International Journal of Thermofluids最新文献

{"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}

{"title":"Conjugated role of variant-shaped ternary hybrid nanoparticles in MHD Jeffery–Hamel Water-EG flows: New mathematical model","authors":"Nawel Benaziza ,&nbsp;Rania Saadeh ,&nbsp;Ayman A. Dawod ,&nbsp;N.F.M. Noor ,&nbsp;Ahmad Qazza ,&nbsp;Mohamed Kezzar ,&nbsp;Mohamed. Rafik. Sari","doi":"10.1016/j.ijft.2025.101224","DOIUrl":"10.1016/j.ijft.2025.101224","url":null,"abstract":"<div><div>Present investigation uncovers thermal performance of MHD Jeffery-Hamel flows of water-ethylene glycol volume-equivalent mixtures drenched with ternary hybrid moly-alumina-titania nanoparticles of various shapes in the same base fluid (i.e. EG-H₂O〈50 %-50 %〉). The new mathematical model has been proposed to befit thermo-physical characteristics of the ternary nanofluid that encompasses the nanoparticles with distinct viscosities and thermal conductivities. In the primal stage, the governing PDEs are reduced to ODEs using the similarity reformations. In the next stage, the ensuing equations are dealt both numerically by applying the 4th-5th order Runge-Kutta-Fehlberg method and analytically through the adoption of Duan–Rach Adomian approach. The present findings are compared with the results of HAM-based Mathematica BVPh 2.0 package and those available from the literatures for several selected cases. The variations of tested parameter (i.e. Reynolds number <em>Re</em> ∈ [40∶ 274], Hartmann number ‘’Ha ∈ [0∶ 1000] and volume fraction is φ∈ [0∶ 0,08]) in stream and temperature profiles as well as in skin friction and Nusselt number are analyzed under the effects of variant parameters of interest such as nanoparticle volume fraction and nanoparticle shape factor. Finally the significant remarks from the findings are also concluded. The addition of solid nanoparticles to EG-water mixtures increases skin friction, causing a toll on the surface. The Nusselt number reveals unique contributions of each nanoparticle, with increasing <em>MoS</em>₂ or <em>Al</em>₂<em>O</em>₃ nanoparticles deterring heat flux performance. However, adding <em>TiO</em>₂ nanoparticle volume fraction alone boosts heat transfer performance in ternary hybrid water-EG nanoliquids passing through convergent-divergent channels.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101224"},"PeriodicalIF":0.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860719","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":"Enhancing thermal performance of water-air cross flow heat exchangers through upstream nozzle design and unit division","authors":"Mahmoud Khaled","doi":"10.1016/j.ijft.2025.101223","DOIUrl":"10.1016/j.ijft.2025.101223","url":null,"abstract":"<div><div>Improving water-air cross-flow heat exchangers' (HXs') thermal performance is essential for raising energy efficiency in a range of industrial applications. In order to accomplish this, prior research has mostly concentrated on altering interior geometries or flow configurations. Nevertheless, scarce are the studies about the possibilities of manipulating external airflow. This work presents and assesses a unique method for externally altering airflow arrangements in order to maximize the thermal performance of water-air cross-flow HXs. In contrast to conventional techniques that focus on internal adjustments, this study suggests a novel exterior approach that divides the HX into several smaller, face-to-face units inside the airflow and uses an upstream nozzle to boost airflow velocity over a smaller region. The goal of this design is to increase thermal efficiency without changing the HX's internal structure. To mimic the operation of a double-passage HX under various circumstances, a two-dimensional computational model was created and verified. The model evaluated the proposed HX designs' and the conventional designs' thermal performance over a variety of water flow rates and air velocities. According to the simulations, the suggested design can increase thermal performance by up to 6.1 % when compared to the conventional HX setup. Interestingly, these improvements are particularly noticeable at greater water flow rates (12,000 L/h) and moderate mean air velocities (6 m/s). Crucially, these enhancements are made without causing extra pressure drop, highlighting the design's potential for real-world uses.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101223"},"PeriodicalIF":0.0,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863710","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 photovoltaic cooling using ZnO/TiO₂ hybrid nanofluids: numerical and experimental analysis","authors":"Zaid Ali Shaalan ,&nbsp;Adnan Mohammed Hussein ,&nbsp;Mohd Zulkifly Abdullah ,&nbsp;Ahmed Mohsin Alsayah ,&nbsp;Mohammed J. Alshukri ,&nbsp;Mahmoud Khaled","doi":"10.1016/j.ijft.2025.101222","DOIUrl":"10.1016/j.ijft.2025.101222","url":null,"abstract":"<div><div>Overheating frequently results in decreased operating efficiency for photovoltaic (PV) panels, which impairs their capacity to efficiently convert solar energy. In order to improve PV system thermal management, this work examines the cooling efficacy of a ZnO/TiO₂ hybrid nanofluid at a concentration of 0.02 %. This study examines the cooling performance of air-cooled, water-cooled, and hybrid nanofluid-cooled PV panels in a new way by combining numerical models with real testing. It focuses on temperature changes and how they affect power production and electrical efficiency. Three identical PV panels were cooled using water, air, and hybrid nanofluid cooling techniques. In order to evaluate temperature variations, electrical efficiency, and power output for every cooling method, computational fluid dynamics (CFD) simulations were used in conjunction with experimental testing. When compared to air cooling at 1:00 pm., the electrical efficiency using the hybrid nanofluid cooling technique was increased by 12.1 % and by 8.2 % when using water cooling. Notably, water cooling achieved a 7.0 % reduction in panel temperature, while hybrid nanofluid cooling reduced it by 10.4 %. These findings suggest that hybrid nanofluids hold significant potential for improving PV performance, offering an effective solution to enhance solar energy system efficiency.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101222"},"PeriodicalIF":0.0,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854372","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 semi-analytical analysis on transfer behaviour of heat and mass on the viscous dissipated MHD UCM fluid flow between squeezing plates","authors":"Pareekshith G. Bhat ,&nbsp;Ali J. Chamkha ,&nbsp;Nityanand P. Pai ,&nbsp;Sampath Kumar V.S.","doi":"10.1016/j.ijft.2025.101202","DOIUrl":"10.1016/j.ijft.2025.101202","url":null,"abstract":"<div><div>The current study strives to theoretically examine the heat and mass transfer properties on the magnetohydrodynamic upper convected Maxwell fluid flow through a squeezing channel of parallel plates. Due to its vast applications, such as lubrication systems and bearing, the flow of upper convected Maxwell fluid through the channel comprising a moving impermeable top plate and a stationary porous bottom that is responsible for injection and suction effects in addition to squeezing motion is analysed in the study. The fundamental equations governing the conservation laws of fluid mechanics are transfigured into a non-linear system of ordinary differential equations adopting similarity transformations along with the boundary conditions. The so-obtained non-linear ordinary differential equations are then approached by the homotopy perturbation method to achieve an approximate analytic solution. Various graphs concerning the velocity, temporal, and concentration profiles are plotted against distinct pertinent parameters that pose a physical impact on the model. It is observed that the temporal distribution field elevates with a rise in the Eckert number and a decrease in the radiation parameter. Further, it is noticed that the concentration profile upsurges with a hike in the radiation parameter and depletion in the Eckert number. Moreover, the numerical values corresponding to the coefficient of skin friction, and rates of heat and mass transfer are tabulated for distinct pertinent parameters involved in the study.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101202"},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837832","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":"Impact of climate conditions on the performance of adaptive air handling unit","authors":"Madhwesh N ,&nbsp;Sampath Suranjan Salins ,&nbsp;Shiva Kumar","doi":"10.1016/j.ijft.2025.101220","DOIUrl":"10.1016/j.ijft.2025.101220","url":null,"abstract":"<div><div>Thermal comfort inside the Building space, houses, and offices are controlled by using the heating, ventilation, and air conditioning (HVAC) systems. To reduce energy consumption and achieve optimal performance, building automation plays a crucial role. This work focuses on a detailed analysis of the air handling unit, which is used to maintain thermal comfort within a room in a Dubai Climatic conditions. An air handling unit was constructed for the study, and experiments were conducted under various climatic conditions to assess the performance of the humidifier and dehumidifier and their impact on thermal comfort within the room. The results showed that the system achieved a maximum dehumidification efficiency of 96.06 %, a moisture removal rate of 2.25 g/s, an evaporation rate of 0.16 g/s, and a coefficient of performance of 0.8. The thermal comfort parameters, including Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD), remain within acceptable limits for inlet temperatures of 25 °C and 40 °C across all inlet relative humidity values. However, temperatures outside these ranges did not fall within the thermal comfort limits. It was found that energy and cost savings per hour amounted to 22.85 %.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101220"},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868800","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":"Prediction of R1234yf flow boiling behavior in horizontal, vertical, and inclined tubes using machine learning techniques","authors":"Farzaneh Abolhasani,&nbsp;Behrang Sajadi,&nbsp;Mohammad Ali Akhavan-Behabadi","doi":"10.1016/j.ijft.2025.101219","DOIUrl":"10.1016/j.ijft.2025.101219","url":null,"abstract":"<div><div>In the present study, the utilization of machine learning algorithms (MLAs) is proposed for the prediction of the heat transfer coefficient and pressure drop in horizontal, vertical, and inclined tubes during flow boiling of R1234yf. A total of 339 experimental data points sourced from the literature are employed to develop and train four methods of MLAs, including the multi-layer perceptron (MLP) neural network, support vector regression (SVR), random forest, and adaptive boosting (AdaBoost). Inclination angle, mass velocity, vapor quality, and heat flux are used as input variables, while the corresponding heat transfer coefficient and pressure drop are considered as the output variables. According to the results obtained in the prediction of the heat transfer coefficient, AdaBoost model performs the best with the mean absolute percentage error (MAPE) of 5.73 % and correlation coefficient (R) of 0.979 on the test dataset. In the case of pressure drop prediction, MLP neural network shows the best performance with MAPE of 7.62 % and R of 0.990. In addition, the remarkable effect of using machine learning methods in improving prediction accuracy is demonstrated by comparing the results of MLAs with the predictions derived from some widely recognized empirical correlations.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101219"},"PeriodicalIF":0.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837833","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":"Impact of sinusoidal magnetic field on complex wave propagation in biomimetic peristaltic pumping of thixotropic and Newtonian fluids in an asymmetric channel","authors":"Asha Kotnurkar ,&nbsp;Santosh Gowda ,&nbsp;Mahadev Channakote","doi":"10.1016/j.ijft.2025.101215","DOIUrl":"10.1016/j.ijft.2025.101215","url":null,"abstract":"<div><div>This study presents a novel investigation into the peristaltic flow of shear-thinning thixotropic fluid within an asymmetric channel under a time-dependent sinusoidal magnetic field and buoyancy force, addressing a distinct research gap. The study incorporates the effects of chemical reactions and double diffusion within a porous medium while analyzing the heat transfer rate in a complex wavy channel. The momentum equations are modified to include sinusoidal magnetic forces, and the governing equations are simplified using the assumptions of a long wavelength and a very small Reynolds number. The intricate wave pattern at the channel walls is considered and the mathematical model is non-dimensionalized and solved by using the Homotopy Perturbation approach. Computational findings reveal that velocity decreases near the channel as the Hartmann number increases, whereas the Darcy number has the opposite effect. Temperature rises with increasing Dufour number and chemical reaction parameters, while concentration increases on the left side of the channel and decreases on the right as the Soret number grows. The velocity gradient is steeper for non-Newtonian fluids compared to Newtonian fluids, and higher Dufour numbers enhance the connection between mass and heat transfer. The sinusoidal magnetic field significantly influences non-Newtonian fluids, leading to enhanced velocity, temperature, and concentration profiles. Notably, the non-sinusoidal magnetic field exhibits advantages over its sinusoidal counterpart, generating 23 % more robust drag impact on fluid flow and a 113 % rise in temperature, indicating improved thermal energy transfer. This innovative mathematical model explores the unique behavior of thixotropic fluid under chemical processes and complex wave propagation, focusing on structural fluid parameters. The findings have potential applications in medical mechanisms, such as tailored drug delivery, and may aid in regulating pumping systems under sinusoidal magnetic forces.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101215"},"PeriodicalIF":0.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854443","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 exploration on n-decane nanofluid based MHD mixed convection in a lid driven cavity: impact of magnetic field and thermal radiation","authors":"Umme Habiba ,&nbsp;M.N. Hudha ,&nbsp;Badhan Neogi ,&nbsp;Saiful Islam ,&nbsp;M.M. Rahman","doi":"10.1016/j.ijft.2025.101209","DOIUrl":"10.1016/j.ijft.2025.101209","url":null,"abstract":"<div><div>Due to efficient heat transfer properties, nanofluids have become the core of research in the present world in the sectors of engineering, biotechnology, pharmaceutical industries, etc. The present work prioritizes the numerical assessment of n-decane/graphite nanofluid MHD mixed convective flow within a lid-driven trapezoidal barrier with radiation effect, where the left and right bottom, the side walls are kept thermally insulated, the upper wall (moving with uniform velocity, <em>u₀</em>) is in cold temperature (<em>T_c</em>) and a rectangular heater (with temperature, <em>T_h</em>) is placed in the middle of the bottom wall of the enclosure. The numerical executions of governing equations are conducted by finite element method. The resulting parameters, Hartmann number (<em>Ha</em> = 0, 30, 50 and 80), solid nanoparticle volume fraction (<em>ϕ</em> = 1 %, 5 %, 10 % and 15 %), radiation parameter (<em>Rd</em> = 0, 2, 3 and 4), Reynolds number (<em>Re</em> = 100, 200, 300 and 400) depict the result in terms of streamlines, isothermal contours, average Nusselt number (<em>Nu_av</em>), average velocity (<em>V_av</em>). It is noticed that the Hartmann number has a negative influence on fluid flow, which diminishes the vortex strength, average heat transfer rate and average velocity in all cases. In the present case, mixing additional solid nanoparticles in the base fluid augments the <em>Nu_av</em> that is being transferred from the source to the fluid, but it lessens the flow strength and average velocity. An increase in <em>Rd</em> elevates the streamline vortex strength and average velocity; in contrast, <em>Nu_av</em> is dropped by the Radiation parameter. The Reynolds number appears to have a positive impact on the overall phenomena as it gives rise to all the streamlined vortex strength, <em>Nu_av</em> and <em>V_av</em>. This study provides new insights into fluid flow characteristics and heat transfer enhancement in a hydrocarbon-based nanofluid system by combining the influence of thermal radiation and different magnetic field intensities in a distinctive manner. A new HVAC device can also be designed with this idea.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"27 ","pages":"Article 101209"},"PeriodicalIF":0.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143825769","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}