International Journal of Thermofluids最新文献

{"title":"MHD Casson Nanofluid Flow over a Stretching Rotating Disk with Heat Source and Spatially Varying Magnetic Field","authors":"Talha Anwar ,&nbsp;Qadeer Raza ,&nbsp;Tahir Mushtaq ,&nbsp;Bagh Ali ,&nbsp;Ehsanullah Hemati","doi":"10.1016/j.ijft.2025.101422","DOIUrl":"10.1016/j.ijft.2025.101422","url":null,"abstract":"<div><div>This paper investigates the steady magnetohydrodynamic (MHD) flow and heat transfer of a Casson nanofluid over a stretching, rotating disk in the presence of a spatially varying magnetic field and internal heat source. The model incorporates the Buongiorno nanofluid framework, which accounts for nanoparticle motion due to Brownian diffusion and thermophoresis, and includes velocity, thermal, and concentration slip conditions at the disk surface. Unlike traditional studies assuming a uniform magnetic field, the present work considers a magnetic field that decays exponentially away from the disk surface, providing a more realistic representation of applied magnetic fields in practical systems such as electromagnetic processing and rotating machinery. Additionally, the influence of an internal heat generation term is included in the energy equation to simulate thermal sources within the fluid. By applying similarity transformations, the governing nonlinear partial differential equations are reduced to a system of coupled ordinary differential equations. These equations are solved numerically using the bvp4c function in the Matlab computer language. The effects of various physical parameters such as magnetic field strength and gradient, slip coefficients, Casson fluid parameter, and heat source intensity are systematically explored. The results reveal that increasing the magnetic field strength or the heat source significantly enhances the thermal boundary layer, while velocity profiles are suppressed near the disk due to magnetic damping. The presence of multiple slips and the Casson fluid parameter further alter the flow and thermal behavior, making the system tunable for thermal management applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101422"},"PeriodicalIF":0.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221918","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":"Multi discharge assessment of non-eutectic mixture PCM as excellent candidate for medium temperature thermal storage operation","authors":"Joko Waluyo ,&nbsp;Sugeng Priyanto ,&nbsp;Robertus Dhimas Dhewangga Putra ,&nbsp;Reza Abdu Rahman","doi":"10.1016/j.ijft.2025.101423","DOIUrl":"10.1016/j.ijft.2025.101423","url":null,"abstract":"<div><div>Mixing polyol-based phase change material (P-PCM) to form non-eutectic mixture (NEM) is performed to reduce the impact of poor crystallization of sorbitol (STL) and high supercooling of mannitol (MTL). A series of experimental evaluations is designed based on various discharge methods commonly used for the application of thermal energy storage (TES) systems. It is the main novelty of this work, as the modification of the TES material is evaluated under different discharge methods, providing more detailed outcomes to understand the impact of material modification and operational conditions on the performance of the TES system. The finding indicates the charging capacity for the produced NEM varies between 430.8 – 486.1 Wh, which is higher than STL (386.2 Wh). Forming NEM with 25 wt% MTL offers a reliable rating charge, which enhances 10.1% than MTL. Active discharge with air yields the highest rating at 1.29°C/min for NEM, which improves under passive operation with liquid by 43.7% relative to STL. Improvement on the solidification mechanism indicates positive outcome according to the average increment of water temperature outlet with maximum improvement around 13.1°C. Rapid discharge by flowing water through the external wall of TES container produces a higher temperature outlet, which improves between 18.5 - 21.3°C. Detailed observation of the heat release profile demonstrates a significant impact on the solidification behavior, implying that the formation of NEM has a better freezing mechanism than the base material. The finding opens up new opportunities to use NEM as a reliable solution to improve the usability of P-PCM for TES systems.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101423"},"PeriodicalIF":0.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119555","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":"Influence of chemical reaction on convective flow in porous medium with varying viscosity generated by internal heat source in thermal non-equilibrium temperature conditions","authors":"Monal Bharty ,&nbsp;Atul K. Srivastava ,&nbsp;Hrishikesh Mahato ,&nbsp;Ashwini Kumar ,&nbsp;Mayank Srivastava ,&nbsp;Jayant Giri ,&nbsp;Eman Ramadan Elsharkawy ,&nbsp;Divya Srivastava","doi":"10.1016/j.ijft.2025.101412","DOIUrl":"10.1016/j.ijft.2025.101412","url":null,"abstract":"<div><div>This study investigates the onset of natural convection in a horizontal fluid-saturated porous medium subject to uniform internal heat generation and chemical reactions under local thermal non-equilibrium (LTNE) temperature conditions. The fluid viscosity is assumed to vary nonlinearly with temperature, capturing realistic thermophysical behavior often encountered in high-temperature and chemically reactive porous systems. Such configurations are frequently encountered in engineering applications, including geothermal energy extraction, thermal insulation in buildings, chemical catalytic reactors, nuclear waste disposal, and porous heat exchangers. In these systems, internal heat generation, chemical reactions, and non-equilibrium heat exchange between fluid and solid phases play a critical role in determining thermal stability and efficiency. The present analysis employs linear stability theory using the normal mode technique, and the resulting eigenvalue problem is solved via the Galerkin-weighted residual method. A comparative study is conducted for three thermal boundary conditions: rigid-rigid <span><math><mrow><mo>(</mo><mi>R</mi><mo>/</mo><mi>R</mi><mo>)</mo></mrow></math></span>, rigid-free <span><math><mrow><mo>(</mo><mi>R</mi><mo>/</mo><mi>F</mi><mo>)</mo></mrow></math></span>, and free-free <span><math><mrow><mo>(</mo><mi>F</mi><mo>/</mo><mi>F</mi><mo>)</mo></mrow></math></span> for the stationary case, while oscillatory instabilities are analyzed for the F/F case. Graphical representations are used to illustrate how the main controlling parameters affect the stationary and oscillatory onset. It is reported that the system is more stable with increasing values of <span><math><mi>H</mi></math></span> (inter-phase heat transfer coefficient) and <span><math><mtext>Da</mtext></math></span> (Darcy number), while it is less stable with increasing values of <span><math><mi>χ</mi></math></span> (Damköhler number), <span><math><msub><mrow><mi>M</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> (linear viscosity variation parameters), <span><math><msub><mrow><mi>M</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> (nonlinear viscosity variation parameters), and <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mi>f</mi></mrow></msub></math></span> (the fluid heat generation parameter). It is also established that the system is more stable for <span><math><mrow><mi>R</mi><mo>/</mo><mi>R</mi></mrow></math></span> boundary combinations and least stable for <span><math><mrow><mi>F</mi><mo>/</mo><mi>F</mi></mrow></math></span> boundaries.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101412"},"PeriodicalIF":0.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145098015","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 and numerical investigation of developing correlations for convective heat transfer coefficient for internal room surfaces considering ceiling diffusers effects","authors":"Sajad Abasnezhad,&nbsp;Abdolsalam Ebrahimpour,&nbsp;Jafar Ghafouri","doi":"10.1016/j.ijft.2025.101421","DOIUrl":"10.1016/j.ijft.2025.101421","url":null,"abstract":"<div><div>An experimental and numerical study analyzed convective heat transfer in a room. The experiments involved measuring temperatures in a room with a window and a diffuser placed in different positions. Numerical simulations modeled a room with windows of varying sizes on the south wall, slot diffusers, and radiators. This research aims to address gaps in calculating convective heat transfer coefficients for innovative window designs by proposing new correlations to improve the accuracy of cooling and heating load predictions. Solar radiation data from Tabriz City was incorporated. Key parameters included volumetric inlet flow rate, diffuser inlet angle, and window-to-wall ratio. CFD simulations employed the SIMPLE algorithm with second-order discretization and the standard K-epsilon turbulence model. The findings indicate that the reference temperature strongly influences the results. Supply temperature consistently showed a higher convective heat transfer coefficient compared to the reference temperature, usually defined as the average room temperature. Moreover, the window-to-wall ratio emerged as the most critical factor, with larger windows leading to a notable increase in the convective heat transfer coefficient.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101421"},"PeriodicalIF":0.0,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119554","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":"Nano enhanced phase change materials for thermal energy storage system applications: A comprehensive review of recent advancements and future challenges","authors":"Bayew Adera ,&nbsp;Venkata Ramayya Ancha ,&nbsp;Tassew Tadiwose ,&nbsp;Eshetu Getahun","doi":"10.1016/j.ijft.2025.101418","DOIUrl":"10.1016/j.ijft.2025.101418","url":null,"abstract":"<div><div>Phase change materials (PCMs) are gaining significant attention for their efficiency in thermal energy storage. Recent research shows that PCMs can enhance heat storage systems' effectiveness when used in photovoltaic (PV) panels. By adding nanoparticles, thermal conductivity and heat transmission are improved. This study aimed to review the recent advancements and future challenges of PCMs based on metallic, carbonic, ceramic, and hybrid nanomaterials. The up-to-date references were taken from the Google search engine. Results indicated that metallic nanoparticles like copper (20 nm) can increase thermal conductivity by up to 46.3 % and diffusivity by 44.9 % with minor changes in phase transition temperatures. While carbonic materials like expanded graphite (EG) show latent heat retention trade-offs, they are 40 times more conductive than pure paraffin. Ceramic nanoparticles, such as Al₂O₃ and Fe₃O₄, enhance structural stability and reduce super-cooling, with Fe₃O₄ composites showing a 60 % conductivity increase. Hybrid systems validated by predictive machine learning techniques integrate conductivity, nucleation, and thermal stability, using materials like graphene-WO₃ nano-fluids and SiO₂-CeO₂-paraffin. These developments highlight nanomaterials' potential to improve paraffin's low conductivity while balancing nanoparticle integration to maintain energy density. Challenges remain in addressing trade-offs like restricted natural convection and decreased latent heat (up to 35 % at high filler loadings). Structural modifications, such as radial fins combined with Al₂O₃ nanoparticles, result in a 28.3 % faster melting rate, compensating for convection losses. Real-world applications demonstrate scalability, with Cu-paraffin composites achieving a 1.7 % efficiency gain and Gr-Ag hybrids extending operation by three hours. Environmentally friendly methods, such as plant-derived iron oxide nanoparticles, prioritize sustainability without compromising functionality. Future research should focus on scalable synthesis, optimal filler interactions, and durability testing to meet global demands for effective, sustainable thermal energy storage solutions.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101418"},"PeriodicalIF":0.0,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159705","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":"Python implementation of the hybrid analytical and numerical method for analytical conversion of numerical thermofluidic boundary layer solutions","authors":"Ali Ahmadi Azar","doi":"10.1016/j.ijft.2025.101419","DOIUrl":"10.1016/j.ijft.2025.101419","url":null,"abstract":"<div><div>The primary objective of this study is to introduce a novel framework for numerically solving the governing equations of boundary layer theory. In this approach, the equations are first solved using an arbitrary numerical method, and the resulting data are subsequently transformed into polynomial-based analytical expressions. This hybrid analytical and numerical method (HAN method) offers a significant advancement by eliminating the reliance on traditional analytical or semi-analytical techniques, which often involve substantial complexity and limitations. The HAN method enables researchers to leverage numerical solvers while simultaneously obtaining analytical representations of the solution. This study employs the HAN method to solve novel governing equations for Blasius-type flow with heat transfer, mass transfer, and entropy generation because current governing equations are re-scaled equations, derived for uniform free-stream flow, are distinct from previous stretching-sheet models. Although the re-scaled governing equations represent a significant mathematical innovation, the HAN methodology stands out as the most prominent contribution of this study. The HAN method first obtains high-accuracy numerical solutions, then converts them into compact analytical expressions, enabling rapid parametric analysis of key dimensionless groups—Prandtl, Schmidt, Eckert, and Brinkman numbers. This work provides four key innovations: a dual literature review, the derivation of novel governing equations, a step-by-step HAN solution guide with Python code, and presentation of novel results. The findings show that increasing the Prandtl number thins the thermal boundary layer and increases the Nusselt number, while the Schmidt number thins the concentration boundary layer and increases the Sherwood number. Entropy generation rises significantly with higher Brinkman numbers and diffusive parameters, and the Bejan number increases with the temperature ratio, indicating a shift toward thermal irreversibility. The velocity field remains unaffected by these parameters. Analytical solutions from HAN show excellent agreement with finite-difference numerical results, validating the method's accuracy.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101419"},"PeriodicalIF":0.0,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159707","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 impact of non-linear heat source on mixed convective chemically reacted MHD hybrid nanofluid/nanofluid/fluid over a stretched region","authors":"Thanatporn Grace ,&nbsp;Ch. Maheswari ,&nbsp;Mohana Ramana Ravuri ,&nbsp;Talha Anwar ,&nbsp;B. Naga Lakshmi ,&nbsp;Shaik Mohammed Ibrahim","doi":"10.1016/j.ijft.2025.101417","DOIUrl":"10.1016/j.ijft.2025.101417","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This study compares &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;F&lt;/mi&gt;&lt;msub&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/msub&gt;&lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;msub&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; hybrid nanofluid, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;msub&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; nanofluid and water, analysing velocity, temperature and concentration profiles. Key parameters include mixed convection, buoyancy ratio forces, space-and-temperature-dependent heat sources, thermophoresis, Brownian motion, Hall current, temperature ratio, magnetic field, rotation parameter, thermal radiation, Schmidt number and chemical reaction. Buongiorno model is applied to explore the model. Similarity transformations reduce the governing partial differential equations (PDEs) to ordinary differential equations (ODEs), solved through MATLAB’s BVP-5C with a shooting method. The analysis reveals that increases in mixed convection and buoyancy enhance the &lt;span&gt;&lt;math&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-direction velocity, whereas magnetic and rotational effects lead to its reduction. The velocity along the &lt;span&gt;&lt;math&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-axis rises with an increase in the magnetic parameter but declines as the Hall current strengthens. Temperature profile increases with higher values of the space- and temperature-dependent heat source, thermophoresis, Brownian diffusion, rotation parameter, Hall current, thermal radiation and temperature ratio. Concentration is enhanced by thermophoresis but reduced by Brownian diffusion, Schmidt number and chemical reaction effects. The heat transfer rate is enhanced by higher space and temperature dependent heat sources, Brownian motion, thermophoresis and chemical reactions, while it is reduced by increased mixed convection and buoyancy ratios. In contrast, the mass transfer rate increases with all the considered parameters. In the case of velocity distribution, the hybrid nanofluid demonstrates a sharper profile along the &lt;span&gt;&lt;math&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-direction under mixed convection, whereas the base fluid displays a stronger variation in this direction when influenced by buoyancy, Hall current and rotational effects. Along the &lt;span&gt;&lt;math&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-direction, the velocity profile of the hybrid nanofluid becomes more pronounced with rising magnetic parameter and Hall current. For the temperature distribution, the hybrid nanofluid attains a considerably higher profile than both nanofluid and base fluid when subjected to space- and temperature-dependent heat generation, thermophoretic forces, Brownian diffusion, Hall current, thermal radiation and temperature ratio. Conversely, the base fluid maintains a steeper concentration gradient in response to thermophoresis, Brownian motion, Schmidt number and chemical reaction parameters. ","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101417"},"PeriodicalIF":0.0,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119439","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":"Loss prevention of cooling tower with an open loop system at cooling tower pipeline on a biodiesel plant: Analysis and safety implications","authors":"Anggara Dwita Burmana ,&nbsp;Mohammad Yazdi ,&nbsp;Rosdanelli Hasibuan ,&nbsp;Iriany ,&nbsp;Taslim","doi":"10.1016/j.ijft.2025.101416","DOIUrl":"10.1016/j.ijft.2025.101416","url":null,"abstract":"<div><div>This study aims to discuss cooling tower corrosion using the gravimetric method, as well as analyse the economic and safety implications of damaged cooling tower pipes in biodiesel plants due to a lack of maintenance. SEM analysis revealed that splashing water from the cooling tower accelerates the formation of a silica crust on the cooling tower suction pump. The System Hazard Identification, Prediction and Prevention (SHIPP) methodology as well as the accident model and Failure Mode and Effect Analysis (FMEA) are presented for future work. In this study data was collected at 10 different points to confirm the thickness of the cooling tower pipe. The corrosion that occurred in the first year was 0.7682 mm/y, while the corrosion that occurred in years 8 to 10 was relatively more stable at around 0.0090 mm/y. The weight loss and metal loss that occurred in the first year were 53 g/y and 0.7251 mm/y, while the weight loss and metal loss that occurred in years 8 to 10 were relatively more stable at around 6.5 g/y and 0.0802 mm/y. Failure to prevent corrosion problems in cooling tower pipes can result in a variety of safety problems, including equipment damage, operational disruptions, environmental impacts, safety hazards and financial consequences</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101416"},"PeriodicalIF":0.0,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097956","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 heat transfer in wavy channels with vortex generators: A CFD investigation","authors":"Aimen Tanougast,&nbsp;Krisztián Hriczó","doi":"10.1016/j.ijft.2025.101405","DOIUrl":"10.1016/j.ijft.2025.101405","url":null,"abstract":"<div><div>The corrugated channel is a widely used method for enhancing heat transfer and has been employed in many thermal engineering applications, such as heat exchangers and compact cooling systems. The corrugated sections create recirculation zones, which can impact flow efficiency. For that reason, we introduced vortex generators. In this study, numerical investigations were conducted on convective heat transfer in a wavy corrugated channel within a Reynolds number (<span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>) range of 500–5000. The wavy channel was equipped with two types of vortex generators (VGs) in this configuration, presenting a novel setup not previously addressed in existing studies: full-circle vortex generators (FCVGs) with different diameters (D = 2, 4, and 6 mm), and two-half-circle vortex generators (THCVGs) with variable distances between the halves (S = 1, 2, and 3 mm). The numerical simulations were performed using the finite volume method in ANSYS Fluent, with the SST <span><math><mi>k</mi></math></span>–<span><math><mi>ω</mi></math></span> turbulence model employed for high Reynolds number flows. The VGs generally improve heat transfer. Performance is measured using the pressure drop ratio (<span><math><mrow><mi>P</mi><mi>R</mi></mrow></math></span>) and the percentage enhancement (<span><math><mrow><mi>P</mi><mi>E</mi></mrow></math></span>). To evaluate thermo-hydraulic performance, the Performance Factor (PF) was also calculated, showing that the FCVG configuration (D = 6 mm) achieved the best balance in laminar flow with a maximum PF of 0.94 at <span><math><mrow><mi>R</mi><mi>e</mi><mo>=</mo><mn>500</mn></mrow></math></span>, while smaller FCVGs performed better in the turbulent regime compared to THCVGs. FCVGs (D = 6 mm) had the largest <span><math><mrow><mi>P</mi><mi>E</mi></mrow></math></span>, increasing by 46% at <span><math><mrow><mi>R</mi><mi>e</mi><mo>=</mo><mn>1000</mn></mrow></math></span>, whereas THCVGs (S = 1 mm) increased by 38% at <span><math><mrow><mi>R</mi><mi>e</mi><mo>=</mo><mn>500</mn></mrow></math></span>. However, because <span><math><mrow><mi>P</mi><mi>R</mi></mrow></math></span> values can rise more for FCVGs than for THCVGs, this enhancement comes at a pressure drop cost. Such improvements enable more compact and efficient heat exchanger designs, supporting energy savings and system miniaturization.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101405"},"PeriodicalIF":0.0,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047862","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":"Thermo-hydraulic performance assessment of mono and hybrid ceramic nanofluids in flat plate solar collectors: a CFD-based study","authors":"Abdel Salam Alsabagh ,&nbsp;Ismail Masalha ,&nbsp;Omer A. Alawi ,&nbsp;Zaher Mundher Yaseen ,&nbsp;Ali Alahmer","doi":"10.1016/j.ijft.2025.101415","DOIUrl":"10.1016/j.ijft.2025.101415","url":null,"abstract":"<div><div>Ceramic nanoparticles have shown great potential in enhancing renewable energy systems and thermal management systems. This study investigates the thermo-hydraulic performance of mono and hybrid nanofluids synthesized by dispersing Titanium diboride (TiB₂), Boron carbide (B₄C), and a hybrid TiB₂: B₄C blend (20:80 weight ratio) into propylene glycol-water (PG: W, 20:80 wt.%) base fluid, with a fixed nanoparticle concentration of 2 wt.%. The thermophysical properties of the nanofluids were evaluated at three inlet temperatures: 298.15 K, 308.15 K, and 318.15 K. A three-dimensional numerical model was developed using ANSYS 2021R1 to simulate flow behavior over a Reynolds number range of 100–900. Key performance indicators included outlet and surface temperatures, heat transfer coefficient (h_tc), Nusselt number (Nu), pressure drop (ΔP), absorbed heat (Q_abs), and energy efficiency (η_eng). At 298.15 K, the TiB₂: B₄C hybrid nanofluid demonstrated a 4.38 % improvement in thermal conductivity over the base fluid (PG:W) and a 26.3 % reduction in viscosity compared to B₄C, demonstrating a balanced enhancement of thermal and flow properties. While B₄C exhibited the highest heat transfer coefficients (12–19 % above PG:W and 4.8–10.4 % higher than TiB₂:B₄C), its high viscosity resulted in increased pumping demands. In contrast, the hybrid nanofluid achieved energy efficiency up to 10 % higher than PG:W while remaining within 2–5 % of B₄C’s performance. With increasing temperature, all nanofluids exhibited a ∼78 % reduction in pumping power due to decreased viscosity, with TiB₂:B₄C consistently requiring the lowest pumping energy, up to 60 % less than B₄C. These results highlight the TiB₂:B₄C hybrid nanofluid as a thermally efficient and energy-saving alternative for practical heat transfer systems.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"30 ","pages":"Article 101415"},"PeriodicalIF":0.0,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097957","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}