International Journal of Numerical Methods for Heat & Fluid Flow最新文献

{"title":"Nacelle optimisation through multi-fidelity neural networks","authors":"Francisco Sánchez-Moreno, David MacManus, Fernando Tejero, Christopher Sheaf","doi":"10.1108/hff-12-2023-0745","DOIUrl":"https://doi.org/10.1108/hff-12-2023-0745","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>Aerodynamic shape optimisation is a complex problem usually governed by transonic non-linear aerodynamics, a high dimensional design space and high computational cost. Consequently, the use of a numerical simulation approach can become prohibitive for some applications. This paper aims to propose a computationally efficient multi-fidelity method for the optimisation of two-dimensional axisymmetric aero-engine nacelles.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The nacelle optimisation approach combines a gradient-free algorithm with a multi-fidelity surrogate model. Machine learning based on artificial neural networks (ANN) is used as the modelling technique because of its ability to handle non-linear behaviour. The multi-fidelity method combines Reynolds-averaged Navier Stokes and Euler CFD calculations as high- and low-fidelity, respectively.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>Ratios of low- and high-fidelity training samples to degrees of freedom of n_LF/n_DOFs = 50 and n_HF/n_DOFs = 12.5 provided a surrogate model with a root mean squared error less than 5% and a similar convergence to the optimal design space when compared with the equivalent CFD-in-the-loop optimisation. Similar nacelle geometries and aerodynamic flow topologies were obtained for down-selected designs with a reduction of 92% in the computational cost. This highlights the potential benefits of this multi-fidelity approach for aerodynamic optimisation within a preliminary design stage.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>The application of a multi-fidelity technique based on ANN to the aerodynamic shape optimisation problem of isolated nacelles is the key novelty of this work. The multi-fidelity aspect of the method advances current practices based on single-fidelity surrogate models and offers further reductions in computational cost to meet industrial design timescales. Additionally, guidelines in terms of low- and high-fidelity sample sizes relative to the number of design variables have been established.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"103 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isogeometric collocation method to simulate phase-field crystal model","authors":"Reza Masoumzadeh, Mostafa Abbaszadeh, Mehdi Dehghan","doi":"10.1108/hff-01-2024-0020","DOIUrl":"https://doi.org/10.1108/hff-01-2024-0020","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>The purpose of this study is to develop a new numerical algorithm to simulate the phase-field model.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>First, the derivative of the temporal direction is discretized by a second-order linearized finite difference scheme where it conserves the energy stability of the mathematical model. Then, the isogeometric collocation (IGC) method is used to approximate the derivative of spacial direction. The IGC procedure can be applied on irregular physical domains. The IGC method is constructed based upon the nonuniform rational B-splines (NURBS). Each curve and surface can be approximated by the NURBS. Also, a map will be defined to project the physical domain to a simple computational domain. In this procedure, the partial derivatives will be transformed to the new domain by the Jacobian and Hessian matrices. According to the mentioned procedure, the first- and second-order differential matrices are built. Furthermore, the pseudo-spectral algorithm is used to derive the first- and second-order nodal differential matrices. In the end, the Greville Abscissae points are used to the collocation method.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>In the numerical experiments, the efficiency and accuracy of the proposed method are assessed through two examples, demonstrating its performance on both rectangular and nonrectangular domains.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>This research work introduces the IGC method as a simulation technique for the phase-field crystal model.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"72 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconciliation of wire woven mesh porous media in controlling the desired heat transfer and pressure drop","authors":"Trilok G., N. Gnanasekaran, Moghtada Mobedi","doi":"10.1108/hff-01-2024-0014","DOIUrl":"https://doi.org/10.1108/hff-01-2024-0014","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>Despite the reputation of the metal-based porous media for their ability to augment heat transfer as widely witnessed in the literature and practically operating heat exchanging applications, the coexisting penalty of the increased pressure drop demanding increased pumping power poses a major concern that invites the need for an alternate solution to handle this unsought outcome. Therefore, this study aims at providing a better solution to the existing cost and benefit scenarios to benefit a plethora of engineering applications including energy transfer, energy storage and energy conversion.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>This work highlights on the property of stacked woven wire mesh porous media such as their stacking types, porous conditions and thickness scenarios that can potentially result in distinct trade-off scenarios. A vertical channel is numerical modelled by using REV scaled modelling technique using Darcy-Forchheimer and local thermal non-equilibrium models to illustrate the possibilities of this variety of trade off scenarios between the desirable heat transfer and the unsought flow resistance.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>This work illustrates the advantages of wire mesh-based porous medium and its distinct potential in controlling the existing trade-offs between the cost and benefit aspects. It is found that by varying the features of wire mesh porous media, the interplay between the conflictingly existing characteristics can be much easily handled specific to distinct requirements associated with variety of engineering applications.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>The study emphasizes on a new solution or methodology to handle the penalty of pressure drop associated with metal-based porous media. Through this study, a novel approach to control the ultimately costing pumping power at the benefit of increased heat transfer is provided considering various requirements that could be associated with any thermal management systems. Various possibilities and potentials of wire mesh porous media are illustrated highlighting on their benefit of ease with which the mentioned goals can be achieved.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"306 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerodynamic discrepancies of high-speed trains meeting within two types noise barriers: considering modeling scale ratio","authors":"Wei-Chao Yang, Guo-Zhi Li, E Deng, De-Hui Ouyang, Zhi-Peng Lu","doi":"10.1108/hff-02-2024-0153","DOIUrl":"https://doi.org/10.1108/hff-02-2024-0153","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>Sustainable urban rail transit requires noise barriers. However, these barriers’ durability varies due to the differing aerodynamic impacts they experience. The purpose of this paper is to investigate the aerodynamic discrepancies of trains when they meet within two types of rectangular noise barriers: fully enclosed (FERNB) and semi-enclosed with vertical plates (SERNBVB). The research also considers the sensitivity of the scale ratio in these scenarios.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>A 1:16 scaled moving model test analyzed spatiotemporal patterns and discrepancies in aerodynamic pressures during train meetings. Three-dimensional computational fluid dynamics models, with scale ratios of 1:1, 1:8 and 1:16, used the improved delayed detached eddy simulation turbulence model and slip grid technique. Comparing scale ratios on aerodynamic pressure discrepancies between the two types of noise barriers and revealing the flow field mechanism were done. The goal is to establish the relationship between aerodynamic pressure at scale and in full scale.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>The aerodynamic pressure on SERNBVB is influenced by the train’s head and tail waves, whereas for FERNB, it is affected by pressure wave and head-tail waves. Notably, SERNBVB's aerodynamic pressure is more sensitive to changes in scale ratio. As the scale ratio decreases, the aerodynamic pressure on the noise barrier gradually increases.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>A train-meeting moving model test is conducted within the noise barrier. Comparison of aerodynamic discrepancies during train meets between two types of rectangular noise barriers and the relationship between the scale and the full scale are established considering the modeling scale ratio.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"9 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of reflection of wave propagation in magneto-thermoelastic nonlocal micropolar orthotropic medium at impedance boundary","authors":"Anand Kumar Yadav, Hari Shankar Mahato, Sangeeta Kumari, Pawel Jurczak","doi":"10.1108/hff-02-2024-0095","DOIUrl":"https://doi.org/10.1108/hff-02-2024-0095","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>This study aims to examine the plane wave reflection problem in micropolar orthotropic magneto-thermoelastic half space, considering the influence of impedance as a boundary in a nonlocal elasticity.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>This study presents the novel formulation of governing partial differential equations for micropolar orthotropic medium with impact of nonlocal thermo-elasticity under magnetic field.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>This study provides the numerical results validation for a particular numerical data and expression for the amplitude ratios of reflected waves and identifies the existence of four different waves, namely, quasi longitudinal displacement <span>\u0000<mml:math display=\"inline\" xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mrow><mml:mi>q</mml:mi><mml:mi>C</mml:mi><mml:mi>L</mml:mi><mml:mi>D</mml:mi></mml:mrow></mml:math></span>-wave, quasi thermal wave <span>\u0000<mml:math display=\"inline\" xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mrow><mml:mi>q</mml:mi><mml:mi>C</mml:mi><mml:mi>T</mml:mi></mml:mrow></mml:math></span>-wave, quasi transverse displacement <span>\u0000<mml:math display=\"inline\" xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mrow><mml:mi>q</mml:mi><mml:mi>C</mml:mi><mml:mi>T</mml:mi><mml:mi>D</mml:mi></mml:mrow></mml:math></span>-wave and quasi-transverse micro-rotational <span>\u0000<mml:math display=\"inline\" xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mrow><mml:mi>q</mml:mi><mml:mi>C</mml:mi><mml:mi>T</mml:mi><mml:mi>M</mml:mi></mml:mrow></mml:math></span>-wave. The study derives the velocity equation giving the speed and phase velocity of these waves. The study also shows that the small-scale size effect gives significant impact on phase velocity.</p><!--/ Abstract__block -->\u0000<h3>Research limitations/implications</h3>\u0000<p>The graphical analysis examines the variation of speeds and coefficients of attenuation of these waves due to frequency, magnetic field and nonlocal parameters. Also, significant conclusions on the variation of reflection coefficient against nonlocal parameter, frequency, impedance parameter and angle of incidence are provided graphically.</p><!--/ Abstract__block -->\u0000<h3>Practical implications</h3>\u0000<p>The creation of more effective micropolar orthotropic anisotropic materials which are very useful in the daily life and their applications in earth science are greatly impacted by the findings of this study.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>The authors of the submitted document initiated and produced it collectively, with equal contributions from all members.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"35 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141726176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of activation energy and cross-diffusion effects on 3D convective rotating nanoliquid flow in a non-Darcy porous medium","authors":"Sivasankaran Sivanandam, Turki J. Alqurashi, Hashim M. Alshehri","doi":"10.1108/hff-01-2024-0008","DOIUrl":"https://doi.org/10.1108/hff-01-2024-0008","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>This study aims to investigate numerically the impact of the three-dimensional convective nanoliquid flow on a rotating frame embedded in the non-Darcy porous medium in the presence of activation energy. The cross-diffusion effects, i.e. Soret and Dufour effects, and heat generation are included in the study. The convective heating condition is applied on the bounding surface.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The control model consisted of a system of partial differential equations (PDE) with boundary constraints. Using suitable similarity transformation, the PDE transformed into an ordinary differential equation and solved numerically by the Runge–Kutta–Fehlberg method. The obtained results of velocity, temperature and solute concentration characteristics plotted to show the impact of the pertinent parameters. The heat and mass transfer rate and skin friction are also calculated.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>It is found that both Biot numbers enhance the heat and mass distribution inside the boundary layer region. The temperature increases by increasing the Dufour number, while concentration decreases by increasing the Dufour number. The heat transfer is increased up to 8.1% in the presence of activation energy parameter (<em>E</em>). But, mass transfer rate declines up to 16.6% in the presence of <em>E</em>.</p><!--/ Abstract__block -->\u0000<h3>Practical implications</h3>\u0000<p>The applications of combined Dufour and Soret effects are in separation of isotopes in mixture of gases, oil reservoirs and binary alloys solidification. The nanofluid with porous medium can be used in chemical engineering, heat exchangers and nuclear reactor.</p><!--/ Abstract__block -->\u0000<h3>Social implications</h3>\u0000<p>This study is mainly useful for thermal sciences and chemical engineering.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>The uniqueness in this research is the study of the impact of activation energy and cross-diffusion on rotating nanoliquid flow with heat generation and convective heating condition. The obtained results are unique and valuable, and it can be used in various fields of science and technology.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"1 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141608157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MHD conjugate mixed convection along with internal heat generation and Joule heating in a closed/open cavity with rotating solid cylinder","authors":"Nahid Hasan, Sumon Saha","doi":"10.1108/hff-01-2024-0054","DOIUrl":"https://doi.org/10.1108/hff-01-2024-0054","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>This study aims to investigate magnetohydrodynamic (MHD) conjugate pure mixed convection considering interior heat production and resistive heating inside a square closed/open cavity featuring a rotating cylinder for aiding (clockwise) and opposing (counterclockwise) flow configurations. Moreover, the impacts of altering cylinder size and conductivity on the system’s overall performance to determine optimum conditions are examined in this investigation.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The closed chamber is differentially heated by keeping high and low temperatures at the vertical boundaries. In contrast, the open cavity has a heated left wall and an open right boundary. The Galerkin finite element method is used to solve the Navier–Stokes and the thermal energy equations, which construct the present study’s mathematical framework. Numerical simulations are conducted for the specified ranges of several controlling parameters: Reynolds (31.62 ≤ <em>Re</em> ≤ 1000), Grashof (10³ ≤ <em>Gr</em> ≤ 10⁶) and Hartmann numbers (0 ≤ <em>Ha</em> ≤ 31.62), and volumetric heat generation coefficient (Δ = 0, 3).</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>When <em>Gr</em>, <em>Re</em> and <em>Ha</em> simultaneously increase, the average Nusselt number along the warmed boundary rises accordingly. Conversely, interior heat production lowers heat transmission within the computational domain, which is also monitored regarding mean fluid temperature, overall entropy production and thermal performance criterion. Finally, the open cavity confirms better thermal performance than the closed cavity.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>Comprehending the impacts of the magnetic field, Joule heating, internal heat generation and enclosed or open boundary on pure MHD combined free-forced convective flow offers valuable understandings of temperature fluctuations, velocity propagations, heat transport and irretrievable energy loss in numerous engineering applications.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"62 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141597316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Convective heat transfer with Hall current using magnetized non-Newtonian Carreau fluid model on the cilia-attenuated flow","authors":"Fehid Ishtiaq, R. Ellahi, M.M. Bhatti, Sadiq M. Sait","doi":"10.1108/hff-03-2024-0181","DOIUrl":"https://doi.org/10.1108/hff-03-2024-0181","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>Cilia serves numerous biological functions in the human body. Malfunctioning of nonmotile or motile cilia will have different kinds of consequences for human health. More specifically, the directed and rhythmic beat of motile cilia facilitates the unidirectional flow of fluids that are crucial in both homeostasis and the development of ciliated tissues. In cilia-dependent hydrodynamic flows, tapering geometries look a lot like the structure of biological pathways and vessels, like airways and lymphatic vessels. In this paper, the Carreau fluid model through the cilia-assisted tapered channel (asymmetric) under the influence of induced magnetic field and convective heat transfer is investigated.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>Lubrication theory is a key player in the mathematical formulation of momentum, magnetic field and energy equations. The formulated nonlinear and coupled differential equations are solved with the aid of the homotopy perturbation method (HPM). The graphical results are illustrated with the help of the computational software “Mathematica.”</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>The impact of diverse emerging physical parameters on velocity, induced magnetic field, pressure rise, current density and temperature profiles is presented graphically. It is observed that the cilia length parameter supported the velocity and current density profiles, while the Hartman number and Weissenberg number were opposed. A promising effect of emerging parameters on streamlines is also perceived.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>The study provides novel aspects of cilia-driven induced magnetohydrodynamics flow of Carreau fluid under the influence of induced magnetic field and convective heat transfer through the asymmetric tapered channel.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"46 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141597317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-Fourier computations of heat and mass transport in nanoscale solid-fluid interactions using the Galerkin finite element method","authors":"Abdulaziz Alsenafi, Fares Alazemi, M. Nawaz","doi":"10.1108/hff-02-2024-0119","DOIUrl":"https://doi.org/10.1108/hff-02-2024-0119","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>To improve the thermal performance of base fluid, nanoparticles of three types are dispersed in the base fluid. A novel theory of non-Fourier heat transfer is used for design and development of models. The thermal performance of sample fluids is compared to determine which types of combination of nanoparticles are the best for an optimized enhancement in thermal performance of fluids. This article aims to: (i) investigate the impact of nanoparticles on thermal performance; and (ii) implement the Galerkin finite element method (GFEM) to thermal problems.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The mathematical models are developed using novel non-Fourier heat flux theory, conservation laws of computational fluid dynamics (CFD) and no-slip thermal boundary conditions. The models are approximated using thermal boundary layer approximations, and transformed models are solved numerically using GFEM. A grid-sensitivity test is performed. The accuracy, correction and stability of solutions is ensured. The numerical method adopted for the calculations is validated with published data. Quantities of engineering interest, i.e. wall shear stress, wall mass flow rate and wall heat flux, are calculated and examined versus emerging rheological parameters and thermal relaxation time.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>The thermal relaxation time measures the ability of a fluid to restore its original thermal state, called thermal equilibrium and therefore, simulations have shown that the thermal relaxation time associated with a mono nanofluid has the most substantial effect on the temperature of fluid, whereas a ternary nanofluid has the smallest thermal relaxation time. A ternary nanofluid has a wider thermal boundary thickness in comparison with base and di- and mono nanofluids. The wall heat flux (in the case of the ternary nanofluids) has the most significant value compared with the wall shear stresses for the mono and hybrid nanofluids. The wall heat and mass fluxes have the highest values for the case of non-Fourier heat and mass diffusion compared to the case of Fourier heat and mass transfer.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>An extensive literature review reveals that no study has considered thermal and concentration memory effects on transport mechanisms in fluids of cross-rheological liquid using novel theory of heat and mass [presented by Cattaneo (Cattaneo, 1958) and Christov (Christov, 2009)] so far. Moreover, the finite element method for coupled and nonlinear CFD problems has not been implemented so far. To the best of the authors’ knowledge for the first time, the dynamics of wall heat flow rate and mass flow rate under simultaneous effects of thermal and solute relaxation times, Ohmic dissipation and first-order chemical reactions are studied.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"51 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141584213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation of natural convection in a differentially heated cubical cavity with solid fins","authors":"Xuan Hoang Khoa Le, Hakan F. Öztop, Mikhail A. Sheremet","doi":"10.1108/hff-11-2023-0698","DOIUrl":"https://doi.org/10.1108/hff-11-2023-0698","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>The performance of solid fins inside a differentially heated cubical cavity is numerically studied in this paper. The main purpose of the study is to make an optimization to reach the maximum heat transfer in the enclosure having the solid fins with studied parameters.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The considered domain of interest is a differentially heated cube having heat-conducting solid fins placed on the heated wall while an opposite wall is a cooled one. Other walls are adiabatic. Governing equations describing natural convection in the fluid filled cube and heat conduction in solid fins have been written using non-dimensional variables such velocity and vorticity taking into account the Boussinesq approximation for the buoyancy force and ideal solid/fluid interfaces between solid fins and fluid. The formulated equations with appropriate initial and boundary conditions have been solved by the finite difference method of the second of accuracy. The developed in-house computational code has been validated using the mesh sensitivity analysis and numerical data of other authors. Analysis has been performed in a wide range of key parameters such as Rayleigh number (<em>Ra</em> = 10⁴–10⁶), non-dimensional fins length (<em>l</em> = 0.2–0.8), non-dimensional location of fins (<em>d</em> = 0.2–0.6) and number of fins (<em>n</em> = 1–3).</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>From numerical methods point of view the used non-primitive variables allows to perform numerical simulation of convective heat transfer in three-dimensional (3D) regions with two advantages, namely, excluding difficulties that can be found using vector potential functions and reducing the computational time compared to primitive variables and SIMPLE-like algorithms. From a physical point of view, it has been shown that using solid fins can intensify the heat transfer performance compared to cavities without any fins. Fins located close to the bottom wall of the cavity have a better heat transfer rate than those placed close to the upper cavity surface. At high Rayleigh numbers, increasing the fins length beyond 0.6 leads to a reduction of the average Nusselt number, and one solid fin can be used to intensify the heat transfer.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>The present numerical study is based on hybrid approach for numerical analysis of convective heat transfer using velocity and vorticity that has some mentioned advantages. Obtained results allow intensifying the heat transfer using solid fins in 3D chambers with appropriate location and length.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"25 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141566099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}