Pub Date : 2025-11-01DOI: 10.1016/j.ijft.2025.101501
Abdellah Idrissi , Elbachir Abddaim , Hicham El Mghari , Rachid El Amraoui , Siham Sakami , Lahcen Boukhattem
This study numerically investigates the effect of plate configurations on thermal stratification performance and energy efficiency of solar hot water storage tanks, emphasizing the role of plate configurations in enhancing energy efficiency. Using a detailed three-dimensional model comprising fluid flow and heat transfer equations, accompanied by Boussinesq approximation, the study analyzes the impact of plate size, placement, and inlet design on temperature distribution and thermocline behavior. Key performance indicators including the Richardson number (Ri), stratification number (St), pressure drop (ΔP), and discharging efficiency were assessed. Validation against experimental data confirmed the model's reliability, with discrepancies remaining below 5 %. The obtained results showed that the perforated plates with 25 % open area achieved the highest Ri (55.36), the lowest ΔP (6.68 Pa), and pumping energy (0.178 μW), along with the most efficient stratification performance. In contrast, solid plates provided balanced stratification with Ri values of 4.79 and moderate ΔP of about 7.84 Pa. The outcomes confirm that plate diameter, placement near the thermocline, and perforation design significantly impact thermal stratification and energy efficiency, offering critical insights for optimizing thermal energy storage in renewable energy systems.
{"title":"Effect of plate configurations on thermal stratification and energy efficiency in solar hot water storage tanks: A CFD-based analysis","authors":"Abdellah Idrissi , Elbachir Abddaim , Hicham El Mghari , Rachid El Amraoui , Siham Sakami , Lahcen Boukhattem","doi":"10.1016/j.ijft.2025.101501","DOIUrl":"10.1016/j.ijft.2025.101501","url":null,"abstract":"<div><div>This study numerically investigates the effect of plate configurations on thermal stratification performance and energy efficiency of solar hot water storage tanks, emphasizing the role of plate configurations in enhancing energy efficiency. Using a detailed three-dimensional model comprising fluid flow and heat transfer equations, accompanied by Boussinesq approximation, the study analyzes the impact of plate size, placement, and inlet design on temperature distribution and thermocline behavior. Key performance indicators including the Richardson number (Ri), stratification number (St), pressure drop (ΔP), and discharging efficiency were assessed. Validation against experimental data confirmed the model's reliability, with discrepancies remaining below 5 %. The obtained results showed that the perforated plates with 25 % open area achieved the highest Ri (55.36), the lowest ΔP (6.68 Pa), and pumping energy (0.178 μW), along with the most efficient stratification performance. In contrast, solid plates provided balanced stratification with Ri values of 4.79 and moderate ΔP of about 7.84 Pa. The outcomes confirm that plate diameter, placement near the thermocline, and perforation design significantly impact thermal stratification and energy efficiency, offering critical insights for optimizing thermal energy storage in renewable energy systems.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101501"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614334","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}
Pub Date : 2025-11-01DOI: 10.1016/j.ijft.2025.101505
Ammar Alkhalidi , Abdulnaser Bdiwi , Mohamad K. Khawaja
Wind speeds, high or low, have a detrimental effect on the rated turbine’s rotational speed in wind energy systems. This study proposes an electromagnetic torque modulation enhancement system that consists of a brushless motor mounted on the turbine’s shaft to enhance the rotational speed by generating a magnetic field. This enhancement raises and lowers the rotational speed of the wind turbine blades as needed. For testing, a horizontal wind turbine consisting of a micro-generator connected to 820 mm rotor diameter was used, with a rated power of 8 W, and it was installed at 700 mm above ground. The enhancement system was evaluated under four different scenarios. Results showed that when the enhancement system decreased the rotational speed, it was able to recover a large portion of the energy that would have been curtailed in the case of cut-out speed and lost only 5.7% of the energy compared to 100% if the wind turbine was shut down due to overspeed. However, when the enhancement system increased the rotational speed or maintained it at a range of 500–750 RPM, it improved by 1%.
{"title":"Experimental investigation of an enhancement system to improve wind turbines power generation","authors":"Ammar Alkhalidi , Abdulnaser Bdiwi , Mohamad K. Khawaja","doi":"10.1016/j.ijft.2025.101505","DOIUrl":"10.1016/j.ijft.2025.101505","url":null,"abstract":"<div><div>Wind speeds, high or low, have a detrimental effect on the rated turbine’s rotational speed in wind energy systems. This study proposes an electromagnetic torque modulation enhancement system that consists of a brushless motor mounted on the turbine’s shaft to enhance the rotational speed by generating a magnetic field. This enhancement raises and lowers the rotational speed of the wind turbine blades as needed. For testing, a horizontal wind turbine consisting of a micro-generator connected to 820 mm rotor diameter was used, with a rated power of 8 W, and it was installed at 700 mm above ground. The enhancement system was evaluated under four different scenarios. Results showed that when the enhancement system decreased the rotational speed, it was able to recover a large portion of the energy that would have been curtailed in the case of cut-out speed and lost only 5.7% of the energy compared to 100% if the wind turbine was shut down due to overspeed. However, when the enhancement system increased the rotational speed or maintained it at a range of 500–750 RPM, it improved by 1%.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101505"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614332","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}
Pub Date : 2025-11-01DOI: 10.1016/j.ijft.2025.101504
Reza Kaviani, Iman Ghamarian, Hamidreza Shabgard, Pejman Kazempoor
Close-contact melting is a multiphase multiscale phenomenon that occurs during unconstrained melting of phase change materials (PCM) in a heated capsule and is characterized by the formation of a liquid film between the sinking/rising solid PCM and the heated wall. This research investigates the utilization of the artificial neural network (ANN) to predict the melting rate of PCM with and without nano-additives during the close-contact melting process within a spherical capsule. The main parameters controlling the close-contact melting process, namely the capsule size, the heated wall temperature, and the thermophysical properties of the PCM, are accounted for in the ANN model through the introduction of six dimensionless groups: Fourier (Fo), Stefan (Ste), Grashof (Gr), Galileo (Ga), Archimedes (Ar), and Prandtl (Pr). To train the neural network, a comprehensive dataset comprising over 1000 data points from 50 different experimental studies reported in the literature was employed. The ANN model proved successful in predicting the quantitative and qualitative influence of the control parameters. Most notably, it was found that the PCM melting rate accelerates by increasing Ste, Gr, Ga, and Ar numbers, and by decreasing Pr number, however, the extent of their respective impacts varies significantly. This work demonstrates the usefulness of ANN for the analysis of problems that are challenging to simulate using traditional computational methods due to the presence of fluid-solid interactions and multiphase multiscale features such as melting and thin liquid film formation.
{"title":"Artificial neural network prediction of unconstrained close-contact melting of phase change materials within spherical capsules","authors":"Reza Kaviani, Iman Ghamarian, Hamidreza Shabgard, Pejman Kazempoor","doi":"10.1016/j.ijft.2025.101504","DOIUrl":"10.1016/j.ijft.2025.101504","url":null,"abstract":"<div><div>Close-contact melting is a multiphase multiscale phenomenon that occurs during unconstrained melting of phase change materials (PCM) in a heated capsule and is characterized by the formation of a liquid film between the sinking/rising solid PCM and the heated wall. This research investigates the utilization of the artificial neural network (ANN) to predict the melting rate of PCM with and without nano-additives during the close-contact melting process within a spherical capsule. The main parameters controlling the close-contact melting process, namely the capsule size, the heated wall temperature, and the thermophysical properties of the PCM, are accounted for in the ANN model through the introduction of six dimensionless groups: Fourier (Fo), Stefan (Ste), Grashof (Gr), Galileo (Ga), Archimedes (Ar), and Prandtl (Pr). To train the neural network, a comprehensive dataset comprising over 1000 data points from 50 different experimental studies reported in the literature was employed. The ANN model proved successful in predicting the quantitative and qualitative influence of the control parameters. Most notably, it was found that the PCM melting rate accelerates by increasing Ste, Gr, Ga, and Ar numbers, and by decreasing Pr number, however, the extent of their respective impacts varies significantly. This work demonstrates the usefulness of ANN for the analysis of problems that are challenging to simulate using traditional computational methods due to the presence of fluid-solid interactions and multiphase multiscale features such as melting and thin liquid film formation.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101504"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681093","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}
Pub Date : 2025-11-01DOI: 10.1016/j.ijft.2025.101512
Muhammad Ahmad, Mohammad O. Hamdan, Bassam A. Abu-Nabah
The current study numerically investigates the thermal performance and optimization of metal foam (MF) heat sinks for electronic cooling applications. Key design parameters include different types of phase change material (PCM) (RT31, RT42, RT55), MF porosity (0.1–95 %), MF material (aluminum, copper, stainless steel), MF permeability (10–8–10–12), and heat flux levels (1000–8000 W/m2). The simulations, conducted using ANSYS Fluent, optimize a plate-fin heat sink based on a critical temperature of 80 °C while incorporating the Boussinesq approximation for buoyancy effects. Results suggest that high-porosity metal foam enhances heat dissipation by increasing the effective thermal conductivity of the PCM-metal foam system, which accelerates PCM melting and solidification, reduces base-surface temperature, and improves overall thermal management. RT55’s higher melting point extends solid-state heat absorption by 23.5 min versus RT31 and 16.3 min versus RT42 for aluminum foam with 95 % porosity at 2000 W/m2. The effects of permeability and gravity are negligible in the presence of metal foam. The optimal configuration is RT55 infused with 95 % porous copper foam, maximizing thermal energy storage. Additionally, higher porosity increases melting time due to the larger PCM volume, while PCM selection significantly impacts thermal efficiency. Heat sink size also influences foam material effectiveness, affecting heat transfer and fluid flow dynamics.
{"title":"Enhanced electronic cooling with optimized metal foam/PCM composite heat sinks: A numerical study","authors":"Muhammad Ahmad, Mohammad O. Hamdan, Bassam A. Abu-Nabah","doi":"10.1016/j.ijft.2025.101512","DOIUrl":"10.1016/j.ijft.2025.101512","url":null,"abstract":"<div><div>The current study numerically investigates the thermal performance and optimization of metal foam (MF) heat sinks for electronic cooling applications. Key design parameters include different types of phase change material (PCM) (RT31, RT42, RT55), MF porosity (0.1–95 %), MF material (aluminum, copper, stainless steel), MF permeability (10<sup>–8</sup>–10<sup>–12</sup>), and heat flux levels (1000–8000 W/m<sup>2</sup>). The simulations, conducted using ANSYS Fluent, optimize a plate-fin heat sink based on a critical temperature of 80 °C while incorporating the Boussinesq approximation for buoyancy effects. Results suggest that high-porosity metal foam enhances heat dissipation by increasing the effective thermal conductivity of the PCM-metal foam system, which accelerates PCM melting and solidification, reduces base-surface temperature, and improves overall thermal management. RT55’s higher melting point extends solid-state heat absorption by 23.5 min versus RT31 and 16.3 min versus RT42 for aluminum foam with 95 % porosity at 2000 W/m<sup>2</sup>. The effects of permeability and gravity are negligible in the presence of metal foam. The optimal configuration is RT55 infused with 95 % porous copper foam, maximizing thermal energy storage. Additionally, higher porosity increases melting time due to the larger PCM volume, while PCM selection significantly impacts thermal efficiency. Heat sink size also influences foam material effectiveness, affecting heat transfer and fluid flow dynamics.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101512"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681094","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}
Pub Date : 2025-10-21DOI: 10.1016/j.ijft.2025.101457
Pareekshith G. Bhat , Ali J. Chamkha , Nityanand P. Pai , Likhitha Nayak , Sampath Kumar V.S. , Devaki B. , Akshay Kumar , Ashwin Kumar Devaraj
The present study aims to theoretically investigate the impact of viscous dissipation on the behavior of heat transfer in the flow of ethylene glycol (EG)-based Graphene–Copper hybrid nanofluid (HNF). Furthermore, the nanofluid is assumed to be flowing through a channel of squeezing parallel disks under the combined effects of thermal radiation and external magnetic field. Moreover, it is considered that the impermeable upper disk approaches and dilates from the stationary lower porous disk through which the injection or suction takes place. The non-linear conservation equations that govern the flow and heat are translated into non-linear ordinary differential equations (ODEs) using suitable similarity transformations. Further, the obtained ODEs are approached by an elegant semi-analytical technique, the Homotopy perturbation method, in order to attain an approximate solution. In addition to the semi-analytical solution, the considered model is approached by the 4th order Runge–Kutta method, a well-known numerical technique, in order to compare the solutions obtained by two independent techniques. This investigation mainly highlights on analyzing the velocity distribution profile, coefficient of skin friction, temperature field, and Nusselt number for distinct pertinent physical parameters. From the figures, it is derived that the temperature profile rises with an increment in the Eckert number. However, it is noticed that a rise in the radiation parameter results in the temperature distribution to retard as the disks dilate in the suction case. Furthermore, it is perceived from the tables that the magnitude of the Nusselt number increases with elevation in the radiation parameter. Moreover, it can be concluded from the results that the solutions obtained from the two techniques are in good harmony.
{"title":"Thermally radiated heat transfer analysis on the viscous dissipated MHD EG-based copper-graphene hybrid nanofluid flow between parallel disks","authors":"Pareekshith G. Bhat , Ali J. Chamkha , Nityanand P. Pai , Likhitha Nayak , Sampath Kumar V.S. , Devaki B. , Akshay Kumar , Ashwin Kumar Devaraj","doi":"10.1016/j.ijft.2025.101457","DOIUrl":"10.1016/j.ijft.2025.101457","url":null,"abstract":"<div><div>The present study aims to theoretically investigate the impact of viscous dissipation on the behavior of heat transfer in the flow of ethylene glycol (EG)-based Graphene–Copper hybrid nanofluid (HNF). Furthermore, the nanofluid is assumed to be flowing through a channel of squeezing parallel disks under the combined effects of thermal radiation and external magnetic field. Moreover, it is considered that the impermeable upper disk approaches and dilates from the stationary lower porous disk through which the injection or suction takes place. The non-linear conservation equations that govern the flow and heat are translated into non-linear ordinary differential equations (ODEs) using suitable similarity transformations. Further, the obtained ODEs are approached by an elegant semi-analytical technique, the Homotopy perturbation method, in order to attain an approximate solution. In addition to the semi-analytical solution, the considered model is approached by the 4th order Runge–Kutta method, a well-known numerical technique, in order to compare the solutions obtained by two independent techniques. This investigation mainly highlights on analyzing the velocity distribution profile, coefficient of skin friction, temperature field, and Nusselt number for distinct pertinent physical parameters. From the figures, it is derived that the temperature profile rises with an increment in the Eckert number. However, it is noticed that a rise in the radiation parameter results in the temperature distribution to retard as the disks dilate in the suction case. Furthermore, it is perceived from the tables that the magnitude of the Nusselt number increases with elevation in the radiation parameter. Moreover, it can be concluded from the results that the solutions obtained from the two techniques are in good harmony.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101457"},"PeriodicalIF":0.0,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362998","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}
Pub Date : 2025-10-16DOI: 10.1016/j.ijft.2025.101451
Muhammad Ehsan Ullah , Syed Tauseef Saeed , Najla A. Mohammed , Muhammad Idress , Muhammad Nauman Aslam , Ilyas Khan , Osama Oqilat , Muhammad Sabaoon Khan
This comprehensive numerical study of three-dimensional Prandtl ternary ferrofluid flow over a stretching surface considers the combined effects of Darcy–Forchheimer drag, activation energy, thermal radiation, Brownian motion, thermophoresis, heat generation/absorption, porous media, mass diffusivity, and magnetohydrodynamics (MHD). Ferrofluid is created by dispersing copper (Cu), iron oxide (), and cobalt ferrite () nanoparticles in a water-based Prandtl fluid in order to enhance thermal conductivity and magnetic permeability. The model includes radiative and non-Fourier heat conduction for realistic thermal representation, while the Darcy–Forchheimer approach characterises linear and nonlinear resistance in porous structures. Convective boundary conditions are used to replicate realistic heat exchange at the surface.
The governing partial differential equations of mass, momentum, energy, and species concentration are reduced by similarity transformations into a system of nonlinear ordinary differential equations. For computational accuracy, the shooting technique is employed to numerically solve these equations. The study looks at the parametric impacts of radiation, heat source/sink, Schmidt number, activated energy, magnetic field strength, porosity, Forchheimer number, Brownian motion, and thermophoresis. In addition to assessments of skin friction, Nusselt number, and Sherwood number, the distributions of temperature, velocity, and concentration are examined using tabular and graphical results.
The results show that thermal radiation and thermophoresis improve thermal dispersion, but greater porosity and magnetic intensity reduce velocity because of greater resistance. Because of finite mass diffusivity, concentration falls with increasing Schmidt numbers and activation energy. For engineering systems incorporating magnetic nanofluids and porous media, this work offers insightful information on transport phenomena. These systems have applications in materials processing, thermal management, and biomedical engineering.
{"title":"Prandtl ternary nanofluid flow with MHD, Porosity, and thermal effects over a 3D stretching surface with convective boundary conditions","authors":"Muhammad Ehsan Ullah , Syed Tauseef Saeed , Najla A. Mohammed , Muhammad Idress , Muhammad Nauman Aslam , Ilyas Khan , Osama Oqilat , Muhammad Sabaoon Khan","doi":"10.1016/j.ijft.2025.101451","DOIUrl":"10.1016/j.ijft.2025.101451","url":null,"abstract":"<div><div>This comprehensive numerical study of three-dimensional Prandtl ternary ferrofluid flow over a stretching surface considers the combined effects of Darcy–Forchheimer drag, activation energy, thermal radiation, Brownian motion, thermophoresis, heat generation/absorption, porous media, mass diffusivity, and magnetohydrodynamics (MHD). Ferrofluid is created by dispersing copper (Cu), iron oxide (<span><math><mrow><mi>F</mi><msub><mrow><mi>e</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>), and cobalt ferrite (<span><math><mrow><mi>C</mi><mi>o</mi><mi>F</mi><msub><mrow><mi>e</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>) nanoparticles in a water-based Prandtl fluid in order to enhance thermal conductivity and magnetic permeability. The model includes radiative and non-Fourier heat conduction for realistic thermal representation, while the Darcy–Forchheimer approach characterises linear and nonlinear resistance in porous structures. Convective boundary conditions are used to replicate realistic heat exchange at the surface.</div><div>The governing partial differential equations of mass, momentum, energy, and species concentration are reduced by similarity transformations into a system of nonlinear ordinary differential equations. For computational accuracy, the shooting technique is employed to numerically solve these equations. The study looks at the parametric impacts of radiation, heat source/sink, Schmidt number, activated energy, magnetic field strength, porosity, Forchheimer number, Brownian motion, and thermophoresis. In addition to assessments of skin friction, Nusselt number, and Sherwood number, the distributions of temperature, velocity, and concentration are examined using tabular and graphical results.</div><div>The results show that thermal radiation and thermophoresis improve thermal dispersion, but greater porosity and magnetic intensity reduce velocity because of greater resistance. Because of finite mass diffusivity, concentration falls with increasing Schmidt numbers and activation energy. For engineering systems incorporating magnetic nanofluids and porous media, this work offers insightful information on transport phenomena. These systems have applications in materials processing, thermal management, and biomedical engineering.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101451"},"PeriodicalIF":0.0,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363000","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}
In this research is investigated flow of hybrid nanofluid of the Al2O3 and CuO based on water fluid and electromagnetic force between parallel plates with a heat source. In this model effect of Brownian motion on the effective thermal conductivity also is considered. The innovation in the present paper is that the meshless method of the radial basis function (RBF) for is used for governing equationsthe desired geometry. In this method, without using pre-determined meshing to discretize the domain, it turns the problem into a system of algebraic equations by only using the set of scattered points in the domain and its boundaries. The ability of the RBF method is shown in comparing it with the numerical method finite element method (FEM) to solve this problem, which is in good agreement. In order to evaluate the convergence analysis of the method, error estimations are made by a residual function denoted. The results represent that the vertical velocity of the hybrid nanofluid in is increased compared to the vertical velocity of the mono nanofluid, but in is not a significant difference in velocity. Furthermore, the thickness of the thermal boundary layer of the hybrid nanofluid decreases. Also, the horizontal velocity of the hybrid nanofluid decreases with the increase of squeeze number untile but for the results are the opposite which leads to the formation of the backflow phenomenon. Moreover, the velocity components of the hybrid nanofluid remain unaffected by an increasing heat source parameter while increasing the thermal boundary layer thickness.
{"title":"Investigating the MHD flow of hybrid nanofluid Al2O3 - CuO with brownian motion between two parallel plates using RBF","authors":"Elham Tayari , Leila Torkzadeh , Davood Domiri Ganji , Kazem Nouri","doi":"10.1016/j.ijft.2025.101458","DOIUrl":"10.1016/j.ijft.2025.101458","url":null,"abstract":"<div><div>In this research is investigated flow of hybrid nanofluid of the Al<sub>2</sub>O<sub>3</sub> and CuO based on water fluid and electromagnetic force between parallel plates with a heat source. In this model effect of Brownian motion on the effective thermal conductivity also is considered. The innovation in the present paper is that the meshless method of the radial basis function (RBF) for is used for governing equationsthe desired geometry. In this method, without using pre-determined meshing to discretize the domain, it turns the problem into a system of algebraic equations by only using the set of scattered points in the domain and its boundaries. The ability of the RBF method is shown in comparing it with the numerical method finite element method (FEM) to solve this problem, which is in good agreement. In order to evaluate the convergence analysis of the method, error estimations are made by a residual function denoted. The results represent that the vertical velocity of the hybrid nanofluid in <span><math><mrow><mi>Ha</mi><mo>=</mo><mn>0</mn></mrow></math></span> is increased compared to the vertical velocity of the mono nanofluid, but in <span><math><mrow><mi>Ha</mi><mo>=</mo><mn>8</mn></mrow></math></span> is not a significant difference in velocity. Furthermore, the thickness of the thermal boundary layer of the hybrid nanofluid decreases. Also, the horizontal velocity of the hybrid nanofluid decreases with the increase of squeeze number untile <span><math><mrow><mi>η</mi><mo><</mo><mn>0.5</mn></mrow></math></span> but for <span><math><mrow><mi>η</mi><mo>></mo><mn>0.5</mn></mrow></math></span> the results are the opposite which leads to the formation of the backflow phenomenon. Moreover, the velocity components of the hybrid nanofluid remain unaffected by an increasing heat source parameter while increasing the thermal boundary layer thickness.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101458"},"PeriodicalIF":0.0,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362467","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}
Pub Date : 2025-10-15DOI: 10.1016/j.ijft.2025.101455
A G Thimmaiah , Sadananda Megeri , Banjara Kotresha , M Muniraju , T C Shubha , Suresh Kote , K P Jhansilakshmi , Shashikumar C M
The work presents the exergy analysis of discrete/baffle metal foam filled in an asymmetrical heated channel using 2nd law of thermodynamics. The metal foam heat exchangers are deliberated as promising candidate for augmenting the heat transfer rate in numerous thermal applications, especially like electronics cooling, and etc. The objective of the analysis is to find the optimum discrete/baffle metal foam configuration that gives the superlative hydrothermal outcomes. Hence, the main aim of the investigation is to obtain the best suitable discrete/baffle metal foam combination among two, three, four and five discrete/baffles configurations positioned at various locations in the test section. For this purpose, the province taken up for the analysis comprises a horizontal channel in which an integrated heater cum aluminium plate assembly is positioned on the top wall. A constant heat input is assigned to the heater and the water coolant flowing through the channel takes away the heat generated inside the aluminium plate. The heat transfer through the channel is increased by using various discrete/baffle metal foam filling combinations. A combined DEF (Darcy Extended Forchheimer) along with LTE (Local Thermal Equilibrium) popular models are considered for envisaging the flow and heat transfer characteristics through the metal foam. The adopted procedure in the current work is initially authenticated using literature results. The upshots confirms that the discrete/baffle metal foam is best suited for enhancing the thermal properties compared to clear channel as well as fully filled metal foam channel. Among the various configuration studied the five discrete/baffle metal foam configuration gives the higher thermal improvement likened to other two, three and four metal foam configurations. The five discrete/baffle metal foam stretches approximately 74.27 % heat transfer likened with completely filled metal foam channel with nearly 50 % reduced pressure. It is evaluated from Colburn j factor that two, three, four and five discrete/baffle configuration gives an average of 167.04 %, 312.71 %, 315.54 % and 384.35 % increase in thermal performance respectively compared to clear channel. The working limits permitted by exergy (WLPE) is estimated based on exergy results for the selected configurations and found that the WLPE for 1-3 (two), 3-4-5 (three), 2-3-4-5 (four) and 1-2-3-4-5 (five) discrete/baffle metal foams configurations are 5024.96, 4182.93, 4169.14 and 3902.75 respectively. The exergy results also proves the selection of best optimum configuration.
{"title":"Forced convection and exergy analysis of discrete metal foams filled in a channel","authors":"A G Thimmaiah , Sadananda Megeri , Banjara Kotresha , M Muniraju , T C Shubha , Suresh Kote , K P Jhansilakshmi , Shashikumar C M","doi":"10.1016/j.ijft.2025.101455","DOIUrl":"10.1016/j.ijft.2025.101455","url":null,"abstract":"<div><div>The work presents the exergy analysis of discrete/baffle metal foam filled in an asymmetrical heated channel using 2<sup>nd</sup> law of thermodynamics. The metal foam heat exchangers are deliberated as promising candidate for augmenting the heat transfer rate in numerous thermal applications, especially like electronics cooling, and etc. The objective of the analysis is to find the optimum discrete/baffle metal foam configuration that gives the superlative hydrothermal outcomes. Hence, the main aim of the investigation is to obtain the best suitable discrete/baffle metal foam combination among two, three, four and five discrete/baffles configurations positioned at various locations in the test section. For this purpose, the province taken up for the analysis comprises a horizontal channel in which an integrated heater cum aluminium plate assembly is positioned on the top wall. A constant heat input is assigned to the heater and the water coolant flowing through the channel takes away the heat generated inside the aluminium plate. The heat transfer through the channel is increased by using various discrete/baffle metal foam filling combinations. A combined DEF (Darcy Extended Forchheimer) along with LTE (Local Thermal Equilibrium) popular models are considered for envisaging the flow and heat transfer characteristics through the metal foam. The adopted procedure in the current work is initially authenticated using literature results. The upshots confirms that the discrete/baffle metal foam is best suited for enhancing the thermal properties compared to clear channel as well as fully filled metal foam channel. Among the various configuration studied the five discrete/baffle metal foam configuration gives the higher thermal improvement likened to other two, three and four metal foam configurations. The five discrete/baffle metal foam stretches approximately 74.27 % heat transfer likened with completely filled metal foam channel with nearly 50 % reduced pressure. It is evaluated from Colburn j factor that two, three, four and five discrete/baffle configuration gives an average of 167.04 %, 312.71 %, 315.54 % and 384.35 % increase in thermal performance respectively compared to clear channel. The working limits permitted by exergy (WLPE) is estimated based on exergy results for the selected configurations and found that the WLPE for 1-3 (two), 3-4-5 (three), 2-3-4-5 (four) and 1-2-3-4-5 (five) discrete/baffle metal foams configurations are 5024.96, 4182.93, 4169.14 and 3902.75 respectively. The exergy results also proves the selection of best optimum configuration.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101455"},"PeriodicalIF":0.0,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363001","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}
Pub Date : 2025-10-14DOI: 10.1016/j.ijft.2025.101454
M. Al-Amin , T. Islam , M. Shihab , A.K. Azad , A. Paul , M.M. Rahman , M.F. Karim
Double-diffusive mixed convection in lid-driven cavities has been widely studied. However, the use of Al₂O₃–Cu/H₂O hybrid nanofluids in H-shaped enclosures are crucial for compact heat exchangers and micro-cooling systems which remains largely unexplored despite their superior thermal and convective properties. Moreover, the sensitivity of governing input parameters, a critical aspect for optimizing thermal-fluid performance has not been systematically addressed in previous studies. To address the gaps, this study focuses on the sensitivity analysis of mixed convection heat and mass transfer within a lid-driven H-shaped cavity, filled with hybrid nanofluid and featuring partially heated and concentrated walls. The primary objective is to study the influence of key dimensionless factors Ri, Re, and Le on the thermal and mass transfer performance of the system. A statistical method using response surface methodology (RSM) was implemented, with numerical simulations based on the Galerkin weighted residual FEM to solve the governing partial differential equations. The findings demonstrate that both the average heat transfer rate (Nu) and the average mass transfer rate (Sh) show a positive sensitivity to Ri and Re, however an inverse correlation was noted with Le. Furthermore, the sensitivity analysis indicates that Nu increases with the rise in Ri and Re but decreases with Le, while Sh increases with all three factors. The average heat transfer rate indicates a 12.02 % increase as the nanoparticle volume fraction (ϕ) increases from 1 % to 4 %, while a decrease of 11.25 % is noted when Le rises from 0.01 to 5. The statistical assessment of the model shows high R² values (98.52 % for Nu and 95.13 % for Sh), confirming the model’s suitability for forecasting these response functions. This study offers significant insights for optimizing heat and mass transfer processes in hybrid nanofluid applications.
{"title":"Double-diffusive optimization in hybrid nanofluid convection using response surface method","authors":"M. Al-Amin , T. Islam , M. Shihab , A.K. Azad , A. Paul , M.M. Rahman , M.F. Karim","doi":"10.1016/j.ijft.2025.101454","DOIUrl":"10.1016/j.ijft.2025.101454","url":null,"abstract":"<div><div>Double-diffusive mixed convection in lid-driven cavities has been widely studied. However, the use of Al₂O₃–Cu/H₂O hybrid nanofluids in H-shaped enclosures are crucial for compact heat exchangers and micro-cooling systems which remains largely unexplored despite their superior thermal and convective properties. Moreover, the sensitivity of governing input parameters, a critical aspect for optimizing thermal-fluid performance has not been systematically addressed in previous studies. To address the gaps, this study focuses on the sensitivity analysis of mixed convection heat and mass transfer within a lid-driven H-shaped cavity, filled with hybrid nanofluid and featuring partially heated and concentrated walls. The primary objective is to study the influence of key dimensionless factors <em>Ri, Re</em>, and <em>Le</em> on the thermal and mass transfer performance of the system. A statistical method using response surface methodology (RSM) was implemented, with numerical simulations based on the Galerkin weighted residual FEM to solve the governing partial differential equations. The findings demonstrate that both the average heat transfer rate (<em>Nu</em>) and the average mass transfer rate (<em>Sh</em>) show a positive sensitivity to <em>Ri</em> and <em>Re</em>, however an inverse correlation was noted with <em>Le</em>. Furthermore, the sensitivity analysis indicates that <em>Nu</em> increases with the rise in <em>Ri</em> and <em>Re</em> but decreases with <em>Le</em>, while <em>Sh</em> increases with all three factors. The average heat transfer rate indicates a 12.02 % increase as the nanoparticle volume fraction (<em>ϕ</em>) increases from 1 % to 4 %, while a decrease of 11.25 % is noted when <em>Le</em> rises from 0.01 to 5. The statistical assessment of the model shows high <em>R</em>² values (98.52 % for <em>Nu</em> and 95.13 % for <em>Sh</em>), confirming the model’s suitability for forecasting these response functions. This study offers significant insights for optimizing heat and mass transfer processes in hybrid nanofluid applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101454"},"PeriodicalIF":0.0,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362466","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}
Pub Date : 2025-10-13DOI: 10.1016/j.ijft.2025.101448
Mahmmoud M. Syam , Al Reem Alameri , Rahmah Al Qatbi , Mays Haddad , Muhammed I. Syam , Anas Mustafa
This study investigates the unsteady squeezing flow and heat transfer behavior of a graphene oxide–water nanofluid confined between two parallel plates. The research is motivated by the need to enhance thermal transport in micro- and nanoscale systems, where precise control of fluid flow and heat dissipation is critical. A time-dependent mathematical model is developed under the assumptions of incompressible, laminar and single-phase nanofluid flow, incorporating viscous dissipation and nanoparticle effects. Through similarity transformations, the governing partial differential equations are reduced to a system of nonlinear boundary value problems, which are then solved using a modified operational matrix method. The results demonstrate that the nanoparticle volume fraction, Prandtl number, Eckert number and squeezing parameter have a strong influence on the velocity and temperature fields. Validation through truncation error analysis, boundary condition checks and comparison with published Nusselt number data confirms the reliability of the proposed approach. The findings highlight the potential of graphene oxide nanofluids to significantly enhance heat transfer performance under dynamic squeezing conditions, offering promising benefits for applications in lubrication systems, microelectromechanical devices and advanced thermal management technologies.
{"title":"Heat transfer characteristics of graphene oxide nanofluid in unsteady squeezing flow between plates","authors":"Mahmmoud M. Syam , Al Reem Alameri , Rahmah Al Qatbi , Mays Haddad , Muhammed I. Syam , Anas Mustafa","doi":"10.1016/j.ijft.2025.101448","DOIUrl":"10.1016/j.ijft.2025.101448","url":null,"abstract":"<div><div>This study investigates the unsteady squeezing flow and heat transfer behavior of a graphene oxide–water nanofluid confined between two parallel plates. The research is motivated by the need to enhance thermal transport in micro- and nanoscale systems, where precise control of fluid flow and heat dissipation is critical. A time-dependent mathematical model is developed under the assumptions of incompressible, laminar and single-phase nanofluid flow, incorporating viscous dissipation and nanoparticle effects. Through similarity transformations, the governing partial differential equations are reduced to a system of nonlinear boundary value problems, which are then solved using a modified operational matrix method. The results demonstrate that the nanoparticle volume fraction, Prandtl number, Eckert number and squeezing parameter have a strong influence on the velocity and temperature fields. Validation through truncation error analysis, boundary condition checks and comparison with published Nusselt number data confirms the reliability of the proposed approach. The findings highlight the potential of graphene oxide nanofluids to significantly enhance heat transfer performance under dynamic squeezing conditions, offering promising benefits for applications in lubrication systems, microelectromechanical devices and advanced thermal management technologies.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101448"},"PeriodicalIF":0.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321219","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}
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