International Journal of Thermofluids最新文献

{"title":"A comprehensive analysis of combustion efficiency and emissions in biodiesel blends for sustainable energy solutions","authors":"Ratchagaraja Dhairiyasamy ,&nbsp;Saurav Dixit ,&nbsp;Subhav Singh ,&nbsp;Deepika Gabiriel","doi":"10.1016/j.ijft.2025.101357","DOIUrl":"10.1016/j.ijft.2025.101357","url":null,"abstract":"<div><div>The urgent global demand for clean and renewable fuels has intensified research into biodiesel production from non-edible oil feedstocks. Among them, Sterculia foetida and mango seed oils represent promising, underutilized resources. However, challenges such as inferior fuel properties and higher NOx emissions hinder their widespread adoption. To overcome these limitations, this study evaluates the performance, combustion, and emission characteristics of a biodiesel blend (BSM20) synthesized from Sterculia foetida and mango seed oils, modified with bio-based antioxidants derived from neem (NLA), eucalyptus (ELA), and Pongamia (PLA) leaf extracts. The biodiesels were blended with 20 % diesel and tested in a single-cylinder, four-stroke CI engine at varying loads. Physicochemical characterization showed improved cetane numbers (52–54) and flash points (137–140 °C), meeting ASTM D6751 standards. At full load, BSM20-NLA recorded the lowest BSFC at 0.488 kg/kWh, a 4.5 % improvement over BSM20 and only 1.2 % higher than diesel. BTE for BSM20-PLA reached 32.19 %, close to diesel's 33.04 %. CO and HC emissions decreased by 36.84 % and 22.22 %, respectively, while NOx emissions were reduced by 17.72 % for BSM20-NLA. Smoke opacity was lowered by 13.83 % with NLA. Combustion analysis revealed a 44.95 % shorter ignition delay and a peak pressure of 74 bar for BSM20-NLA, only 2.63 % below diesel. The rate of pressure rise (RPR) improved across all additive blends, indicating enhanced combustion efficiency. The addition of natural leaf additives also helped suppress oxidation and thermal degradation, improving fuel stability. These results demonstrate that incorporating plant-based antioxidants into biodiesel blends can significantly optimize engine performance and reduce environmental impact. Future research should focus on long-term engine wear analysis and scalability for commercial deployment.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101357"},"PeriodicalIF":0.0,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773017","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":"Fuzzy volume fraction model representation of blood-based sisko tri-hybrid nanofluid flow via a stretching cylinder","authors":"N. Deepa ,&nbsp;P. Kavya ,&nbsp;N. Thamaraikannan ,&nbsp;S. Madhanraj ,&nbsp;P. Asaigeethan ,&nbsp;K. Loganathan","doi":"10.1016/j.ijft.2025.101354","DOIUrl":"10.1016/j.ijft.2025.101354","url":null,"abstract":"<div><div>A modified variant of Buongiorno's model was used to analyze the transfer of a ternary hybrid nanofluid (thnf) across a stretched cylinder using the Sisko fluid model. The effect of homogeneous-heterogeneous reactions on the chemical process for the nanoparticle concentration is considered. The dispersion has resulted in the formation of a ternary hybrid nanofluid consisting of titanium dioxide (TiO₂), gold (<em>Au</em>), and silver (<em>Ag</em>) nanocomposites in a base fluid (blood). A system of partial differential equations (PDEs) determines the fluid flow, considering the impact of a heat source, magnetic induction, and natural convection. The process involves using substitutions for similarity variables to convert them into a collection of non-dimensional ordinary differential equations (ODEs). This analysis specifically examines the no-slip assumption, which results in a nonlinear Dirichlet boundary condition for axial velocity. A triangular fuzzy number (TFNs) with the range [0, 0.5, 1.0] is used to analyze the unknown volume of ternary hybrid nanoparticles consisting of TiO₂, <em>Au</em>, and <em>Ag</em>. The triangular membership function (TMF) is utilized to analyze the variability of uncertainty, while the α− <em>cut</em> is responsible for controlling the TFNs. Analysis of fuzzy linear regression analysis utilizes triangular fuzzy numbers (TFNs) to ascertain the central (crisp), left, and right values of the fuzzy velocity profile. The study's findings and the fuzzy velocity profile exhibit the highest flow rate when compared to the crisp velocity profile at its midpoint. Material, curvature, and magnetic field parameters determine the velocity field of the reaction in ternary hybrid nanofluid (TiO₂+ <em>Au</em> +Ag)/Blood), hybrid nanofluid (TiO₂+ <em>Au</em> /Blood), and nanofluid (TiO₂/Blood). The curvature parameter and magnetic field parameter influence the heat conduction of the reaction in thnf, hnf, and nanofluid. The Schmidt number and homogeneous-heterogeneous reaction parameter determine the concentration profile of the reaction in thnf, hnf, and nanofluid. Tables and graphs present the evaluation results for velocity, temperature, concentration, the coefficient of skin friction, the local Sherwood number, and the local Nusselt number.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101354"},"PeriodicalIF":0.0,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773015","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":"Thermal and solutal analysis of local thermal non-equilibrium effects on gyrotactic microbes in radiative flow of hybrid nanofluid with Soret–Dufour effects","authors":"Munawar Abbas ,&nbsp;Mostafa Mohamed Okasha ,&nbsp;Tatyana Orlova ,&nbsp;Ali Akgül ,&nbsp;Murad Khan Hassani ,&nbsp;Saba Liaqat","doi":"10.1016/j.ijft.2025.101355","DOIUrl":"10.1016/j.ijft.2025.101355","url":null,"abstract":"<div><div>The present research investigates the impact of local thermal non-equilibrium on radiative flow of a hybrid nanofluid around a revolving sphere in the presence of gyrotactic microbes and porous medium. To explore heat transfer characteristics in cases where LTE (local thermal equilibrium) is not assumed, the research provides use of a basic mathematical model. In LTNE conditions, the solid and liquid phases experience distinct thermal gradients. SWCNTs (Single-walled carbon nanotubes) and MWCNTs (multi-walled carbon nanotubes) suspended in water make up the hybrid nanofluid under discussion. In order to compare the modified model's heat transfer performance with that of the conventional Hamilton-Crosser model, this study specifically concentrate at the hybrid nanofluid that consists of MWCNTs, SWCNTs, and water. To convert the constitutive equations into ODEs, similarity variables were used. and MATLAB's Bvp4c function has been employed to find solutions. The results suggest that relative to the modified model, classical model can predict increased heat transmission rates with adequate precision. The findings improve the precision of models for thermal conductivity and advance our considerate of the properties of hybrid nanofluid heat transfer. The solid-phase thermal field and the liquid-phase thermal transmission rate both decrease with increasing interphase heat transfer factor in both the modified and classical Hamilton–Crosser models.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101355"},"PeriodicalIF":0.0,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144756748","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":"Oil-cooled transformer hot spot temperature reduction using windings height optimum design","authors":"Mohammad Ali Taghikhani","doi":"10.1016/j.ijft.2025.101353","DOIUrl":"10.1016/j.ijft.2025.101353","url":null,"abstract":"<div><div>Transformers are used in transmission and distribution of electrical energy in the power network. Thus, electrical and physical optimization of transformers are important. On the other hand, estimation of the temperature rise and reduction of the hot spot temperature (HST) in a transformer increase the loading capability and life span of the transformer. In this paper, characteristics of an oil-immersed transformer is optimized and minimum losses of the transformer is calculated. For this purpose, the meta-heuristic modified Arctic Puffins optimization (MAPO) algorithm is used to optimize the transformer design. Moreover, temperature distribution in the transformer windings are simulated in different load conditions using a numerical method based on heat transfer theory and heat conduction equation. Besides, the effects of the transformer winding dimensions on the HST are investigated in different load conditions. The results show that the HST value in the windings is minimized at a specific height of the windings. Furthermore, the proposed method for the HST estimation seems to correspond with the results of FEM modeling and measurements in the previous works.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101353"},"PeriodicalIF":0.0,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739568","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":"Enhanced turbomachinery capabilities for OpenFOAM: Validation and integration of a CAD solution and mixing-plane","authors":"Lorenz Hammerschmidt,&nbsp;Zlatko Raonic","doi":"10.1016/j.ijft.2025.101341","DOIUrl":"10.1016/j.ijft.2025.101341","url":null,"abstract":"<div><div>This study presents an enhanced, open-source workflow for turbomachinery design and simulation by integrating a fully parametric CAE solution (<em>pyTurbo</em>) with a modified OpenFOAM solver (<em>turboSimpleFoam</em>) capable of handling mixing-plane interfaces and rothalpy-based energy modelling. The new workflow bridges the gap between geometry generation and compressible CFD analysis for radial machines, enabling rapid, scriptable, and reproducible design iterations. The underlying geometry engine, <em>pyNURBS</em>, offers robust NURBS-based operations for high-fidelity construction of turbomachinery components including blades, casings, and volutes. The framework is validated using the Sundstrand Power Systems T-100 radial turbine as a benchmark, comparing geometry and simulation results with ANSYS BladeGen, ANSYS CFX, and experimental data. Results demonstrate strong agreement in geometry and performance metrics, with efficiency deviations below 2% and mass flow errors under 1%, confirming the viability of the framework as an open-source alternative to commercial CAE pipelines. Moreover, this implementation establishes a solid foundation for future research in turbomachinery design, including structural analysis, multi-region solving, and automated optimisation loops, thereby enabling seamless integration of CAD and CFD workflows within the OpenFOAM ecosystem.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101341"},"PeriodicalIF":0.0,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144772954","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":"Large-eddy simulations of separated flow and heat transfer in a rib-roughened channel","authors":"Himani Garg,&nbsp;Christer Fureby","doi":"10.1016/j.ijft.2025.101332","DOIUrl":"10.1016/j.ijft.2025.101332","url":null,"abstract":"<div><div>Ribbed channel flows play a crucial role in various engineering systems where turbulence enhancement and improved heat transfer are required, such as in turbine blade cooling and combustor wall applications. Numerical simulations have emerged as an essential tool for analyzing the intricate turbulence dynamics and flow separation phenomena, which are fundamental for optimizing the channel performance. This work presents a comparative analysis of turbulence modeling approaches, specifically Reynolds-Averaged Navier–Stokes (RANS) and Large Eddy Simulations (LES), using OpenFOAM across Reynolds numbers of 4000, 8000, 12000, 16000, 22000, and 24000. Multiple turbulence models, subgrid-scale models, and mesh resolutions are examined to assess their influence on the accuracy of flow and thermal transfer predictions. The numerical results, particularly in terms of turbulence characterization and its effect on thermal performance, are validated against the experimental data of Wang (2007). The mesh sizes vary between 1 and 25 million cells, capturing around 90% of the turbulent energy, suggesting that the LES meshes provide sufficient resolution. Overall, LES results exhibit stronger agreement with experimental observations compared to RANS predictions, with WALE and LDKM subgrid models demonstrating superior performance relative to SMG and OEEVM. Additionally, to deepen the understanding of turbulence mechanisms governing flow separation, reattachment, and eventually redevelopment, we present extensive analyses of flow parameters, e.g., mean velocity, friction coefficient and Reynolds shear stress. The anisotropic characteristics of turbulence at all scales are examined using anisotropic invariant maps, revealing substantial variations in anisotropy across different near-wall regions between consecutive ribs.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101332"},"PeriodicalIF":0.0,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722725","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":"Thermal performance and flow control in cross-flow heat exchangers using inclined splitter plate","authors":"Sachin Kaushik ,&nbsp;Harvindra Singh ,&nbsp;Pravat Ranjan Pati ,&nbsp;Jayant Giri ,&nbsp;T Sathish ,&nbsp;Mohammad Kanan ,&nbsp;Sunil Chamoli ,&nbsp;Chandra Kishore","doi":"10.1016/j.ijft.2025.101351","DOIUrl":"10.1016/j.ijft.2025.101351","url":null,"abstract":"<div><div>The impact of inclined splitter plates on wake dynamics, heat transfer properties, and pressure drop in a flow around a circular cylinder at Reynolds numbers 5500, 8500, 11,500, and 14,500 is examined numerically in this work. To determine their impact on flow structures and convective heat transfer, the splitter plate length-to-diameter ratios (L/D) of 0, 0.5, 2, and 3 as well as the inclination angles of 0°, 15°, and 30° are examined. The Nusselt number increased by the largest percentage, 78.82 %, at α = 30° at Re = 5500. For instance, the increase in the Nusselt number reached 50.91 % at Re = 11,500 &amp; 47.64 % at Re = 14,500. The results show that raising the inclination angle improves heat transmission performance. At α = 30° and Re = 5500, the performance evaluation criterion (PEC) peaks at 3.49, indicating a substantial trade-off between pressure loss and heat transfer enhancement. Heat transfer improves with increasing L/D, reaching a maximum at L/<em>D</em> = 3, according to an analysis of the influence of splitter plate length (L/D) at α = 15° At L/<em>D</em> = 2, the PEC value is maximum, suggesting that pressure loss and heat transfer enhancement are optimally balanced. But pressure penalties increase significantly when L/<em>D</em> = 2. At Re = 5500, the Nusselt number increases by 25.4 %, from 37.17 at L/<em>D</em> = 0.5 to 46.65 at L/<em>D</em> = 3. Similarly, the Nusselt number rises at Re = 14,500 from 78.90 at L/<em>D</em> = 0.5 to 85.20 at L/<em>D</em> = 3. The coefficient of friction exhibits an increasing trend with increasing L/D, peaking at 0.189 for L/<em>D</em> = 3 and Re = 5500. By aligning with contour and streamline patterns that validate the wake flow adjustments, the study offers insight into optimizing splitter plate layouts for enhanced heat exchanger performance.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101351"},"PeriodicalIF":0.0,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773016","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":"Evaluating the viscous dissipation effect on dusty boger hybrid nanofluid with applications of cattaneo-christov approach: Xue and Yamada–Ota models","authors":"Munawar Abbas ,&nbsp;Mostafa Mohamed Okasha ,&nbsp;Barno Abdullaeva ,&nbsp;Jihad Younis ,&nbsp;Mohammed Tharwan ,&nbsp;Saba Liaqat","doi":"10.1016/j.ijft.2025.101350","DOIUrl":"10.1016/j.ijft.2025.101350","url":null,"abstract":"<div><div>This study aims to investigate the effects of viscous dissipation on the flow of a dusty Boger hybrid nanofluid over a plate using variable thermal conductivity and the CattaneoChristov heat flux model. The goal of this work is to use sodium alginate fluids to determine the hybrid nanofluid's thermal mobility. For the thermal behaviour, <em>Cu</em> and A<em>l</em>₂O₃ are used as the nanoparticles. It is particularly useful in industrial processes including polymeric and non-Newtonian fluids, such as in extrusion, chemical processing, cooling of electronic equipment, and thermal management in energy systems. The inclusion of hybrid nanoparticles enhances thermal performance, while the consideration of thermal relaxation effects via the CattaneoChristov model makes the analysis more realistic for high-temperature and microscale applications. Moreover, the presence of dust particles adds relevance to areas like aerospace engineering, combustion systems, and particulate-laden flows in environmental and biomedical fields. An appropriate transformation strategy is applied to transform PDEs into ODEs. The shooting method is used to establish the numerical solution. The results demonstrate that the Boger hybrid nanofluid displays an improved flow field and a lowering liquid phase thermal field for higher values of the solvent fraction factor.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101350"},"PeriodicalIF":0.0,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144757362","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":"An optimized cubic B-spline algorithm for high-precision approximation of nonlinear transport phenomena","authors":"Rabia Noureen ,&nbsp;Muhammad Kashif Iqbal ,&nbsp;Maryam Asgir ,&nbsp;Bandar Almohsen ,&nbsp;Muhammad Azeem ,&nbsp;Husam A. Neamah","doi":"10.1016/j.ijft.2025.101331","DOIUrl":"10.1016/j.ijft.2025.101331","url":null,"abstract":"<div><div>This study aims to investigate a numerical scheme based on etics, Riphah Internatxtended cubic B-spline functions for solving the nonlinear gas dynamics equation, which plays a crucial role in the study of physical phenomena such as explosions, combustion, detonation and condensation within moving flows. The standard finite difference formulation has been employed to approximate the time derivative, while the solution curve in spatial direction is interpolated using extended cubic B-spline functions. A comprehensive stability analysis of the scheme is provided to ensure that errors do not propagate over time. Additionally, a convergence analysis for cubic B-spline interpolation is conducted to assess the accuracy of the solution. The effectiveness and efficiency of the proposed method are tested through numerical simulations. The findings indicate that the proposed technique provides better error estimates compared to other methods discussed in the literature. The straightforward algorithm, high accuracy and minimal computational efforts are the major advantages of this approach. Therefore, the proposed method may serve as a promising and efficient alternative for the numerical solution of nonlinear partial differential equations.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101331"},"PeriodicalIF":0.0,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713901","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":"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}