International Journal of Thermofluids最新文献

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A novel planar module design for improved direct contact membrane distillation: Experimental and computational fluid dynamics insights 一种新的平面模块设计,用于改进直接接触膜蒸馏:实验和计算流体动力学的见解
International Journal of Thermofluids Pub Date : 2025-08-22 DOI: 10.1016/j.ijft.2025.101391
Mohamed Z. Khatab , Mostafa M. Abdelsamie , Hassan A. Arafat , Mohamed I.Hassan Ali
{"title":"A novel planar module design for improved direct contact membrane distillation: Experimental and computational fluid dynamics insights","authors":"Mohamed Z. Khatab ,&nbsp;Mostafa M. Abdelsamie ,&nbsp;Hassan A. Arafat ,&nbsp;Mohamed I.Hassan Ali","doi":"10.1016/j.ijft.2025.101391","DOIUrl":"10.1016/j.ijft.2025.101391","url":null,"abstract":"<div><div>Despite the simplicity of direct contact membrane distillation (DCMD) systems, their performance has not yet met high expectations. While significant research has been conducted at the lab scale to enhance DCMD efficiency, the effects of entry and exit flow have largely been overlooked. This study introduces a novel DCMD cell design, which was experimentally tested and compared to the traditional design commonly used in membrane research. Both designs were evaluated under identical conditions, including flow velocity, feed and permeate inlet temperatures, membrane cell dimensions, and the effective membrane surface area. The experimental results demonstrated that the proposed topology outperformed the traditional one by 47 % - 84 %, considering the operating conditions. Additionally, when net spacers were used, the performance difference between the two designs decreased to 17 % - 32 % depending on the operating temperature condition, with the new design consistently showing higher productivity. To further explore these differences, the CFD analysis revealed that dead and wake zones in conventional design were key factors contributing to low flux, while the proposed design exhibited improved heat convection, resulting in higher thermal performance and overall system efficiency.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101391"},"PeriodicalIF":0.0,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144902327","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}
引用次数: 0
Experimental investigation of robust and hydrophobic solar cell cover glass with transparent, self-cleaning hybrid SiO2/TiO2 coatings 透明自清洁SiO2/TiO2杂化涂层坚固疏水太阳能电池盖板玻璃的实验研究
International Journal of Thermofluids Pub Date : 2025-08-21 DOI: 10.1016/j.ijft.2025.101390
Pooya Hooshyar , Ali Nafez , Hesam Moghadasi , Seyed Ali Moosavi , Ali Moosavi
{"title":"Experimental investigation of robust and hydrophobic solar cell cover glass with transparent, self-cleaning hybrid SiO2/TiO2 coatings","authors":"Pooya Hooshyar ,&nbsp;Ali Nafez ,&nbsp;Hesam Moghadasi ,&nbsp;Seyed Ali Moosavi ,&nbsp;Ali Moosavi","doi":"10.1016/j.ijft.2025.101390","DOIUrl":"10.1016/j.ijft.2025.101390","url":null,"abstract":"<div><div>Utilizing advanced spray-coating techniques, a cutting-edge coating is developed, boasting transparency, self-cleaning capabilities, durability, and water resistance. By combining modified titanium dioxide (TiO<sub>2</sub>) nanoparticles with a silica (SiO<sub>2</sub>) binder, a potent solution is applied to glass surfaces. This coating effectively repels water, exhibiting contact angles ranging from 121.7° to 143.2°, showcasing its resilience. Under the scrutiny of Scanning Electron Microscopy (SEM), a captivating nanoparticle pattern emerges on the glass, forming a unique micro-nano architecture. Spectroscopic analysis, employing Ultraviolet–visible spectroscopy (UV-Vis) technology, affirms the coating's ability to maintain clarity and enhance translucency. Tested on a Photovoltaic module, the coating's self-cleaning properties are confirmed. Additionally, an image processing approach was employed to assess the coating's performance in dust repulsion. The coating exhibited strong resistance to basic solutions, maintaining a comparable soiled ratio to the unexposed sample even after soaking in sodium hydroxide. Similarly, the coating's performance in repelling dust particles after mechanical abrasion on sandpaper was evaluated. After four cycles, the coating showed improvement in roughness, enhancing its efficacy. However, beyond five cycles of mechanical abrasion, coating degradation occurred, leading to its removal from the surface. This innovative technology holds immense potential for a variety of applications, promising heightened performance and durability in optical environments.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101390"},"PeriodicalIF":0.0,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908561","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}
引用次数: 0
Explore the impacts of thermal radiation on Oxytactic and Gyrotactic microbes in SWCNTs+MWCNTs /water based hybrid nanofluid with Soret-Dufour effects 探讨热辐射对具有Soret-Dufour效应的SWCNTs+MWCNTs /水基混合纳米流体中Oxytactic和Gyrotactic微生物的影响
International Journal of Thermofluids Pub Date : 2025-08-21 DOI: 10.1016/j.ijft.2025.101388
Munawar Abbas , Mostafa Mohamed Okasha , Ali Akgül , Mustafa Bayram , Farrukh Yuldashev , Qasem Al-Mdallal , Hakim AL Garalleh , Zuhair Jastaneyah
{"title":"Explore the impacts of thermal radiation on Oxytactic and Gyrotactic microbes in SWCNTs+MWCNTs /water based hybrid nanofluid with Soret-Dufour effects","authors":"Munawar Abbas ,&nbsp;Mostafa Mohamed Okasha ,&nbsp;Ali Akgül ,&nbsp;Mustafa Bayram ,&nbsp;Farrukh Yuldashev ,&nbsp;Qasem Al-Mdallal ,&nbsp;Hakim AL Garalleh ,&nbsp;Zuhair Jastaneyah","doi":"10.1016/j.ijft.2025.101388","DOIUrl":"10.1016/j.ijft.2025.101388","url":null,"abstract":"<div><div>The current paper investigates the effect of thermal radiation on Darcy-Forchheimer flow of MHD hybrid nanofluid with Soret-Dufour effects and activation energy towards three distinct geometries (wedge, flat plate and cone) including motile Oxytactic and gyrotactic microbes. The proposed model has significant uses in a number of environmental and engineering process. It is essential for improving heat transfer efficiency in cooling systems based on nanofluids, including those used in nuclear reactors, electronic devices, and biomedical applications. Because oxytactic and gyrotactic bacteria are included, it is pertinent to wastewater treatment, as microbial activity promotes the breakdown of pollutants. By improving thermal management in hot conditions, the work also helps aerodynamic and aerospace engineering. By enhancing energy absorption and heat dissipation, thermal radiation's effects on SWCNTs (Single-wall carbon nanotubes) and MWCNTs (Multi-wall carbon nanotubes) nanoliquid further support renewable energy technologies like solar thermal systems. The SWCNTs and MWCNTs are added to water, which acts as the improper liquid, to generate a trihybrid fluid. The MATLAB Bvp4c method is used to solve the equations. The outcomes show that the flow towards the cone has the most significant density gradient of Oxytactic and gyrotactic microbes, as well as the highest rates of mass and heat transmission. The results of the present study will be useful for several microorganisms enhance transportation operations, architectural design systems, oil recovery systems, and medical sectors that use nanofluid.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101388"},"PeriodicalIF":0.0,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144912773","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}
引用次数: 0
Response surface methodology simulations for thermal radiative heat and mass transfer in an inclined rectangular cavity by Oseen-Linearization approach 用oseen -线性化方法模拟倾斜矩形腔内的热辐射传热传质响应面方法
International Journal of Thermofluids Pub Date : 2025-08-20 DOI: 10.1016/j.ijft.2025.101386
D.R. Sasi Rekha , Konduru Sarada , Talha Anwar , Naveen Kumar R , Vikas K
{"title":"Response surface methodology simulations for thermal radiative heat and mass transfer in an inclined rectangular cavity by Oseen-Linearization approach","authors":"D.R. Sasi Rekha ,&nbsp;Konduru Sarada ,&nbsp;Talha Anwar ,&nbsp;Naveen Kumar R ,&nbsp;Vikas K","doi":"10.1016/j.ijft.2025.101386","DOIUrl":"10.1016/j.ijft.2025.101386","url":null,"abstract":"<div><div>An inclined rectangular cavity represented as a two-dimensional rectangular enclosure is inclined relative to a heat source or its surroundings, and thermal radiation occurs within this cavity. The surface’s temperature and emissivity determine the amount of radiation released. Understanding such systems is crucial in applications comprising solar energy collection, heat control in electronics, and furnace designs. With the help of response surface methodology, the heat transmission rate is assessed. Through natural convection, the action of thermal radiation in an inclined enclosure allows mass and heat transfer to be examined analytically, assuming the fluid is Newtonian. This work investigates the analytical procedure that makes use of boundary layer computation and the Oseen linearization approach. There is an Oseen-linear solution for the rectangular tilted cavity containing a mix of arbitrary buoyancy ratios. The findings show that an increase in radiation raises velocity. This suggests a linear vertical stratification in the inner core and a sharp decline in temperature and concentration. As the buoyancy ratio increases, the tilt angle’s impact on Nusselt and Sherwood values shows that concentration and heat effects predominate. As the Rayleigh number and radiation parameter are raised, these figures peak. The steady-state Nusselt and Sherwood values become closer to the conduction value from every direction when the radiation intensity is sufficiently high.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101386"},"PeriodicalIF":0.0,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144902328","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}
引用次数: 0
Characteristics of dissipative forces on thermal and solutal transport in boger fluid with thermophoretic particle deposition: An intelligent neuro-computing paradigm 热反射粒子沉积对热流体和溶质输运的耗散力特征:一种智能神经计算范式
International Journal of Thermofluids Pub Date : 2025-08-20 DOI: 10.1016/j.ijft.2025.101382
Munawar Abbas , Abdulbasit A. Darem , Asma A. Alhashmi , Nashwan Adnan Othman , Dilsora Abduvalieva , Youssef El Khatib , Ali Akgül , Muhammad Shafique
{"title":"Characteristics of dissipative forces on thermal and solutal transport in boger fluid with thermophoretic particle deposition: An intelligent neuro-computing paradigm","authors":"Munawar Abbas ,&nbsp;Abdulbasit A. Darem ,&nbsp;Asma A. Alhashmi ,&nbsp;Nashwan Adnan Othman ,&nbsp;Dilsora Abduvalieva ,&nbsp;Youssef El Khatib ,&nbsp;Ali Akgül ,&nbsp;Muhammad Shafique","doi":"10.1016/j.ijft.2025.101382","DOIUrl":"10.1016/j.ijft.2025.101382","url":null,"abstract":"<div><div>The goal of this examination is to evaluate the Marangoni convection influences on gyrotactic microbes in Boger fluid flow across a sheet with porous medium and thermophoretic particle deposition. The thermophoretic particle deposition is a basic method in electrical and aero-solution engineering for transporting small particles across a temperature gradient. Our model combines the Levenberg–Marquardt method with AI-based neural networks for higher accuracy than traditional methods. It supports industrial fluid dynamics, biomedical engineering, and environmental research. AI-based forecasts also enhance nanofluid heat transfer and advanced biotechnology applications. The proposed paradigm has significant applications in bioengineering, environmental sciences, and industrial operations. Enhancing microbial mobility in bioreactors can enhance the production of biofuel and wastewater treatment. In the medical sciences, targeted medication delivery is aided by an understanding of microbe dynamics in non-Newtonian fluids. The model also advances nanotechnology by improving particle deposition techniques in microfluidic devices. By assessing how microorganisms react to external stimuli, it promotes ecological balance and water quality regulation in marine environments. In a range of engineering and scientific domains, the intelligent neuro-computing approach enhances prediction accuracy even more, making it a practical instrument for real-time monitoring and optimization.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101382"},"PeriodicalIF":0.0,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908477","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}
引用次数: 0
Friction loss for newtonian and power – Law fluids in expanding and contracting duct flows using the lattice boltzmann method 用晶格玻尔兹曼方法计算牛顿和幂律流体在膨胀和收缩管道流动中的摩擦损失
International Journal of Thermofluids Pub Date : 2025-08-19 DOI: 10.1016/j.ijft.2025.101380
José Luis Velázquez Ortega
{"title":"Friction loss for newtonian and power – Law fluids in expanding and contracting duct flows using the lattice boltzmann method","authors":"José Luis Velázquez Ortega","doi":"10.1016/j.ijft.2025.101380","DOIUrl":"10.1016/j.ijft.2025.101380","url":null,"abstract":"<div><div>This study investigates the hydrodynamic behavior of Newtonian and power-law non-Newtonian fluids in a channel with a contraction–expansion–contraction configuration, using the Lattice Boltzmann Method (LBM). Unlike previous research focused on isolated discontinuities, this work introduces a more realistic geometry to capture complex transient phenomena such as vortex formation, flow separation, and shear stress redistribution. Numerical simulations were conducted on a two-dimensional domain and validated against the analytical Poiseuille solution, showing relative errors below 2 %. The analysis was divided into three zones: entrance (A), expansion (B), and contraction (C). In Zone A, the product fRe converged toward the theoretical value of 64, confirming fully developed laminar flow. The head loss coefficient K exhibited a decreasing trend with the generalized Reynolds number, depending on the flow behavior index n. A two-K model was fitted to the data with excellent agreement (relative error below 0.001 %), and the parameters were generalized as functions of n, allowing predictions for fluids beyond those explicitly simulated. In Zone B, the sudden expansion induced complex flow reorganizations, with vortex formation and local recirculation. Although no predictive model was established for this region due to nonlinear and transient effects, the behavior was interpreted using rheological principles. Unlike conventional approaches that artificially fix the Reynolds number, this study applies a constant body force (F) —physically equivalent to a pressure gradient— allowing the generalized Reynolds number (Re<sub>g</sub>) to emerge naturally from fluid rheology (n, k) and flow geometry. This approach demonstrates how rheology modulates flow reorganization under realistic driving conditions, offering a more faithful representation of flow-rheology interactions in CEC configurations. Overall, the results provide a predictive framework for energy loss assessment in systems combining abrupt geometric discontinuities (sudden expansions/contractions) with complex rheological behavior (from pseudoplastic to dilatant fluids), with direct applications in biomedical devices, food processing, and non-Newtonian fluid transport systems.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101380"},"PeriodicalIF":0.0,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144902281","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}
引用次数: 0
Dynamics of kerosene-based nanofluid in the core region of curved pipe surrounded by a peripheral region containing water-based nanofluid 煤油基纳米流体在被水基纳米流体包围的弯曲管核心区域的动力学
International Journal of Thermofluids Pub Date : 2025-08-18 DOI: 10.1016/j.ijft.2025.101383
H. Shahzad, Z. Abbas, M.Y. Rafiq
{"title":"Dynamics of kerosene-based nanofluid in the core region of curved pipe surrounded by a peripheral region containing water-based nanofluid","authors":"H. Shahzad,&nbsp;Z. Abbas,&nbsp;M.Y. Rafiq","doi":"10.1016/j.ijft.2025.101383","DOIUrl":"10.1016/j.ijft.2025.101383","url":null,"abstract":"<div><div>This study investigates the flow dynamics and heat transfer characteristics of two immiscible nanofluids (kerosene-<em>ZnO</em> and water-<em>Cu</em>) flowing through a heated curved pipe under a constant axial pressure gradient, with applications in biomedical devices and industrial heat exchangers where curved geometries and multi-fluid systems are prevalent. The research addresses a critical gap in understanding how curvature-induced secondary flows and nanoparticle properties influence thermal performance in such configurations. By employing a perturbation method and non-dimensional analysis, we derived analytical solutions to the modified Navier-Stokes equations to examine the velocity and temperature distributions. Our analysis systematically varied key parameters, including curvature ratio, Reynolds number, and nanoparticle concentration to quantify their effects. The results demonstrate that increasing the curvature ratio to 0.1 enhances axial velocity near the outer wall by 15–25 % due to centrifugal forces, while higher Reynolds numbers above 50 intensify secondary flow vortices by 20 %, significantly improving fluid mixing. Notably, incorporating nanoparticles at 4 % concentration boosts heat transfer performance by 30–35 % compared to base fluids, attributed to enhanced thermal conductivity. Additionally, the temperature distribution shows a 15–20 % reduction near the walls relative to the core region, indicating efficient thermal gradient establishment. This work provides novel contributions as the first analytical solution for immiscible nanofluids in curved pipes and quantifies the previously unexplored synergistic effects of curvature and nanoparticles. These findings offer valuable insights for optimizing the design of compact heat exchangers and bioengineered systems, advancing beyond conventional single-fluid approaches in the literature.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101383"},"PeriodicalIF":0.0,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144892520","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}
引用次数: 0
A review of impinging jet ventilation for indoor environment control 冲击射流通风在室内环境控制中的研究进展
International Journal of Thermofluids Pub Date : 2025-08-18 DOI: 10.1016/j.ijft.2025.101384
Arman Ameen , Farhan Lafta Rashid , Mudhar A. Al-Obaidi , Abdallah Bouabidi , Ephraim Bonah Agyekum , Atef Chibani , Mohamed Kezzar
{"title":"A review of impinging jet ventilation for indoor environment control","authors":"Arman Ameen ,&nbsp;Farhan Lafta Rashid ,&nbsp;Mudhar A. Al-Obaidi ,&nbsp;Abdallah Bouabidi ,&nbsp;Ephraim Bonah Agyekum ,&nbsp;Atef Chibani ,&nbsp;Mohamed Kezzar","doi":"10.1016/j.ijft.2025.101384","DOIUrl":"10.1016/j.ijft.2025.101384","url":null,"abstract":"<div><div>Impinging Jet Ventilation (IJV) has emerged as a promising strategy for indoor environmental control, offering an alternative to conventional such as Mixing Ventilation (MV) systems. This review critically examines the performance of IJV in terms of thermal comfort, indoor air quality (IAQ), energy efficiency, and design flexibility, with a broader focus on the system implementation and a particular focus on office environments under moderate heating and cooling loads. The focus of the review is to compare the IJV system with the MV system. In comparison to MV, IJV delivers conditioned air to the occupied zone more effectively by providing stratified, low-mixing airflow and requiring a lower airflow rate to maintain acceptable thermal comfort conditions. This results in improved thermal comfort, reduced energy usage, and enhanced pollutant removal. The system also facilitates thermal stratification and supports higher supply air temperature differentials, allowing for increased energy savings without compromising comfort. The review explores key performance metrics such as Predicted Mean Vote (PMV), Predicted Percentage of Dissatisfied (PPD), draught rate, and ventilation effectiveness, highlighting the conditions under which IJV outperforms MV. Additionally, challenges such as sensitivity to diffuser configuration, nozzle placement, and return vent positioning are addressed. The paper also evaluates recent advancements, including the integration of Internet of Things (IoT) technologies, machine learning, and hybrid systems combining IJV with passive or personalized ventilation. Despite its advantages, IJV remains underutilized due to design complexity and lack of standardizations. To enable broader adoption, future research should focus on simplified modelling tools, performance-based design standards, and scalable applications for various building types. Overall, IJV represents a viable, energy-efficient solution for modern ventilation design, particularly in environments requiring high indoor air quality and localized comfort control.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101384"},"PeriodicalIF":0.0,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144886696","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}
引用次数: 0
Influence of CuO nanoparticles and oil concentration on the thermodynamic properties of R600a during forced boiling convection CuO纳米颗粒和油浓度对R600a强制沸腾对流热力学性质的影响
International Journal of Thermofluids Pub Date : 2025-08-16 DOI: 10.1016/j.ijft.2025.101372
Fernando Toapanta-Ramos , César Nieto-Londoño
{"title":"Influence of CuO nanoparticles and oil concentration on the thermodynamic properties of R600a during forced boiling convection","authors":"Fernando Toapanta-Ramos ,&nbsp;César Nieto-Londoño","doi":"10.1016/j.ijft.2025.101372","DOIUrl":"10.1016/j.ijft.2025.101372","url":null,"abstract":"<div><div>The effects of copper oxide (CuO) nanoparticles and Polyalphaolefin (PAO) lubricating oil on the thermophysical transport parameters of R600a (isobutane) and its flow boiling heat transfer coefficient are evaluated in this work using semi-empirical correlations. Commonly occurring refrigerant–oil mixes in vapor compression refrigeration cycles result from lubrication needs in system components, affecting both transport qualities and heat transfer performance. Considering the effect produced by the heat flows, 10 kW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>, 15 kW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> and 20 kW/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>, to which the fluids are being subjected. This work investigates refrigerant combinations with a maximum nanoparticle–oil ratio of 5% resulting in three formulations: R600a/CuO, R600a/PAO, and R600a/CuO/PAO as modest nanoparticle concentrations can improve these qualities. Key thermal transport parameters, including density, thermal conductivity, dynamic viscosity, and specific heat, show improvement by CuO nanoparticles with oil. Still, the R600a/CuO/PAO mixture shows hardly any variation from pure R600a. The Gungor and Winterton correlation assessed the forced flow boiling heat transfer coefficient. The results reveal that whilst PAO oil reduces the coefficient at 5%, the coefficient rises with increasing concentrations of nanoparticles in the refrigerant. The heat transfer coefficient decreases slightly when both CuO and PAO are present.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101372"},"PeriodicalIF":0.0,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879993","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}
引用次数: 0
Evaluation of a solar flat plate collector's performance using wavy riser tubes and coil inserts 采用波浪上升管和线圈插片的太阳能平板集热器性能评价
International Journal of Thermofluids Pub Date : 2025-08-15 DOI: 10.1016/j.ijft.2025.101378
Lakshmikant Shivanayak , Gowreesh Subramanya S , J S Srikantamurthy , R Thirumaleswara Naik , C.Durga Prasad , Nimona Hailu
{"title":"Evaluation of a solar flat plate collector's performance using wavy riser tubes and coil inserts","authors":"Lakshmikant Shivanayak ,&nbsp;Gowreesh Subramanya S ,&nbsp;J S Srikantamurthy ,&nbsp;R Thirumaleswara Naik ,&nbsp;C.Durga Prasad ,&nbsp;Nimona Hailu","doi":"10.1016/j.ijft.2025.101378","DOIUrl":"10.1016/j.ijft.2025.101378","url":null,"abstract":"<div><div>Solar water heater systems are essential for harnessing renewable solar energy to produce domestic hot water, offering an eco-friendly alternative to traditional heating methods. Flat plate collectors (FPCs), commonly used in solar water heater systems, heavily rely on the effectiveness of the absorber surface to maximize solar energy absorption while minimizing thermal losses. The main aim of this study is to evaluate the performance of flat plate solar collectors. The performance parameters, including Nusselt number and collector efficiency, were examined at different mass flow rates of the working fluid. The assessment of flat plate solar collectors (FPSCs) was performed experimentally and through CFD analysis, utilizing wavy-shaped riser tubes with coil inserts. The experiments involved riser tubes with coil inserts of 10, 20, and 30 mm pitches, with Reynolds numbers ranging from 5500 to 14,500. Compared to plain tubes, the increase in Nusselt number with a 30 mm pitch is 15.38% and 34.48 % at Reynolds numbers of 5500 and 14,500, respectively. For a 10 mm pitch, the Nusselt number increases by 41.02 % and 49.4 % at the same Reynolds numbers. The collector’s efficiency reaches 84 % for a 10 mm pitch at a Reynolds number of 14,500, compared to a plain tube.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101378"},"PeriodicalIF":0.0,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144886793","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}
引用次数: 0
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