International Journal of Thermofluids最新文献

Thermal and solutal analysis of local thermal non-equilibrium effects on gyrotactic microbes in radiative flow of hybrid nanofluid with Soret–Dufour effects 具有Soret-Dufour效应的混合纳米流体辐射流中回旋微生物局部热非平衡效应的热和溶质分析

International Journal of Thermofluids Pub Date : 2025-07-29 DOI: 10.1016/j.ijft.2025.101355

Munawar Abbas , Mostafa Mohamed Okasha , Tatyana Orlova , Ali Akgül , Murad Khan Hassani , Saba Liaqat

{"title":"Thermal and solutal analysis of local thermal non-equilibrium effects on gyrotactic microbes in radiative flow of hybrid nanofluid with Soret–Dufour effects","authors":"Munawar Abbas , Mostafa Mohamed Okasha , Tatyana Orlova , Ali Akgül , Murad Khan Hassani , Saba Liaqat","doi":"10.1016/j.ijft.2025.101355","DOIUrl":"10.1016/j.ijft.2025.101355","url":null,"abstract":"<div><div>The present research investigates the impact of local thermal non-equilibrium on radiative flow of a hybrid nanofluid around a revolving sphere in the presence of gyrotactic microbes and porous medium. To explore heat transfer characteristics in cases where LTE (local thermal equilibrium) is not assumed, the research provides use of a basic mathematical model. In LTNE conditions, the solid and liquid phases experience distinct thermal gradients. SWCNTs (Single-walled carbon nanotubes) and MWCNTs (multi-walled carbon nanotubes) suspended in water make up the hybrid nanofluid under discussion. In order to compare the modified model's heat transfer performance with that of the conventional Hamilton-Crosser model, this study specifically concentrate at the hybrid nanofluid that consists of MWCNTs, SWCNTs, and water. To convert the constitutive equations into ODEs, similarity variables were used. and MATLAB's Bvp4c function has been employed to find solutions. The results suggest that relative to the modified model, classical model can predict increased heat transmission rates with adequate precision. The findings improve the precision of models for thermal conductivity and advance our considerate of the properties of hybrid nanofluid heat transfer. The solid-phase thermal field and the liquid-phase thermal transmission rate both decrease with increasing interphase heat transfer factor in both the modified and classical Hamilton–Crosser models.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101355"},"PeriodicalIF":0.0,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144756748","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

Oil-cooled transformer hot spot temperature reduction using windings height optimum design 油冷变压器热点温度降低采用绕组高度优化设计

International Journal of Thermofluids Pub Date : 2025-07-28 DOI: 10.1016/j.ijft.2025.101353

Mohammad Ali Taghikhani

{"title":"Oil-cooled transformer hot spot temperature reduction using windings height optimum design","authors":"Mohammad Ali Taghikhani","doi":"10.1016/j.ijft.2025.101353","DOIUrl":"10.1016/j.ijft.2025.101353","url":null,"abstract":"<div><div>Transformers are used in transmission and distribution of electrical energy in the power network. Thus, electrical and physical optimization of transformers are important. On the other hand, estimation of the temperature rise and reduction of the hot spot temperature (HST) in a transformer increase the loading capability and life span of the transformer. In this paper, characteristics of an oil-immersed transformer is optimized and minimum losses of the transformer is calculated. For this purpose, the meta-heuristic modified Arctic Puffins optimization (MAPO) algorithm is used to optimize the transformer design. Moreover, temperature distribution in the transformer windings are simulated in different load conditions using a numerical method based on heat transfer theory and heat conduction equation. Besides, the effects of the transformer winding dimensions on the HST are investigated in different load conditions. The results show that the HST value in the windings is minimized at a specific height of the windings. Furthermore, the proposed method for the HST estimation seems to correspond with the results of FEM modeling and measurements in the previous works.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101353"},"PeriodicalIF":0.0,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739568","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

Large-eddy simulations of separated flow and heat transfer in a rib-roughened channel 肋状粗化通道内分离流动和换热的大涡模拟

International Journal of Thermofluids Pub Date : 2025-07-28 DOI: 10.1016/j.ijft.2025.101332

Himani Garg, Christer Fureby

{"title":"Large-eddy simulations of separated flow and heat transfer in a rib-roughened channel","authors":"Himani Garg, Christer Fureby","doi":"10.1016/j.ijft.2025.101332","DOIUrl":"10.1016/j.ijft.2025.101332","url":null,"abstract":"<div><div>Ribbed channel flows play a crucial role in various engineering systems where turbulence enhancement and improved heat transfer are required, such as in turbine blade cooling and combustor wall applications. Numerical simulations have emerged as an essential tool for analyzing the intricate turbulence dynamics and flow separation phenomena, which are fundamental for optimizing the channel performance. This work presents a comparative analysis of turbulence modeling approaches, specifically Reynolds-Averaged Navier–Stokes (RANS) and Large Eddy Simulations (LES), using OpenFOAM across Reynolds numbers of 4000, 8000, 12000, 16000, 22000, and 24000. Multiple turbulence models, subgrid-scale models, and mesh resolutions are examined to assess their influence on the accuracy of flow and thermal transfer predictions. The numerical results, particularly in terms of turbulence characterization and its effect on thermal performance, are validated against the experimental data of Wang (2007). The mesh sizes vary between 1 and 25 million cells, capturing around 90% of the turbulent energy, suggesting that the LES meshes provide sufficient resolution. Overall, LES results exhibit stronger agreement with experimental observations compared to RANS predictions, with WALE and LDKM subgrid models demonstrating superior performance relative to SMG and OEEVM. Additionally, to deepen the understanding of turbulence mechanisms governing flow separation, reattachment, and eventually redevelopment, we present extensive analyses of flow parameters, e.g., mean velocity, friction coefficient and Reynolds shear stress. The anisotropic characteristics of turbulence at all scales are examined using anisotropic invariant maps, revealing substantial variations in anisotropy across different near-wall regions between consecutive ribs.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101332"},"PeriodicalIF":0.0,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722725","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

Evaluating the viscous dissipation effect on dusty boger hybrid nanofluid with applications of cattaneo-christov approach: Xue and Yamada–Ota models 应用cattaneo-christov方法评价灰泥混合纳米流体的粘性耗散效应：Xue和Yamada-Ota模型

International Journal of Thermofluids Pub Date : 2025-07-26 DOI: 10.1016/j.ijft.2025.101350

Munawar Abbas , Mostafa Mohamed Okasha , Barno Abdullaeva , Jihad Younis , Mohammed Tharwan , Saba Liaqat

{"title":"Evaluating the viscous dissipation effect on dusty boger hybrid nanofluid with applications of cattaneo-christov approach: Xue and Yamada–Ota models","authors":"Munawar Abbas , Mostafa Mohamed Okasha , Barno Abdullaeva , Jihad Younis , Mohammed Tharwan , Saba Liaqat","doi":"10.1016/j.ijft.2025.101350","DOIUrl":"10.1016/j.ijft.2025.101350","url":null,"abstract":"<div><div>This study aims to investigate the effects of viscous dissipation on the flow of a dusty Boger hybrid nanofluid over a plate using variable thermal conductivity and the CattaneoChristov heat flux model. The goal of this work is to use sodium alginate fluids to determine the hybrid nanofluid's thermal mobility. For the thermal behaviour, <em>Cu</em> and A<em>l</em><sub>2</sub>O<sub>3</sub> are used as the nanoparticles. It is particularly useful in industrial processes including polymeric and non-Newtonian fluids, such as in extrusion, chemical processing, cooling of electronic equipment, and thermal management in energy systems. The inclusion of hybrid nanoparticles enhances thermal performance, while the consideration of thermal relaxation effects via the CattaneoChristov model makes the analysis more realistic for high-temperature and microscale applications. Moreover, the presence of dust particles adds relevance to areas like aerospace engineering, combustion systems, and particulate-laden flows in environmental and biomedical fields. An appropriate transformation strategy is applied to transform PDEs into ODEs. The shooting method is used to establish the numerical solution. The results demonstrate that the Boger hybrid nanofluid displays an improved flow field and a lowering liquid phase thermal field for higher values of the solvent fraction factor.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101350"},"PeriodicalIF":0.0,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144757362","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

An optimized cubic B-spline algorithm for high-precision approximation of nonlinear transport phenomena 高精度逼近非线性输运现象的优化三次b样条算法

International Journal of Thermofluids Pub Date : 2025-07-24 DOI: 10.1016/j.ijft.2025.101331

Rabia Noureen , Muhammad Kashif Iqbal , Maryam Asgir , Bandar Almohsen , Muhammad Azeem , Husam A. Neamah

{"title":"An optimized cubic B-spline algorithm for high-precision approximation of nonlinear transport phenomena","authors":"Rabia Noureen , Muhammad Kashif Iqbal , Maryam Asgir , Bandar Almohsen , Muhammad Azeem , Husam A. Neamah","doi":"10.1016/j.ijft.2025.101331","DOIUrl":"10.1016/j.ijft.2025.101331","url":null,"abstract":"<div><div>This study aims to investigate a numerical scheme based on etics, Riphah Internatxtended cubic B-spline functions for solving the nonlinear gas dynamics equation, which plays a crucial role in the study of physical phenomena such as explosions, combustion, detonation and condensation within moving flows. The standard finite difference formulation has been employed to approximate the time derivative, while the solution curve in spatial direction is interpolated using extended cubic B-spline functions. A comprehensive stability analysis of the scheme is provided to ensure that errors do not propagate over time. Additionally, a convergence analysis for cubic B-spline interpolation is conducted to assess the accuracy of the solution. The effectiveness and efficiency of the proposed method are tested through numerical simulations. The findings indicate that the proposed technique provides better error estimates compared to other methods discussed in the literature. The straightforward algorithm, high accuracy and minimal computational efforts are the major advantages of this approach. Therefore, the proposed method may serve as a promising and efficient alternative for the numerical solution of nonlinear partial differential equations.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101331"},"PeriodicalIF":0.0,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713901","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

Jeffrey fluids heat-mass transfer analysis through porous medium by utilizing Yang-Abdel-Cattani operator 利用Yang-Abdel-Cattani算子分析多孔介质中杰弗里流体的热质传递

International Journal of Thermofluids Pub Date : 2025-07-23 DOI: 10.1016/j.ijft.2025.101339

Sehra , Mehwish Shafat , Ilyas Khan

引用次数: 0

Energy and exergy analysis of PCM-based pyramid solar still 基于pcm的金字塔太阳能蒸馏器的能量和火用分析

International Journal of Thermofluids Pub Date : 2025-07-23 DOI: 10.1016/j.ijft.2025.101349

Safa M. Aldarabseh , Salah Abdallah

{"title":"Energy and exergy analysis of PCM-based pyramid solar still","authors":"Safa M. Aldarabseh , Salah Abdallah","doi":"10.1016/j.ijft.2025.101349","DOIUrl":"10.1016/j.ijft.2025.101349","url":null,"abstract":"<div><div>Sustainable and effective desalination technologies are required to meet the growing demand for drinkable water worldwide. The intermittent nature of solar desalination necessitates the use of efficient thermal energy storage materials (TESMs) to prolong operation past the hours of sunshine. To improve desalination performance, this study introduces a modified stepped pyramid solar still (SSP) that incorporates phase change materials (PCMs), hollow rectangular fins, and electrical heaters driven by photovoltaic energy. In comparison to a traditional solar still, the system was tested both conceptually and experimentally in five different configurations (CSS, SSP, SSP with electrical heaters (SSE), SSP with paraffin wax and hollow rectangular fins (SSM), and SSM with electrical heaters (SSME)) during the winter, spring, and summer seasons. The findings showed that, in comparison to the CSS, the productivity, energy, and exergy efficiency of SSP in the winter and spring increased on average by 109.47 % and 204.91 %, 28.44 % and 31.68 %, and 10.21 % and 18.15 %, respectively. While the productivity, energy and exergy efficiency of SSE3 was augmented over CSS on average by 266.62 %, 45.64 %, and 23.45 %, respectively. Furthermore, the productivity energy and exergy efficiency of SSM increased over CSS on average by 431.13 %, 70.67 % and 41.5 %, respectively. SSME obtained the highest performance, with an average increase in productivity of 675.2 %, energy efficiency of 78.77 %, and exergy efficiency of 48.97 %. To simulate saline water temperature fluctuations, a thorough heat balance study was carried out, and theoretical predictions and practical observations closely matched within acceptable error range between 0.76–18. The results demonstrate how PCM-enhanced solar stills can be used for high-efficiency, sustainable water desalination, providing a workable option for areas with low access to freshwater.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101349"},"PeriodicalIF":0.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739567","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

Predicting and optimizing the wet outer surface of water-sprayed finned-tube air-cooled condensers based on purely geometric arguments for inclined sprays: Application on heat transfer enhancement for the cooling of the refrigerant R134a 基于倾斜喷雾纯几何参数的喷水翅片管风冷冷凝器湿外表面预测与优化：在R134a冷媒强化传热中的应用

International Journal of Thermofluids Pub Date : 2025-07-21 DOI: 10.1016/j.ijft.2025.101347

Ibra Bop , Biram Dieng , Senghane Mbodji , Gorgui Bop , Ababacar Thiam

{"title":"Predicting and optimizing the wet outer surface of water-sprayed finned-tube air-cooled condensers based on purely geometric arguments for inclined sprays: Application on heat transfer enhancement for the cooling of the refrigerant R134a","authors":"Ibra Bop , Biram Dieng , Senghane Mbodji , Gorgui Bop , Ababacar Thiam","doi":"10.1016/j.ijft.2025.101347","DOIUrl":"10.1016/j.ijft.2025.101347","url":null,"abstract":"<div><div>During spray cooling, the determination of the heat energy gains due to water collection requires prior knowledge of the heater wetted surface. However, it is impossible to directly measure this surface, especially for complex geometries like finned-tube heat exchangers. In this paper, a model based on purely geometric arguments is proposed for the prediction of the wet outer surface of a water-sprayed finned-tube air-cooled condenser for an inclined spray. It is based on determining the number of wetted fins and tubes in the spray impact area and deduce therefrom the heater total wetted surface. Then, to understand the mechanism of spray cooling by examining the effects of spray inclination on heat transfers, the model is applied to the cooling of the refrigerant R134a. The results showed that the optimal horizontal spray inclination angle is 45° and increasing this angle from 0 to 45° allowed the wet surface to grow from 0.043 to 0.091 m<sup>2</sup>. At <em>β</em> = 45°, the wet surface equalizes the spray impact area while the water collection rate tends to unity, which helped to intensify heat transfers from 1.718 to 1.744. Consequently, the refrigerant condensing temperature drops from 25.5 to 23.5 °C when <em>β</em> is varied from 0 to 45° and from 40 to 23.5 °C when mist is applied with 45° of inclination compared to the heater without mist. It is concluded that spray inclination allows to reduce the condenser vacuum rate and increase the water collection rate, which results in an enhancement in the condenser heat dissipation.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101347"},"PeriodicalIF":0.0,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696460","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

International Journal of Thermofluids Pub Date : 2025-07-21 DOI: 10.1016/j.ijft.2025.101346

Muhammad Hamza , Dil Nawaz khan Marwat , Azhar Ali

{"title":"New similarity solutions of heat and mass transfer in flow of Carreau fluid over a rough sheet with nonlinear kinematics","authors":"Muhammad Hamza , Dil Nawaz khan Marwat , Azhar Ali","doi":"10.1016/j.ijft.2025.101346","DOIUrl":"10.1016/j.ijft.2025.101346","url":null,"abstract":"<div><div>This research introduces novel and generalized similarity solutions for heat and mass transfer in the flow of Carreau fluid across a rough, non-flat sheet characterized by nonlinear kinematics. Previous research presented space-dependent parameters, particularly Weissenberg numbers, within the transformed ordinary differential equation systems, which is against the spirit of the fundamental principle of similarity solutions. By creating a mathematically consistent transformation, we overcome this significant issues and produce a more comprehensive and precise modelling framework. MATLAB's bvp4c approach is used to numerically solve the governing equations. Important dimensionless factors are examined in relation to velocity, temperature, concentration, and skin friction, including the Weissenberg number, non-linear kinematics, power-law index, Prandtl number, Schmidt number, and surface roughness. Notably, we discover that while raising the Weissenberg number thickens the velocity boundary layer in shear-thickening fluids, surface roughness and sheet temperature greatly increase the mass transfer rate. These findings provide new perspectives for non-Newtonian thermal processing systems, coating processes, and biomedical transport applications.</div></div>","PeriodicalId":36341,"journal":{"name":"International Journal of Thermofluids","volume":"29 ","pages":"Article 101346"},"PeriodicalIF":0.0,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722724","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

Innovative 3D numerical study of a catalyst bed and comparison with previous 2D and experimental studies 创新的催化剂床的三维数值研究，并与以往的二维和实验研究的比较

International Journal of Thermofluids Pub Date : 2025-07-19 DOI: 10.1016/j.ijft.2025.101344

M.H. Mansuri Mughari , H. Naseh , S. Noori

引用次数: 0