International Journal of Thermofluids最新文献

{"title":"Effects of hydrogen enrichment in Methane/Air combustion with different inlet arrangements: A numerical approach","authors":"Arithra Debnath Prithu ,&nbsp;Kazi Mostafijur Rahman ,&nbsp;Md.Rhyhanul Islam ,&nbsp;Didarul Hasan Saharaj ,&nbsp;Md Sabbir Hossain","doi":"10.1016/j.ijft.2025.101112","DOIUrl":"10.1016/j.ijft.2025.101112","url":null,"abstract":"<div><div>Recently, H₂ enrichment for combustion and emission control in internal combustion engines, gas turbines, industrial boilers, and furnaces has been extensively studied. However, H₂ enrichment for various inlet designs to change combustion characteristics has not yet been studied. In this study, the effect of hydrogen enriched air and methane non premixed combustion on dynamic flow behavior, temperature, pollutant emission are investigated in geometries with two distinct inlet arrangements using ANSYS Fluent CFD software. A reduced version of GRI-Mech 3.0 methane chemistry reaction including 19 species was used in the study. Hydrogen was added to methane fuel (CH₄) at the inlet within the range 0∼50 % by mass while the mass flow rate of fuel is constant. The findings indicate that as the H₂ enrichment increases, there is a noticeable shift in the peak temperature towards the fuel inlet. Additionally, the overall temperature of the combustion chamber remains homogenous indicating flame stability and consistent combustion in both geometries. The addition of 50 % H₂ resulted in a reduction of approximately 37 % in the outlet temperature. Besides, H₂ enrichment led to lower CO and CO₂ emissions in both geometries, which is up to 99.99 % reduction in CO and 88.47 % reduction in CO₂ for 50 % H₂ addition. The lower emission of CO and CO₂ could be attributed to the facts that with H₂ enrichment the carbon content in the fuel stream decreases, mixture becomes leaner and subsequently results in more complete combustion. In both inlet configurations, the emission of NO exhibited a slight decrease upon the introduction of 15 % H₂ but beyond 30 % enrichment there was a notable increase in NO production, primarily attributed to the peak temperature zones. In comparison, the second inlet arrangement has produced lower CO and CO₂ emission than the first one, while the first inlet arrangement has resulted in overall lower NO emission.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101112"},"PeriodicalIF":0.0,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143168790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review on thermal efficiency augment of flat plate collector equipped with mono and hybrid nanofluids and with inserts","authors":"L.S. Sundar,&nbsp;Sergio M.O. Tavares,&nbsp;Antonio M.B. Pereira,&nbsp;Antonio C.M. Sousa","doi":"10.1016/j.ijft.2025.101111","DOIUrl":"10.1016/j.ijft.2025.101111","url":null,"abstract":"<div><div>Enhanced utilization of renewable energy resources is essential to meet the growing global energy demand and address the depletion of conventional energy sources. Solar energy, as a renewable and eco-friendly resource, plays a pivotal role in this transition. Solar collectors, including flat plate collectors (FPCs), parabolic collectors, and others, are devices designed to convert solar energy into useful thermal energy. This article investigates the influence of nanofluids on the thermal performance of FPCs, with a specific focus on thermal efficiency. Water-based mono nanofluids containing Al₂O₃, CuO, MWCNTs, TiO₂, SiO₂, and ZnO, along with hybrid nanofluids such as SiC-MWCNT/ethylene glycol, MgO-MWCNT/water, CuO-MWCNT/water, and Al₂O₃-TiO₂/water, were analyzed for their ability to enhance the thermal efficiency. The study comprehensively examines the Nusselt number, friction factor, and thermal efficiency of FPCs operating with these nanofluids, both with and without inserts in the absorber tubes. The study also explores the performance under the natural and forced circulation. Additionally, existing correlations for Nusselt number and friction factor for nanofluids with and without inserts in the absorber tube have been reviewed.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101111"},"PeriodicalIF":0.0,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Irreversibility and Sensitivity analysis of MHD squeezing various shaped nanofluid flow between parallel permeable disks","authors":"Abdul Awal,&nbsp;Md. Sarwar Alam","doi":"10.1016/j.ijft.2025.101109","DOIUrl":"10.1016/j.ijft.2025.101109","url":null,"abstract":"<div><div>The efficiency of the thermodynamic system of a real process strongly depends on the effective controlled of entropy generation rate. The key concern of the present study is to elucidate the entropy generation optimization and sensitivity analysis of the two-dimensional hydromagnetic unsteady squeezing nanofluids flow with different shapes of nanoparticles such as spherical, brick, cylindrical, platelet between two parallel circular disks. The stationary bottom disk is assumed as permeable to generate suction/injunction of the fluid through its porous structure and the top disk squeezes away or towards the bottom disk. Three different nanoparticles such as Co, Ni and Al₂O₃ with different shapes and water as base fluid has been considered. The system of partial differential equations governing the flow is converted to a coupled of non-dimension ordinary differential equations. Then these non-dimension equations are solved via power series and the solutions are analyzed using Hermite- Padé approximation scheme. The effects of the physical flow parameters on entropy generation rate and Bejan number are inspected graphically. It is detected that entropy generation rate and Bejan profile exhibit the higher value for Co-water nanofluid related to Ni-water and Al₂O₃-water nanofluids. Regression analysis predicts that the present method is significant. Moreover, sensitivity analysis indicates that the Brinkman number is more influential than the porosity parameter and nanoparticles volume fraction. The optimal solution is also identified based on the highest desirability.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101109"},"PeriodicalIF":0.0,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of rotating magnetic turbulators on the convective heat transfer and pressure drop through a circular tube: Experimental investigation","authors":"Seyyed Morteza Mansouri,&nbsp;Mohamad Ali Bijarchi,&nbsp;L Siamak K Kazemzadeh Hannani","doi":"10.1016/j.ijft.2025.101108","DOIUrl":"10.1016/j.ijft.2025.101108","url":null,"abstract":"<div><div>In this study, forced convective heat transfer inside a tube is investigated by introducing a novel active method that uses an external rotational magnetic field to rotate magnetic spheres in a tube under constant heat flux. To generate the rotating magnetic field, an electric signal generator with adjustable frequencies is used along with a Rodin star coil. The rotation of the magnetic spheres on the inner surface of the tube and simultaneously around themselves disrupts the hydraulic and thermal boundary layers. Hence, the flow regime shifts from laminar to turbulent, leading to an increase in both convective heat transfer and pressure drop inside the tube, which are respectively, favorable and undesirable impacts. The effect of the location and number of the rotating and non-rotating spheres, as well as their presence and absence, and their rotation direction relative to each other on the local and average Nusselt numbers, friction coefficient, and thermal performance factor is studied. Results show that the existence of the rotating magnetic spheres leads to a remarkable elevation in the local Nusselt number after the sphere. Hence, the average Nusselt number is increased significantly in the case of rotating spheres compared to the simple tube. By increasing the number of rotating spheres, locating the rotating spheres closer to the upstream, or rotating the spheres opposite to each other, the average Nusselt number increases, while the enhancement of friction coefficient is negligible. Hence the thermal performance factor elevates up to 24% compared to a simple tube.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101108"},"PeriodicalIF":0.0,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predictive modeling and optimization of noise emissions in a palm oil methyl ester-fueled diesel engine using response surface methodology and artificial neural network integrated with genetic algorithm","authors":"J.M. Zikri ,&nbsp;M.S.M. Sani ,&nbsp;M.F.F.A. Rashid ,&nbsp;J. Muriban ,&nbsp;G.S. Prayogo","doi":"10.1016/j.ijft.2025.101103","DOIUrl":"10.1016/j.ijft.2025.101103","url":null,"abstract":"<div><div>This research examines the predictive performance of two modeling techniques—Response Surface Methodology (RSM) and an Artificial Neural Network enhanced by a Genetic Algorithm (ANN-GA)—in relation to noise emission levels from a single-cylinder diesel engine running on palm oil methyl ester (POME). By employing different engine speeds and loads within the low to high range, noise emissions were recorded from multiple engine components to evaluate the performance of each predictive model. The outcomes of the experiments were contrasted with the forecasts produced by the RSM and ANN-GA models, emphasizing the goal of reducing error percentages. The analysis indicates that the ANN-GA model consistently yields predictions that align more closely with the experimental noise values compared to the RSM model. The average error for the ANN-GA model was 1.03%, significantly less than the 1.82% average error found with the RSM model. This demonstrates a significant enhancement in predictive accuracy using ANN-GA, highlighting its potential as a dependable tool for forecasting noise emissions in biodiesel-powered engines. Specific components, such as the radiator, crankshaft, and crankcase, exhibited minimal prediction errors under ANN-GA, suggesting that this model is particularly adept at capturing the complex noise emission patterns associated with POME-fueled engines. In summary, the results illustrate that the ANN-GA model outperforms the RSM model in predicting noise emissions under the conditions tested, providing a more accurate and effective method. These findings endorse the feasibility of applying ANN-GA in scenarios where precise noise prediction is crucial, particularly in relation to alternative fuels like POME.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101103"},"PeriodicalIF":0.0,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal and mass diffusion in chemically reactive, radiative hybrid nanofluid (Cu and TiO2) flow over a rotating disk","authors":"Raja Ram Meena,&nbsp;Pooja Sharma","doi":"10.1016/j.ijft.2025.101104","DOIUrl":"10.1016/j.ijft.2025.101104","url":null,"abstract":"<div><div>The current research work is focused on thermal and mass transfer analysis on a hybrid nanofluid (water as a base fluid,) flow over a rotating disk with free convective, viscous dissipation, MHD, and radiation effects. The model was prepared in terms of the nonlinear PDEs and transformed into ODEs by using similarity analysis. Subsequently, it's solved numerically and graphically by ‘using the ‘bvp4c’ tool in MATLAB. The results depict that the fluid radial velocity can be enhanced by reducing the volume fraction of TiO₂, and the azimuthal velocity of the disc is improved, due to nanoparticle TiO₂ vol fraction and buoyancy force. Mass diffusion becomes low in the case of highly chemically reactive conditions. The flow characteristics are significantly influenced by variations in heat generation, thermal radiation, and MHD parameters. The calculated values of shear stress, Nusselt, and Sherwood numbers at the surface of the disk are also incorporated for complete verification. The deliberated model and graphical results have significant contributions in many fields like rotating machinery, lubricants, computer storage devices, viscometry, crystal growth process, etc.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101104"},"PeriodicalIF":0.0,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Parametric study and optimization of thermal performance and pressure drop in heat sinks with double-layer porous microchannels","authors":"Fahimeh Aliyari,&nbsp;Keivan Fallah,&nbsp;Hossein Zolfaghary Azizi,&nbsp;Farhad Hosseinnejad","doi":"10.1016/j.ijft.2025.101085","DOIUrl":"10.1016/j.ijft.2025.101085","url":null,"abstract":"<div><div>In this study, the effective parameters in thermal performance and pressure drop of heat sinks with double-layer porous microchannels were investigated. Initially, a heat sink with porous fins was simulated in ANSYS Fluent 18, and the results were validated against reference data. Subsequently, 340 additional models were simulated with variations in parameters such as microchannel length and width, heat sink wall width and height, inter-channel distance, fluid velocity, and porosity levels (0, 20, 40, 60, and 80 percent). The results indicated that increasing porosity improved thermal performance in all samples, though it also led to higher pressure drops at higher porosity levels. Additionally, parallel flow demonstrated better thermal performance than counter flow across all samples. Reducing the microchannel length and width by 3 times and 4.3 times, respectively, and reducing the microchannel height by up to 4.5 times enhanced thermal performance; however, these changes significantly increased the pressure drop. The effect of flow velocity showed that decreasing the velocity led to a 12-times improvement in thermal performance, yet pressure drop increased by up to 70 times. These findings underscore the importance of optimizing geometric and operational parameters to achieve a balance between high thermal efficiency and acceptable pressure drop in the design of porous heat sinks. In the continuation of the research, the extracted parameters were used as inputs for optimization with a multi-objective genetic algorithm aimed at enhancing thermal performance and reducing pressure drop. Accordingly, the optimization process was pursued using the multi-objective genetic algorithm to find the optimal parameters that achieve the best thermal performance along with the lowest pressure drop, ensuring a desirable balance between improved thermal performance and reduced pressure drop. The convergence results obtained for two parameters in the optimization process demonstrated the success of the optimization method used and confirmed that the optimized parameters can effectively contribute to the enhancement of cooling system performance in industrial applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101085"},"PeriodicalIF":0.0,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational and experimental representation of simplified gas turbine bearing chamber geometries","authors":"Ahmad H. Attia,&nbsp;Budi Chandra,&nbsp;C.A. Toomer","doi":"10.1016/j.ijft.2025.101097","DOIUrl":"10.1016/j.ijft.2025.101097","url":null,"abstract":"<div><div>Gas turbine engines depend on bearing chambers to support and lubricate moving parts, facilitating movement and heat dissipation. However, achieving a uniform oil coating on bearings remains a challenge, often leading to excessive oil consumption and in-flight oil loss. This research aims to establish accurate experimental and CFD methods to measure the residence time distribution (RTD) in a simplified linear geometry, progressing towards investigations in a cylindrical bearing chamber rig.</div><div>The first test case uses an inclined rectangular acrylic channel (140 cm length, 3 cm height, 5 cm width) with a 39° slope and flow rates ranging from 0.9 l/min to 2.7 l/min. This simplified geometry allows the study of fundamental oil film dynamics. The experimental setup is complemented by CFD modelling using the Volume of Fluid (VOF) approach with Large Eddy Simulations (LES) to model turbulence.</div><div>Validation demonstrates high level of accuracy, with film thickness measurements showing an error margin of 0.22 % at lower flow rates and up to 1.7 % at higher velocities. These results confirm the experimental setup and CFD model's reliability, offering a solid foundation for studying multiphase flows in bearing chambers. Future phases will incorporate oil for further validation and refinement.</div><div>The research question we are asking is: <strong><em>Can the proposed method accurately measure the residence time in an experimental setup?</em></strong></div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101097"},"PeriodicalIF":0.0,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143169681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Implementation of the methodology for calculation of the three-phase equilibrium of hydrocarbons and the aqueous phase","authors":"Oleg Aksenov ,&nbsp;Mikhail Kozlov ,&nbsp;Eduard Usov ,&nbsp;Dmitry Taylakov ,&nbsp;Nikita Kayurov ,&nbsp;Alexander Cheremisin","doi":"10.1016/j.ijft.2025.101093","DOIUrl":"10.1016/j.ijft.2025.101093","url":null,"abstract":"<div><div>The paper discusses the development and implementation of the algorithm for calculation of the three-phase equilibrium in the hydrocarbon/aqueous system. The work is done as a part of PVT module improvement for the “d-Flow” hydraulic simulator which is under development at Novosibirsk R&amp;D Center LLC. The numerical methods used in the presented three-phase algorithm are simple and available in the literature, however these methods are often need to be improved and tuned before an actual application. In order to increase phase composition calculation stability, a modification for stationary point selection algorithm is proposed. Moreover, unexpected behavior of the algorithm may be revealed during implementation, which is not described in the original articles. This work attempts to present the three-phase equilibrium calculation algorithm ready for direct use in the designed hydraulic simulator and provide the detailed description for different aspects and difficulties of the implementation. The numerical schemes for the phase stability test and the calculation of equilibrium compositions are described, and the general equilibrium search algorithm is given. To test the algorithm, simulations of different mixtures are done and phase diagrams are presented for several mixtures. The solubility of hydrocarbons in water for binary mixtures is also calculated and compared with experimental data from the literature.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101093"},"PeriodicalIF":0.0,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143168151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance evaluation of interrupted and hybrid channel heat sinks for a triple junction high concentrator photovoltaic cell","authors":"Muhammad Usman Sajid,&nbsp;Omer Abedrabboh,&nbsp;Yusuf Bicer","doi":"10.1016/j.ijft.2025.101102","DOIUrl":"10.1016/j.ijft.2025.101102","url":null,"abstract":"<div><div>High concentrator photovoltaic (HCPV) systems are designed to minimize the use of semiconductor materials by concentrating sunlight onto a smaller cell area. However, managing the excess heat generated during this concentration is a significant challenge, as it can affect the efficiency and lifespan of the HCPV cells. Effective thermal management solutions are essential to ensure reliable and cost-effective operation. The objective of this study is to propose interrupted and hybrid channel heat sinks designed to effectively maintain the temperature of HCPV systems within safe operating limits. The present work explores the impact of heat sink channel configuration, concentration ratio, and Reynolds number on the performance of a high concentration triple-junction solar cell. A comprehensive thermal model was developed in COMSOL Multiphysics, and numerical results were validated against multiple sets of available experimental and computational data, ensuring both accuracy and reliability. The results reveal that the hybrid channel design (Geometry F) significantly reduces the maximum solar cell temperature from 82 °C to 78 °C at CR = 1500 and <em>Re</em> = 400, achieving up to a 39.5 % increase in the Nusselt number compared to the conventional straight channel design (Geometry A). Additionally, Geometry (F) maintains a high performance evaluation criterion (PEC) value of 1.22 at <em>Re</em> = 200, reflecting effective thermal-hydraulic performance. Furthermore, Geometry (F) reduces the heat sink weight by 3.7 %, which is particularly advantageous for sun-tracking applications, where minimizing weight is essential.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"26 ","pages":"Article 101102"},"PeriodicalIF":0.0,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}