International Journal of Thermofluids最新文献

{"title":"Thermal and fluid behavior of nanofluids over a rotating disk: Influence of Darcy–Forchheimer and slip conditions","authors":"Mahmmoud M. Syam","doi":"10.1016/j.ijft.2025.101316","DOIUrl":"10.1016/j.ijft.2025.101316","url":null,"abstract":"<div><div>Understanding nanofluid flow over rotating disks embedded in porous media is crucial for advancing applications in thermal energy systems, microfluidics, and industrial cooling. This comprehensive study investigates nanofluids’ thermal and mass transport characteristics influenced by slip flow, magnetic effects, and the Darcy–Forchheimer porous medium model. The governing equations are transformed using similarity variables and solved using a modified operational matrix method with exceptional accuracy (truncation error <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup></mrow></math></span>). Numerical simulations reveal that increasing the Hartmann number <span><math><mrow><mi>H</mi><mi>a</mi></mrow></math></span> from 0.0 to 1.0 leads to a 52% decrease in radial velocity <span><math><mrow><msup><mrow><mi>f</mi></mrow><mrow><mo>′</mo></mrow></msup><mrow><mo>(</mo><mi>η</mi><mo>)</mo></mrow></mrow></math></span> and a 28% increase in temperature profile <span><math><mrow><mi>θ</mi><mrow><mo>(</mo><mi>η</mi><mo>)</mo></mrow></mrow></math></span> due to the damping effect of Lorentz forces. Similarly, increasing the velocity slip parameter <span><math><mi>α</mi></math></span> from 0.15 to 0.9 results in a 38% drop in radial velocity and a 27% rise in fluid temperature. The Brownian motion parameter <span><math><mrow><mi>N</mi><mi>b</mi></mrow></math></span> and thermophoresis parameter <span><math><mrow><mi>N</mi><mi>t</mi></mrow></math></span> significantly impact concentration profiles, with <span><math><mrow><mi>N</mi><mi>t</mi></mrow></math></span> increasing <span><math><mrow><mi>θ</mi><mrow><mo>(</mo><mi>η</mi><mo>)</mo></mrow></mrow></math></span> by 30% and reducing <span><math><mi>ϕ</mi></math></span> by 21%. Skin friction coefficients computed using our method match closely with benchmark solutions from Mathematica and literature, confirming model validity. These findings underscore the practical implications of our study. They demonstrate the strong coupling between magnetic, porous, and slip effects in either enhancing or suppressing transport phenomena. This insight offers a valuable guide for optimizing nanofluid-based systems in practical engineering applications, potentially leading to significant advancements in thermal energy systems, microfluidics, and industrial cooling.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"28 ","pages":"Article 101316"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556728","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":"Effects of carbon nanotube concentration on heat transfer characteristics in turbulent mixtures","authors":"Javad Zareei ,&nbsp;John William Grimaldo Guerrero ,&nbsp;Shoira Formanova ,&nbsp;KDV Prasad ,&nbsp;Sabir Tagelsir Hassan Widatalla","doi":"10.1016/j.ijft.2025.101326","DOIUrl":"10.1016/j.ijft.2025.101326","url":null,"abstract":"<div><div>This study presents numerical simulations modeling convective heat transfer in turbulent flows of carbon nanotube (CNT) mixtures suspended in water. The RNG k-ε turbulence model is employed and simulations are performed using the FLUENT software. The effects of varying nanoparticle concentration on the heat transfer characteristics are investigated. The results indicate that the presence of nanoparticles significantly increases the convective heat transfer coefficient, while their effect on pressure drop is minimal. The introduction of an excitation near the wall and the stimulation of the boundary layer further affect heat transfer, initially decreasing the heat transfer coefficient in the immediate vicinity, but significantly increasing it shortly thereafter. Incorporating CNTs into the base fluid at low volume fractions effectively improves heat transfer. In addition, positioning a barrier adjacent to the boundary layer results in a transient decrease in the heat transfer coefficient, followed by a significant increase. In particular, increasing the concentration of nanofluids from 0.1 % to 0.8 % leads to a remarkable increase in the heat transfer coefficient. However, further increasing the CNT concentration from 0.8 % to 1 % results in only a marginal increase in the heat transfer coefficient, accompanied by a significant increase in the frictional pressure drop.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"28 ","pages":"Article 101326"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144589354","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":"Exploration of Casson hybrid nanofluid (Cu−Al2O3/EG) flow over an exponentially heated stretchy sheet with radiation absorption and viscous dissipation: A modified Buongiorno model","authors":"S. Baskaran ,&nbsp;R. Sowrirajan ,&nbsp;S. Eswaramoorthi ,&nbsp;K. Loganathan ,&nbsp;Balachandra Pattanaik","doi":"10.1016/j.ijft.2025.101301","DOIUrl":"10.1016/j.ijft.2025.101301","url":null,"abstract":"<div><div>The past few decades have seen a notable rise in research on non-Newtonian fluid models. The Casson fluid serves as a prominent representation of non-Newtonian fluids. The widespread interest can be linked to the valuable applications of these models across different engineering fields and industries. This analysis focused on the flow of a Casson fluid mixed with (Cu) and (<span><math><mrow><msub><mrow><mtext>Al</mtext></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mtext>O</mtext></mrow><mrow><mn>3</mn></mrow></msub></mrow></math></span>) nanoparticles in ethylene glycol across a heated porous exponentially stretchy sheet with slip, radiation, viscous dissipation and radiation absorption effects. Employing suitable transformations, the system of governing nonlinear partial differential equations are reformed into ordinary differential equations, which are numerically computed by adopting the bvp4c solver in MATLAB. Tables and figures are used to explore the effects of essential factors on velocity, temperature, and nanofluid concentration distributions and also the skin friction coefficient, the local Nusselt number, and the local Sherwood number. The velocity of the fluid diminutives with an enhanced values of the Casson parameter. The temperature distribution elevates as the Brownian motion and thermophoresis parameters enrich. An escalation in the Lewis number and the Brownian motion parameter promotes a reduction in the nanofluid concentration profile. The mass transference rate is enhanced by the amplification of Brownian motion and thermophoresis parameters.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"28 ","pages":"Article 101301"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A dual-purpose solar collector as a parallel flow heat exchanger: A novel mathematical framework","authors":"Mustafa Moayad Hasan ,&nbsp;Krisztián Hriczó","doi":"10.1016/j.ijft.2025.101322","DOIUrl":"10.1016/j.ijft.2025.101322","url":null,"abstract":"<div><div>The solar thermal system is a crucial segment of solar energy technologies. Maximizing the efficiency of the collector contributes significantly to boosting the entire performance of solar thermal systems. Among them, a dual-purpose solar collector, which fulfills the bi-function of producing hot water and air concurrently, is particularly important. Maximizing the efficiency of such a collector remains a significant challenge that affects overall energy utilization. In this research, the dual-purpose solar collector was treated as a parallel flow heat exchanger, and a unique mathematical analysis was developed using the effectiveness-number of transfer unit approach. This innovative approach applies a well-established equation from the realm of parallel flow heat exchangers to this new context, which has not been previously explored in the literature. To ensure the reliability and robustness of the suggested model, the obtained results were compared with experimental data from existing studies, focusing on two key metrics: relative percentage error and average relative percentage error. The analysis yielded a relative percentage error of 2.94% and an average relative percentage error of 1.3%. These metrics fall within acceptable limits, indicating a strong correlation between the predictions made by the suggested model and the experimental observations available in the literature. The developed mathematical model demonstrates an accurate prediction of dual-purpose solar collector performance, providing researchers with a reliable tool for evaluating the suitability of these systems for a range of applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"28 ","pages":"Article 101322"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556727","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":"Slip-induced variations in MHD nanofluid (Cu-Al2O3) flow over a permeable stretching sheet with dissipation and thermal radiation: Role of Dufour and Joule heating effects","authors":"Nalivela Nagi Reddy ,&nbsp;B.Shankar Goud ,&nbsp;Hussein Maaitah ,&nbsp;Mohamad Y. Mustafa","doi":"10.1016/j.ijft.2025.101320","DOIUrl":"10.1016/j.ijft.2025.101320","url":null,"abstract":"<div><div>In this article, research has focused on the effects of Joule heating, thermal radiation, and viscous dissipation on the flow of unsteady MHD nanofluids over a porous stretched sheet. The model composed of equations is modified to propose an acceptable dimensionless character. With the aid of similarity transformations, the non-linear PDEs transform into the non-linear ODES. The Kellerbox is a method used in MATLAB software to solve a few pairs of transformed equations and subsequently describe altered boundary conditions. In addition to the outcomes for the distinct nanofluid types, there is a table and graphical representation of the properties of <em>Al</em>₂<em>O</em>₃ and Cu nanofluids. The tabular and graphical findings show the physical relevance of the effort level. The findings are shown to be quite satisfactory in agreement with the work which was already outlined in the scientific literature. Displayed graphically and in tabular form are the results that quantify the physical significance of the effort. The Cu nanofluid exhibited much greater thermal gradients compared to the <em>Al</em>₂ <em>O</em>₃ nanofluid for all parameters <em>S</em>_θ, <em>A</em>,  <em>B</em>,  <em>R</em>,  <em>Du</em>, and Ec. When contrasting the two nanofluids, this came out as the result. The velocity patterns of <em>Al</em>₂ <em>O</em>₃ nanofluid were much greater than those of Cu nanofluid when comparing the two materials concerning the variables <em>M</em>,  <em>K_p</em>, <em>S</em>, and <em>f_w</em>.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101320"},"PeriodicalIF":0.0,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686522","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":"Analysis of heat-not-burn (HNB) smoking system technologies","authors":"José Cataldo","doi":"10.1016/j.ijft.2025.101319","DOIUrl":"10.1016/j.ijft.2025.101319","url":null,"abstract":"<div><div>A conceptual model was proposed to evaluate the time evolution of the air velocity field, as well as the temperature evolution, in a porous medium, such as the tobacco bed placed in a study volume, and the content of the various substances contained in the tobacco product such as water, glycerin and nicotine. It was found that the time step during which the momentum changes is at least two orders of magnitude smaller than the time step for temperature and mass changes, leading to the decision to decouple the resolution of the balances. The study volume is a cylinder with a diameter of 10 mm and a height of 17 mm, containing tobacco strands no longer than 5 mm and with a cross-section of 1.3 mm by 0.2 mm, to which heat is applied through the outer surface. Operating conditions were analyzed based on the compactness of the tobacco mass in the study volume (300 mg, 400 mg and 600 mg), the nominal temperature of the outer surface of the study volume (150 °C, 200 °C and 220 °C) and the time required to reach this temperature during the heating period (40 s or 50 s). The pressure difference applied to the porous bed was estimated using a model that was experimentally verified, with a flow rate of 17.5 ml/s applied during each puff in all cases. It was experimentally verified that the developed model satisfactorily reproduced the time evolution of the temperature during the heating process. In cases of high compactness, greater uniformity of the temperature field and higher temperatures in the tobacco mass were observed compared to cases of low compactness. In cases of low compactness, a central zone was identified where substances such as nicotine would not be consumed, while at the wall it would be consumed in a puff. In the case of higher compactness, a more uniform behavior was achieved, with durations ranging from 4 to 37 puffs. It was identified that energy consumption would reach a minimum depending on the load for a given nominal temperature. The consumption of water contained in the tobacco influences how the temperature changes over time. It was observed that the temperature distributions seem to scale with the diameter of the oven and that, as the diameter increases, a larger region appears where the temperature seems uniform and the temperature at the center becomes higher.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"28 ","pages":"Article 101319"},"PeriodicalIF":0.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502389","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":"Magnetohydrodynamics phenomena in continuous casting process under applied electromagnetic braking (EMBr)","authors":"Alexander Vakhrushev ,&nbsp;Ebrahim Karimi-Sibaki ,&nbsp;Menghuai Wu ,&nbsp;Mohamad Al Nasser ,&nbsp;Gernot Hackl ,&nbsp;Yong Tang ,&nbsp;Josef Watzinger ,&nbsp;Jan Boháček ,&nbsp;Abdellah Kharicha","doi":"10.1016/j.ijft.2025.101315","DOIUrl":"10.1016/j.ijft.2025.101315","url":null,"abstract":"<div><div>In the presented work the effects of electromagnetic braking (EMBr) are gathered, exemplifying key magnetohydrodynamics (MHD) phenomena in continuous casting (CC) process. The complex interactions between turbulent liquid metal flows and a direct current (DC) magnetic field through the meso‑to-macro scale cascade are reviewed. We analyze MHD influences on different types of melt motion in CC, including jets, recirculation zones, and shear flows, as well as Lorentz force-induced acceleration in stagnant regions. These phenomena result from the distribution of induced electric current lines closing through either the liquid bulk or the semiconducting solidifying shell. The continuously growing shell, formed against the water-cooled copper mold walls, is significantly affected by the hot melt flow patterns. The study highlights practical applications of EMBr to optimize flow dynamics in the CC process, providing insight into improving casting stability and product quality.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"28 ","pages":"Article 101315"},"PeriodicalIF":0.0,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491768","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":"Binary chemical reaction, Soret and Dufour effects on Williamson nanofluid flow over a stretching cylindrical porous sheet","authors":"Gizachew Bayou Zegeye,&nbsp;Eshetu Haile,&nbsp;Gurju Awgichew,&nbsp;Eyaya Birara","doi":"10.1016/j.ijft.2025.101289","DOIUrl":"10.1016/j.ijft.2025.101289","url":null,"abstract":"<div><div>The intention of the paper is to scrutinize the combined impacts of binary chemical reaction, Soret and Dufour effects on Magnetohydrodynamics (MHD) Williamson nanofluid flow over a steady stretching cylindrical porous sheet. Similarity transformation and linearization technique are used to transform the governing non-linear partial differential equations into a system of first order initial value problems. The Runge–Kutta fourth order with the shooting technique aided with python programming is used to solve the system of initial value problems. The implemented method is validated with formerly published article. Graphs are used to observe the influence of different parameters on velocity, temperature and concentration profiles. Moreover, in response to different parameters, the effects of skin friction, heat and mass flux dynamics are presented. The results of the study revealed that the temperature near the cylinder’s wall is initiated whereas the concentration gets retarded as the respective Soret and Dufour numbers are increased. The coefficient of skin friction rises and hence the velocity is declined for higher values of Forchheimer number. As Soret, Dufour numbers and destructive chemical reaction parameter are increased, the rate of heat flux is retarded.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"28 ","pages":"Article 101289"},"PeriodicalIF":0.0,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338787","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":"Thermodynamic assessment of power generation from waste heat in natural gas compressor station: A case study","authors":"Arif Karabuga ,&nbsp;Murat Iskender ,&nbsp;Behiye Yuksel ,&nbsp;Elif Sultan Aydin ,&nbsp;Zafer Utlu ,&nbsp;Ferhat Eti","doi":"10.1016/j.ijft.2025.101313","DOIUrl":"10.1016/j.ijft.2025.101313","url":null,"abstract":"<div><div>This study presents a comprehensive thermodynamic and economic assessment of an Organic Rankine Cycle (ORC) system for waste heat recovery in natural gas compressor stations. The research systematically evaluates the impact of critical thermodynamic parameters, including turbine inlet temperature, pressure, working fluid flow rate, and exhaust gas temperature, on both energy and exergy efficiencies. The findings, system energy and exergy efficiencies increase by 22.52 % and 22.41 %, respectively. Additionally, an economic analysis was conducted to evaluate the feasibility of the system. The results indicate that higher turbine inlet temperatures contribute to lower LCOE, improving cost-effectiveness, while also enhancing sustainability through increased exergy efficiency. Additionally, a sensitivity analysis was performed using the Theil-Sen Robust Estimator, confirming that the system remains operationally stable across reasonable fluctuations in key parameters. These findings highlight ORC technology as an effective and sustainable solution for waste heat recovery, offering both economic and environmental benefits in industrial applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"28 ","pages":"Article 101313"},"PeriodicalIF":0.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144510814","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 thermal management in microelectronic cooling: A study on pairing multiple pin-fin shapes in microchannel heat sinks","authors":"Kaouthar Madi ,&nbsp;Ahmed Raafat ,&nbsp;Saeed Al Nuaimi","doi":"10.1016/j.ijft.2025.101283","DOIUrl":"10.1016/j.ijft.2025.101283","url":null,"abstract":"<div><div>In the last decade, microelectronics have advanced significantly, resulting in higher generated heat flux, which, if not managed carefully, may lead to damage or even failure. Pin-fin microchannels are one of the promising techniques that can be used to enhance heat dissipation. This study investigates the thermal and hydrodynamic performance of microchannel heat sinks incorporating different pin fin shapes: square (S), circle (C), and triangle (T). Additionally, various combinations of these shapes, including triangle–square (T–S), triangle–circle (T–C), and triangle–circle–square (T–C–S), were explored to study the effect of combining different shapes on performance metrics. Numerical simulations, validated against experimental data, were conducted under laminar flow conditions for Reynolds numbers ranging from 250 to 1500. The results showed that circular pin fins exhibited a pressure drop 8%–90% lower than other configurations, while square pin fins demonstrated the highest temperature drop along the channel, indicating good thermodynamic performance but at the cost of 90.9% higher power consumption. Triangular pins balanced the thermodynamic and hydraulic performance, with a Nusselt number of 12.6 and a pressure drop 14.4% higher than circular pin fins. Some hybrid configurations combined the advantages of single pin shapes: the T–S arrangement achieved the highest Nusselt number (12.9) with 48.4% lower pressure drop than square pins, while the T–C hybrid maintained a pressure drop close to the circular pin case (8% deviation) while providing high overall efficiency (second best among all configurations). The findings demonstrate that while certain pin shapes perform well individually, hybrid configurations can further enhance the overall performance of microchannel heat sinks.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"28 ","pages":"Article 101283"},"PeriodicalIF":0.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491769","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}