International Journal of Thermofluids最新文献

{"title":"Impact of radiation on MHD heat and mass transfer of Williamson nanofluid over a non-linear stretching sheet with melting and heat source - A numerical investigation","authors":"Anagandula Srinu ,&nbsp;K. Sreeram Reddy ,&nbsp;B. Shankar Goud","doi":"10.1016/j.ijft.2025.101231","DOIUrl":"10.1016/j.ijft.2025.101231","url":null,"abstract":"<div><div>The goal of this research is to analyze the heat transmission and MHD (Magnetohydrodynamics) Williamson nanofluid movement features across a non-linear stretching sheet contained in a permeable medium. In order to convert the leading formulation into ordinary differential equations(ODEs) form, a similarity conversions are used. The coupled equations, including non-linear components, are numerically solved using the built-in solver bvp4c in MATLAB. Using both graphical and tabular representations, the impacts of numerous dimensionless factors on the concentration category, friction factor, heat and mass transfer rates, and velocity are shown. An outstanding agreement is shown when the numerical findings are compared to previously published results. The findings that were obtained suggested that the increase in the Williamson parameter, the magnetic number, and the Prandtl number all contribute to a restriction in the velocity of the fluid. A wide range of factors, including the Williamson parameter, the thermophoresis factor, the heat source Brownian motion factor, the radiation parameter, and the Eckert number, have the potential to raise the temperature area. Schmidt and the chemical reaction parameter are responsible for the fall in the concentration distribution.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101231"},"PeriodicalIF":0.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912676","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":"Analyzing the effects of a Maxwell nanofluid with graphene oxide on rectangular, triangular, and chamfered baffles on the surface of a stretched surface","authors":"Mohammed Ali ,&nbsp;Rassol Hamed Rasheed ,&nbsp;Hasan A. Al-Asadi ,&nbsp;Saif Ali Kadhim ,&nbsp;Dhuha Radhi Nayyef ,&nbsp;Farhan Lafta Rashid ,&nbsp;Karrar A. Hammoodi ,&nbsp;Pooya Pasha","doi":"10.1016/j.ijft.2025.101247","DOIUrl":"10.1016/j.ijft.2025.101247","url":null,"abstract":"<div><div>The investigation of nanofluid (NF) flow under external fields and their influence on heat transfer rates has become a key focus in both engineering and medical sciences. Among these, magnetic fields have gained considerable attention in recent years owing to their unique properties and diverse applications. This study aims to examine the thermal and fluid dynamic performance of graphene oxide nanofluid flowing over different L-shaped baffles, employing a combination of analytical and statistical techniques. The surface stretches from two coordinates with a velocity of <em>u</em> = -2.6 m/s for <em>x</em> &lt; 0 and <em>u</em> = +2.6 m/s for <em>x</em> &gt; 0.The flow of nanofluids containing graphene oxide moves across the surface at a velocity of one unit in the y-direction, with a temperature of 25 °C. The innovation of this study lies in the first-time analysis of the fluidic and thermal parameters of graphene oxide nanofluid flowing over baffles with different shapes on a tensile surface. Additionally, by utilizing 20 numerical data points in Design Expert software, the optimal values for velocity, temperature, and magnetic parameters on a flat surface were determined. The results of this paper examine how to achieve optimal results through the use of design of experiments (DOE) and response surface methodology (RSM).It highlights that rising magnetic pressure currents and the development of magnetic vortices significantly decrease the nanofluid’s temperature and flow velocity. As the temperature difference within the fluid increases, energy is transferred between the nanofluid particles in contact with the surface. The optimization process led to notable improvements in the velocity, temperature, and magnetic characteristics of the graphene oxide nanofluid. The resulting optimal values were: velocity (u) at 1.19 m/s, temperature (T) at 10.83 °C, and magnetic parameter (H) at -0.232 T Furthermore, the optimized geometric parameters included a baffle spacing of 0.026, a baffle height of 0.085, and a page length of 1.119.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101247"},"PeriodicalIF":0.0,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261367","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 simulation of flow and mixing in fracture intersections","authors":"Qinjun Kang,&nbsp;Jeffrey D. Hyman,&nbsp;Philip H. Stauffer,&nbsp;Hari Viswanathan","doi":"10.1016/j.ijft.2025.101229","DOIUrl":"10.1016/j.ijft.2025.101229","url":null,"abstract":"<div><div>Fluid transport through fractured geological formations is strongly influenced by the redistribution of solutes at fracture intersections. In this study, we perform detailed numerical simulations of flow and scalar transport within the intersection of two smooth, planar fractures. The analysis focuses on the mixing ratio, the proportion of solute flux exiting along the outlet branch aligned with the primary inlet flow direction, relative to the total solute flux at the outlets. We systematically investigate how the mixing ratio varies with four key parameters: Peclet number, Reynolds number, flow rate ratio between outlet branches, and fracture intersection angle. Results show that the mixing ratio decreases with increasing Peclet number and outlet flow rate ratio, consistent with reduced diffusive spreading and enhanced streamline routing. While low Reynolds numbers have minimal impact, inertial effects at higher Reynolds numbers significantly increase the mixing ratio. Additionally, acute and obtuse intersection angles alter flow partitioning and modify the solute distribution at the outlets. These findings provide a quantitative basis for incorporating physically realistic mixing behavior—intermediate between complete mixing and streamline-following assumptions—into network-scale transport models. The results have direct relevance to subsurface energy systems, including geothermal energy production, carbon sequestration, and contaminant remediation.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101229"},"PeriodicalIF":0.0,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873567","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":"Experimental analysis of hydroxyapatite nanofluid for enhanced thermal performance in solar evacuated tube collectors","authors":"T. Sathish","doi":"10.1016/j.ijft.2025.101230","DOIUrl":"10.1016/j.ijft.2025.101230","url":null,"abstract":"<div><div>Sustainable Development Goals motivated this investigation for effective energy harvesting. Thermal performance enhancement helps sustainable energy practices by minimizing fossil fuel use while establishing cleaner energy technologies. The study uses hydroxyapatite and deionized water as working fluids with the mass flow rate of 0.5–1.5 lit/min to experimentally examine the thermal performance of heat pipe-based solar evacuated tube collectors. Samples of hydroxyapatite nanofluid with varying volume fraction as 0.05 %, 0.1 %, and 0.15 % have been used in deionized water. The structure of hydroxyapatite has been examined using a scanning electron microscope, and its structural characteristics were ascertained using X-ray diffraction. The Zeta potential measurement was performed to assess the permanency of the working fluid samples and revealed that the generated samples were stable for as long as 30 days. It was investigated and discussed how changing concentrations of the nanofluid affected its thermophysical characteristics. An impact mass flow rate and volumetric concentrations for nanofluid were considered when examining the thermal performance of SETC. In contrast with water, the thermal performance has been achieved at higher in SETC as 38.5 % at the volume fraction as 0.15 % at the mass flow rate as 1.5 lit/min. The results indicate that employing nanofluid samples significantly increases the temperature differential and energy gain. Based on research outcomes, these proposed findings are suitable for industrial and household applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101230"},"PeriodicalIF":0.0,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873387","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":"Design and hydrodynamic performance of low head propeller hydro turbine for wide range high efficiency operation","authors":"Thaithat Sudsuansee ,&nbsp;Suwat Phitaksurachai ,&nbsp;Rudklao Pan-Aram ,&nbsp;Noppong Sritrakul ,&nbsp;Yodchai Tiaple","doi":"10.1016/j.ijft.2025.101228","DOIUrl":"10.1016/j.ijft.2025.101228","url":null,"abstract":"<div><div>The primary aim of this investigation is to examine the design and hydrodynamic efficiency of a low head propeller hydro turbine tailored for efficient functionality within a diverse range of water head conditions, ranging from 3 to 11 m By employing sophisticated computational fluid dynamics (CFD) simulations and meticulous experimentation, the study endeavors to enhance the design parameters of the propeller hydro turbine to ensure peak efficiency and dependability. This investigation thoroughly examines various design factors, including the runner blade's angle, and the guide vane's angle, aiming to identify the most effective configuration that guarantees exceptional performance across various scenarios. The turbine demonstrated exceptional adaptability, achieving peak efficiencies of 76. 40 % at a head of 3 m, 77.34 % at 7 m, and 78.03 % at 11 m, with a maximum power output of 81.09 kW achieved at 11 m and 800 RPM. These results highlight the turbine's ability to maintain high performance across varying hydraulic conditions. Emphasis is particularly placed on establishing accurate boundary conditions, incorporating turbulent modeling through the Shear Stress Transport (SST) k-ω model, and utilizing advanced mesh generation techniques, notably the Poly-Hexcore mesh technology. By integrating advanced simulation approaches and meshing methodologies, this research aims to refine the precision and effectiveness of turbine design procedures, ultimately contributing to the progression of sustainable energy generation technologies. The outcomes of this study are anticipated to make a substantial contribution to the realm of renewable energy production by enhancing the comprehension and enhancement of low head propeller hydro turbine technology for superior performance and sustainability in energy generation.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101228"},"PeriodicalIF":0.0,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863712","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":"A comprehensive review on natural convection in trapezoidal cavities with mono and hybrid nanofluids","authors":"Farhan Lafta Rashid ,&nbsp;Zainab Abdul Karim Alkhekany ,&nbsp;Muhammad Asmail Eleiwi ,&nbsp;Abdallah Bouabidi ,&nbsp;Shabbir Ahmad ,&nbsp;Atef Chibani ,&nbsp;Mohamed Kezzar ,&nbsp;Saif Ali Kadhim ,&nbsp;Ali Habeeb Askar ,&nbsp;Karrar A. Hammoodi","doi":"10.1016/j.ijft.2025.101226","DOIUrl":"10.1016/j.ijft.2025.101226","url":null,"abstract":"<div><div>This review synthesises advancements in natural convection within trapezoidal cavities using mono- and hybrid nanofluids, emphasising their geometric advantages for thermal management. Trapezoidal cavities promote asymmetric flow patterns that enhance heat transfer compared to conventional geometries, as demonstrated in applications like solar absorbers and electronic cooling. Through analysis of 50+ previous studies, the review identifies key trends: Hybrid nanofluids like Cu-Al₂O₃/water consistently outperform mono nanofluids in Nusselt number improvement, with gains exceeding 20 %. Inclined walls mitigate stagnant flow zones, though exact reduction rates vary with aspect ratio and nanoparticle concentration. Magnetic fields and porous media further modulate thermal performance, but trade-offs emerge between conductivity enhancement and viscosity penalties. This review provides a framework to optimise trapezoidal cavities with nanofluids for industrial deployment.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101226"},"PeriodicalIF":0.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860715","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":"Experimental study on flow properties of jojoba oil-diesel fuel blends with/without alcohols additives","authors":"Mamdouh Ghannam ,&nbsp;Mohamed Y.E. Selim ,&nbsp;Ahmed Thaher ,&nbsp;Budoor Aljneibi ,&nbsp;Fajr Alhammadi ,&nbsp;Buthaina Albreiki","doi":"10.1016/j.ijft.2025.101227","DOIUrl":"10.1016/j.ijft.2025.101227","url":null,"abstract":"<div><div>The flow characteristics of different jojoba oil–diesel fuel blends (JDFBs) with and without additives (diethyl ether or Butanol at 5, 10 or 15 %) were experimentally examined to assess their flow performance in comparison with diesel fuel. The density and kinematic viscosity of jojoba oil, diesel fuel, and their blends were measured using an SVM 3000 Stabinger Viscometer (Anton Paar). Rheograms and viscosity–shear rate profiles were derived using the MCR 92 Modular Compact Rheometer. The density of pure diesel fuel increases slightly upon the addition of jojoba oil. For example, at 40 °C, the density increases from 0.813 g/cm³ for pure diesel to 0.87 g/cm³ for the JDFB with 50 % jojoba oil content. Moreover, the kinematic viscosity increases gradually with jojoba oil content, ranging from 4.06 cSt for pure diesel to 4.76, 9.16, and 20.30 cSt for JDFBs containing 10 %, 25 %, and 50 % jojoba oil at 20 °C, respectively. The power-law model can predict the flow behavior of JDFBs up to 50 % jojoba oil content. The dynamic viscosity increases from 3.60 mPa.s for pure diesel to 4.97, 6.75, and 12.17 mPa.s for JDFBs containing 10 %, 25 %, and 50 % jojoba oil, respectively, at 20 °C. The increase in the viscosity of the blend was managed either by heating and / or adding non-viscous alcohols. At 60 °C, the viscosity reduction reaches approximately 64 % for the JDFB with 50 % jojoba oil content. The viscosity reduction is more notable when using diethyl ether as an additive than when using butanol. For instance, the 15 % of Butanol addition, caused the viscosity of the blend to be very much comparable to the diesel fuel.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101227"},"PeriodicalIF":0.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868798","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":"Unsteady Williamson nanofluid flow over a rotating cone: Effects of variable properties, thermal radiation, and chemical reactions","authors":"Endale Ersino Bafe,&nbsp;Mitiku Daba Firdi,&nbsp;Lemi Guta Enyadene","doi":"10.1016/j.ijft.2025.101211","DOIUrl":"10.1016/j.ijft.2025.101211","url":null,"abstract":"<div><div>This study investigates the unsteady flow of Williamson nanofluid over a vertically rotating cone, incorporating the effects of variable thermophysical properties, chemical reactions, and thermal radiation. A self-similarity transformation reduces the governing PDEs to ODEs. The spectral relaxation method is utilized for numerical solutions under specified wall temperature and concentration (SWTC), as well as specified thermal and solutal flux (STSF) conditions. A grid independence and residual norm analysis confirm the robustness of the numerical scheme, which is further benchmarked against standard solvers. A parametric sensitivity analysis, involving <span><math><mrow><mo>±</mo><mn>20</mn><mtext>%</mtext></mrow></math></span> perturbations, identifies the most influential parameters affecting thermal and solutal transport. Results reveal that tangential and azimuthal momentum components exhibit inverse responses to parameter variations. Variable thermal conductivity and solutal diffusivity enhance temperature and concentration fields under SWTC conditions but reduce them in the STSF scenario. A simultaneous increase in variable viscosity and suction/injection parameters significantly elevates the tangential and azimuthal skin friction coefficients. The Nusselt number rises by 58.34% with simultaneous increases in variable thermal conductivity and linear radiation parameters, and by 81.10% when nonlinear radiation parameter is considered instead, highlighting the effectiveness of nonlinear radiation in enhancing thermal performance. Moreover, chemical reactions increase mass transfer, while enhanced variable diffusivity suppresses it. The findings offer practical insights for optimizing heat and mass transfer in rotating systems such as drilling and rotary filtration units.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101211"},"PeriodicalIF":0.0,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868799","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":"Heat transfer improvement in turbulent flow using detached obstacles in heat exchanger duct","authors":"Omar Ghoulam ,&nbsp;Hind Talbi ,&nbsp;Kamal Amghar ,&nbsp;Abdel-illah Amrani ,&nbsp;Adil Charef ,&nbsp;Ismael Driouch","doi":"10.1016/j.ijft.2025.101225","DOIUrl":"10.1016/j.ijft.2025.101225","url":null,"abstract":"<div><div>The current study aims to enhance the effectiveness of a cooling system by introducing vertical and detached obstacles within a rectangular channel to create singularities in the flow. This study focuses on a numerical simulation to investigate the effects of these detached obstacles on forced convective airflow (cooling fluid) in a turbulent flow within a heat exchanger's rectangular channel. The mathematical model governing the fluid flow and heat transfer is based on the Finite Volume Method (FVM) and solves the Navier-Stokes equations under the assumption of steady-state, incompressible flow with constant fluid properties. Two types of obstacles were considered: planar (Type A) and diamond-shaped (Type B), with four different spacings (S = s/2, S = s, S = 5s/4, and S = 3s/2). The simulations were carried out for Reynolds numbers (Re) ranging from 20,000 to 35,000. The CFD calculations employed the SIMPLE algorithm with the QUICK scheme for discretizing the governing equations. The analysis included the impact of obstacle geometry and spacing on hydrothermal interactions, focusing on axial velocity, dynamic pressure, local and average Nusselt numbers, friction factor, and thermal enhancement factor. The results show that diamond-shaped obstacles significantly outperform planar obstacles in terms of both hydrothermal performance and thermal enhancement. Additionally, increasing the distance between the detached obstacles leads to a higher average Nusselt number.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101225"},"PeriodicalIF":0.0,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868880","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":"Comparative analysis of machine learning models for wind speed forecasting: Support vector machines, fine tree, and linear regression approaches","authors":"Yousef Altork","doi":"10.1016/j.ijft.2025.101217","DOIUrl":"10.1016/j.ijft.2025.101217","url":null,"abstract":"<div><div>Wind speed is an important parameter of wind energy conversion, and its forecast is significant for optimal power generation and maintaining the stability of the electricity supply. In this work, three predictive models, namely Fine Tree, Support Vector Machine (SVM), and Linear Regression, are assessed using meteorological data from the National Wind Technology Center (NWTC) in Boulder, Colorado, for the period 2019–2023. The meteorological variables that have been incorporated into the dataset are wind direction, air temperature, relative humidity, atmospheric pressure, precipitation, and wind speed at 50 m height. The evaluation of the performance of the models used Root mean squared error (RMSE), mean squared error (MSE), mean absolute error (MAE), and coefficient of determination (R²). The findings show that the Linear Regression model has the best accuracy (RMSE = 0.29555, MSE = 0.08735, MAE = 0.18061, R² = 0.97), followed by the SVM model (RMSE = 0.32275, R² = 0.96) and then the Fine Tree model (RMSE = 0.44042, R² = 0.93). These results have demonstrated Linear Regression in enhancing wind speed prediction, where future studies should investigate the combination of the forecasted models or other different machine learning models to improve the accuracy of prediction internationally.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101217"},"PeriodicalIF":0.0,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863709","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}