"<div><div>Sustainable and effective desalination technologies are required to meet the growing demand for drinkable water worldwide. The intermittent nature of solar desalination necessitates the use of efficient thermal energy storage materials (TESMs) to prolong operation past the hours of sunshine. To improve desalination performance, this study introduces a modified stepped pyramid solar still (SSP) that incorporates phase change materials (PCMs), hollow rectangular fins, and electrical heaters driven by photovoltaic energy. In comparison to a traditional solar still, the system was tested both conceptually and experimentally in five different configurations (CSS, SSP, SSP with electrical heaters (SSE), SSP with paraffin wax and hollow rectangular fins (SSM), and SSM with electrical heaters (SSME)) during the winter, spring, and summer seasons. The findings showed that, in comparison to the CSS, the productivity, energy, and exergy efficiency of SSP in the winter and spring increased on average by 109.47 % and 204.91 %, 28.44 % and 31.68 %, and 10.21 % and 18.15 %, respectively. While the productivity, energy and exergy efficiency of SSE3 was augmented over CSS on average by 266.62 %, 45.64 %, and 23.45 %, respectively. Furthermore, the productivity energy and exergy efficiency of SSM increased over CSS on average by 431.13 %, 70.67 % and 41.5 %, respectively. SSME obtained the highest performance, with an average increase in productivity of 675.2 %, energy efficiency of 78.77 %, and exergy efficiency of 48.97 %. To simulate saline water temperature fluctuations, a thorough heat balance study was carried out, and theoretical predictions and practical observations closely matched within acceptable error range between 0.76–18. The results demonstrate how PCM-enhanced solar stills can be used for high-efficiency, sustainable water desalination, providing a workable option for areas with low access to freshwater.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101349"},"PeriodicalIF":0.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting and optimizing the wet outer surface of water-sprayed finned-tube air-cooled condensers based on purely geometric arguments for inclined sprays: Application on heat transfer enhancement for the cooling of the refrigerant R134a","authors":"Ibra Bop ,&nbsp;Biram Dieng ,&nbsp;Senghane Mbodji ,&nbsp;Gorgui Bop ,&nbsp;Ababacar Thiam","doi":"10.1016/j.ijft.2025.101347","DOIUrl":"10.1016/j.ijft.2025.101347","url":null,"abstract":"<div><div>During spray cooling, the determination of the heat energy gains due to water collection requires prior knowledge of the heater wetted surface. However, it is impossible to directly measure this surface, especially for complex geometries like finned-tube heat exchangers. In this paper, a model based on purely geometric arguments is proposed for the prediction of the wet outer surface of a water-sprayed finned-tube air-cooled condenser for an inclined spray. It is based on determining the number of wetted fins and tubes in the spray impact area and deduce therefrom the heater total wetted surface. Then, to understand the mechanism of spray cooling by examining the effects of spray inclination on heat transfers, the model is applied to the cooling of the refrigerant R134a. The results showed that the optimal horizontal spray inclination angle is 45° and increasing this angle from 0 to 45° allowed the wet surface to grow from 0.043 to 0.091 m². At <em>β</em> = 45°, the wet surface equalizes the spray impact area while the water collection rate tends to unity, which helped to intensify heat transfers from 1.718 to 1.744. Consequently, the refrigerant condensing temperature drops from 25.5 to 23.5 °C when <em>β</em> is varied from 0 to 45° and from 40 to 23.5 °C when mist is applied with 45° of inclination compared to the heater without mist. It is concluded that spray inclination allows to reduce the condenser vacuum rate and increase the water collection rate, which results in an enhancement in the condenser heat dissipation.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101347"},"PeriodicalIF":0.0,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New similarity solutions of heat and mass transfer in flow of Carreau fluid over a rough sheet with nonlinear kinematics","authors":"Muhammad Hamza ,&nbsp;Dil Nawaz khan Marwat ,&nbsp;Azhar Ali","doi":"10.1016/j.ijft.2025.101346","DOIUrl":"10.1016/j.ijft.2025.101346","url":null,"abstract":"<div><div>This research introduces novel and generalized similarity solutions for heat and mass transfer in the flow of Carreau fluid across a rough, non-flat sheet characterized by nonlinear kinematics. Previous research presented space-dependent parameters, particularly Weissenberg numbers, within the transformed ordinary differential equation systems, which is against the spirit of the fundamental principle of similarity solutions. By creating a mathematically consistent transformation, we overcome this significant issues and produce a more comprehensive and precise modelling framework. MATLAB's bvp4c approach is used to numerically solve the governing equations. Important dimensionless factors are examined in relation to velocity, temperature, concentration, and skin friction, including the Weissenberg number, non-linear kinematics, power-law index, Prandtl number, Schmidt number, and surface roughness. Notably, we discover that while raising the Weissenberg number thickens the velocity boundary layer in shear-thickening fluids, surface roughness and sheet temperature greatly increase the mass transfer rate. These findings provide new perspectives for non-Newtonian thermal processing systems, coating processes, and biomedical transport applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101346"},"PeriodicalIF":0.0,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innovative 3D numerical study of a catalyst bed and comparison with previous 2D and experimental studies","authors":"M.H. Mansuri Mughari ,&nbsp;H. Naseh ,&nbsp;S. Noori","doi":"10.1016/j.ijft.2025.101344","DOIUrl":"10.1016/j.ijft.2025.101344","url":null,"abstract":"<div><div>This paper analyzes the catalytic bed of a 10 (N) Liquid Monopropellant Thruster (LMT) in an innovative 3D numerical study. LMT includes an injector, a decomposition chamber with a catalytic bed, and a nozzle. Injectors spray Liquid propellant onto the catalytic bed (decomposition chamber). The catalyst bed decomposes the liquid propellant through thermal and chemical reactions, and the gases generated at high temperatures and pressures flow through the nozzle to create thrust force. In this thruster, liquid hydrazine is used as the monopropellant and the catalytic bed consists of iridium-coated alumina pellets (Ir/Al₂O₃) in the decomposition chamber. Catalytic and thermal reactions are modeled by calculating reaction rates using Arrhenius relationships. The results that were obtained were evaluated and compared with experimental tests and 2D numerical studies (the porous medium hypothesis and the 2D modeling of the catalyst pellets). This evaluation demonstrates the obtained results are more accurate and closely aligned with the experimental results.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101344"},"PeriodicalIF":0.0,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linear regression analysis of Williamson hybrid nanofluid flow with thermal radiation: Numerical simulation","authors":"A. Divya ,&nbsp;Gunisetty Ramasekhar ,&nbsp;Pooja M N ,&nbsp;K V Nagaraja ,&nbsp;S K Narasimhamurthy","doi":"10.1016/j.ijft.2025.101343","DOIUrl":"10.1016/j.ijft.2025.101343","url":null,"abstract":"<div><div><strong>Research Background:</strong> In the modern landscape of Industry 4.0 and technological advancements, the control of heat and fluid flow is critical in enhancing the performance and efficiency of industrial and energy systems. Hybrid nanofluids, due to their improved thermal conductivity and energy transport characteristics, have gained significant attention over conventional fluids.</div><div><strong>Issue:</strong> Despite their potential, the complex behaviour of hybrid nanofluids under the influence of magnetic fields, porous media, and thermal radiation remains insufficiently explored, especially for non-Newtonian models such as the Williamson fluid. A detailed understanding of these effects is essential for optimizing thermal systems.</div><div><strong>Method:</strong> This study investigates the Williamson hybrid nanofluid flow over a stretching sheet in a porous medium subjected to a magnetic field and thermal radiation. The governing nonlinear partial differential equations are converted into ordinary differential equations using similarity transformations and solved numerically using the Runge-Kutta-Fehlberg (RKF-45) method implemented in MAPLE-18. A regression model is also developed to predict skin friction and Nusselt number using key influencing parameters.</div><div><strong>Results:</strong> Convergence analysis demonstrates that the numerical solution remains stable and reliable within a relative tolerance range of 10⁻⁶ to 10⁻⁸. A multiple linear regression model, developed using key parameters <em>K</em>,  <em>M</em>,  <em>Rd</em>, and <em>Ec</em>, shows excellent predictive performance with <em>R</em>² = 0.96127 for the skin friction coefficient and <em>R</em>² = 0.99905 for the Nusselt number. These findings validate the robustness of the regression model and highlight the critical influence of magnetic and radiative parameters on heat transfer behavior in hybrid nanofluid flow systems.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101343"},"PeriodicalIF":0.0,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144702927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Viscous dissipative ternary nanoparticles on heat transfer enhancement in MHD flow over a stretching surface","authors":"Talha Anwar ,&nbsp;Syed Arshad Abas ,&nbsp;Mehreen Fiza ,&nbsp;Hakeem Ullah ,&nbsp;Seham M. Al-Mekhlafi","doi":"10.1016/j.ijft.2025.101327","DOIUrl":"10.1016/j.ijft.2025.101327","url":null,"abstract":"<div><div>A barrier that researchers and scientists are currently trying to overcome is the low thermal conductivity that occurs during heat transmission procedures. As a result, researchers are taking steps to improve the base fluid thermal conductivity by mixing it with different solid particles. This study examines the phenomena of heat and mass transfer in a two-dimensional magnetohydrodynamic (MHD) flow of a ternary hybrid nanofluid over a stretched surface. This study involved combining a water-based liquid with three distinct kinds of nanoparticles: graphene oxide, silver, and copper. Brownian motion, thermophoresis, Joule heating, viscous dissipation, and chemical reactions are also considered in the study. Convective and mass flux boundary conditions are incorporated at the surface of the boundary. The flow equations, which are treated in the form of higher-order nonlinear partial differential equations (PDEs), are transformed into ordinary differential equations (ODEs) by the utilization of similarity transformations. For the solution of the proposed non-linear problem, the bvp4c technique is used. For physical interpretation, the effect of various parameters on velocity, temperature, concentration, skin friction, Nusselt, and Sherwood numbers is discussed through graphs and tables. The skin friction improved for the ternary hybrid nanofluid against higher values of magnetic field and nanoparticle volume fraction. Incremental increase in the magnetic parameter, the velocity of the hybrid nanofluids, and ternary hybrid nanofluids are reduced. The heat transfer rate for the ternary hybrid nanofluid is 4.2% higher than that of the nanofluid for the same volume fraction of nanoparticles. The Sherwood number diminishes for ternary hybrid nanofluid against the nanoparticles volume fraction, whereas it boosts for the Schmidt number. The heat transfer rate improved 21% and 24% for ternary hybrid nanofluid against magnetic and Biot number, respectively.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101327"},"PeriodicalIF":0.0,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of geometrical parameters on thermohydraulic characteristics of plain fin-and-flat tube heat exchangers: A CFD and Taguchi approach","authors":"Luan Nguyen Thanh ,&nbsp;An Quoc Hoang","doi":"10.1016/j.ijft.2025.101340","DOIUrl":"10.1016/j.ijft.2025.101340","url":null,"abstract":"<div><div>The present work evaluated the effect of the geometrical parameters of plain fin-and-flat tube heat exchangers on the thermohydraulic characteristics of the air side in a laminar flow regime. The influence of a 21.4–25.4 mm transverse tube pitch, a 17–21 mm longitudinal tube pitch, and three flat-tube configurations with a constant cross-sectional perimeter were considered. The Taguchi method and a numerical simulation were applied in the analysis. The results indicated that the large longitudinal tube pitch and the flat tubes with a small aspect ratio yielded benefits in terms of the area goodness factor (AGF) and the thermohydraulic performance index (JF). The tube configuration had the highest influence on the JF and AGF, with a contribution percentage of 77.89–94.38 % and 70.36–81.33 %, respectively. The optimization analysis determined the configurations that yielded the highest AGF or JF. The optimal configurations resulted in an AGF increase of 40.8–67.5 % and a JF increase of 14.1–21.8 % compared with the configurations using circular tubes. The results can be referenced in the design of air-cooled heat exchangers using flat tubes in practical applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101340"},"PeriodicalIF":0.0,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144702926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of thermal storage improvement using RT 70 HC phase change material solidification in finned triplex tube heat exchangers","authors":"Atef Chibani ,&nbsp;Moustafa Boukraa ,&nbsp;Tawfiq Chekifi ,&nbsp;Ayele Tulu ,&nbsp;Toufik Benmalek","doi":"10.1016/j.ijft.2025.101342","DOIUrl":"10.1016/j.ijft.2025.101342","url":null,"abstract":"<div><div>The solidification process of liquids is considered one of the important processes in industrial activities; therefore, this research revolves around the solidification process of PCM material within an annular space with stuck fins on the internal surfaces. The study was conducted through a numerical simulation, employing a comprehensive approach to analyze heat transfer and phase change dynamics. The research was carried out under initial operational conditions, focusing on the impact of fin material and configuration on the solidification rate. The research aims to clarify the solidification process of PCM material as a function of time and under the change in the natural state of the fins. The tested materials are Carbon, Aluminum, Copper, and Steel, with their thermal conductivity and heat distribution properties being critically evaluated. Results demonstrate that fins significantly accelerate solidification, with Copper fins achieving 53.6 % faster phase change than the finless case at 1000 s, reducing the liquid fraction to 0.21 versus 0.41 without fins. The superior performance of Copper stems from its high thermal conductivity (385 W/m·K), enabling 22 % greater energy extraction compared to the baseline. Steel fins, with lower conductivity (50 W/m·K), showed limited effectiveness, highlighting the direct correlation between material properties and solidification rates. In addition, Steel fins have less influence on the solidification speed compared to other materials, primarily due to their lower thermal conductivity.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101342"},"PeriodicalIF":0.0,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical optimization of metal felt regenerators with axially varying matrix structures for Stirling engines","authors":"Sebastian Peveling,&nbsp;Hans-Detlev Kühl","doi":"10.1016/j.ijft.2025.101338","DOIUrl":"10.1016/j.ijft.2025.101338","url":null,"abstract":"<div><div>The regenerator is the crucial component for the performance of any regenerative gas cycle. Due to the changing gas properties and flow conditions in the axial direction of a regenerator, a variation of its parameters in that direction is a promising approach to reduce its losses and thus increase the performance of the cycle. This contribution presents the first comprehensive analysis of the potential of metal felt regenerators with axially varying parameters operated in a Stirling engine. For this purpose, a numerical optimization of an existing regenerator in an experimental machine is conducted using a well-validated differential model. To isolate the positive effects of the regenerator optimization, the thermal efficiency of the engine is optimized under the constraint of a constant power density. In general, the optimized matrix is characterized by increased porosity and decreased fiber diameter at the hot end of the regenerator, and vice versa at the cold end. The thermal efficiency of the engine is increased to 27.54 % for the optimized matrix compared to 27.06 % for the matrix with axially constant parameters. The optimal parameters depend on the operating point. For instance, the difference between the parameters at the cold and hot end decreases at a reduced heater temperature. Nevertheless, a regenerator optimized at the design operating point yields efficiency enhancements throughout the entire operating range, even though these enhancements decrease with increasing deviation from the design point. These promising findings contribute to the further improvement of Stirling engines and suggest pursuing an experimental validation.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101338"},"PeriodicalIF":0.0,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}