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

{"title":"Numerical investigation of two-dimensional fractional Helmholtz equation using Aboodh transform scheme","authors":"Muhammad Nadeem, Mohamed Sharaf, Saipunidzam Mahamad","doi":"10.1108/hff-07-2024-0543","DOIUrl":"https://doi.org/10.1108/hff-07-2024-0543","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>This paper aims to present a numerical investigation for two-dimensional fractional Helmholtz equation using the Aboodh integral homotopy perturbation transform scheme (AIHPTS).</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The proposed scheme combines the Aboodh integral transform and the homotopy perturbation scheme (HPS). This strategy is based on an updated form of Taylor’s series that yields a convergent series solution. This study analyzes the fractional derivatives in the context of Caputo.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>This study illustrates two numerical examples and calculates their approximate results using AIHPTS. The derived findings are also presented in tabular form and graphical representations.</p><!--/ Abstract__block -->\u0000<h3>Research limitations/implications</h3>\u0000<p>In addition, He’s polynomials are calculated using HPS, so the minimal computational outcome is a defining feature of this method and gives a competitive advantage over other series solution techniques.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>Numerical data and graphical illustrations for different fractional order levels confirm the proposed method’s successful performance. The results show that the proposed approach is speedy and straightforward to execute on fractional-ordered models.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"103 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536405","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":"Nanofluid effect on dual-flow parabolic trough collector performance accompanies with passive technique using experimental data","authors":"Ali Akbar Abbasian Arani, Ali Memarzadeh","doi":"10.1108/hff-03-2024-0247","DOIUrl":"https://doi.org/10.1108/hff-03-2024-0247","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>Using passive techniques like twisted tapes and corrugated surface is an efficient method of heat transfer improvement, since the referred manners break the boundary layer and improve the heat exchange. This paper aims to present an improved dual-flow parabolic trough collector (PTC). For this purpose, the effect of an absorber roof, a type of turbulator and a grooved absorber tube in the presence of nanofluid is investigated separately and simultaneously.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The FLUENT was used for solution of governing equation using control volume scheme. The control volume scheme has been used for solving the governing equations using the finite volume method. The standard k–e turbulence model has been chosen.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>Fluid flow and heat transfer features, as friction factor, performance evaluation criteria (PEC) and Nusselt number have been calculated and analyzed. It is showed that absorber roof intensifies the heat transfer ratio in PTCs. Also, the combination of inserting the turbulator, outer corrugated and inner grooved absorber tube surface can enhance the PEC of PTCs considerably.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>Results of the current study show that the PTC with two heat transfer fluids, outer and inner surface corrugated absorber tube, inserting the twisted tape and absorber roof have the maximum Nusselt number ratio equal to 5, and PEC higher than 2.5 between all proposed arrangements for investigated Reynolds numbers (from 10,000 to 20,000) and nanoparticles [Boehmite alumina (“λ-AlOOH)”] volume fractions (from 0.005 to 0.03). Maximum Nusselt number and PEC correspond to nanoparticle volume fraction and Reynolds number equal to 0.03 and 20,000, respectively. Besides, it was found that the performance evaluation criteria index values continuously grow by an intensification of nanoparticle volume concentrations.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"3 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486711","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":"A numerical study of double flow focusing micro-jets","authors":"Rizwan Zahoor, Saša Bajt, Božidar Šarler","doi":"10.1108/hff-07-2024-0480","DOIUrl":"https://doi.org/10.1108/hff-07-2024-0480","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>Double flow-focusing nozzles (DFFNs) form a coaxial flow of primary liquid with micro-crystalline samples, surrounded by secondary liquid and focusing gas. This paper aims to develop an experimentally validated numerical model and assess the performance of micro-jets from a DFFN as a function of various operating parameters for the water–ethanol–helium system, revealing the jet's stability, diameter, length and velocity.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The physical model is formulated in the mixture-continuum formulation, which includes coupled mass, momentum and species transport equations. The model is numerically formulated within the finite volume method–volume of fluid approach and implemented in OpenFOAM to allow for a non-linear variation of the fluid's material properties as a function of the mixture concentration. The numerical results are compared with the experimental data.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>A sensitivity study of jets with Reynolds numbers between 12 and 60, Weber numbers between 4 and 120 and capillary numbers between 0.2 and 2.0 was performed. It was observed that jet diameters and lengths get larger with increased primary and secondary fluid flow rates. Increasing gas flow rates produces thinner, shorter and faster jets. Previously considered pre-mixed and linear mixing models substantially differ from the accurate representation of the water–ethanol mixing dynamics in DFFNs. The authors demonstrated that Jouyban–Acree mixing model fits the experimental data much better.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>The mixing of primary and secondary liquids in the jet produced by DFFN is numerically modelled for the first time. This study provides novel insights into mixing dynamics in such micro-jets, which can be used to improve the design of DFFNs.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"86 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486730","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":"Comparative analysis of buoyancy-driven hydromagnetic flow and heat transfer in a partially heated square enclosure using Cu-Fe3O4 and MoS2-Fe3O4 nanofluids","authors":"N. Ameer Ahammad","doi":"10.1108/hff-06-2024-0415","DOIUrl":"https://doi.org/10.1108/hff-06-2024-0415","url":null,"abstract":"&lt;h3&gt;Purpose&lt;/h3&gt;\u0000&lt;p&gt;This study aims to investigate entropy generation through natural convection and examine heat transfer properties within a partially heated and cooled enclosure influenced by an angled magnetic field. The enclosure, subjected to consistent heat production or absorption, contains a porous medium saturated with a hybrid nanofluid blend of Cu-Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; and MoS&lt;sub&gt;2&lt;/sub&gt;-Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt;.&lt;/p&gt;&lt;!--/ Abstract__block --&gt;\u0000&lt;h3&gt;Design/methodology/approach&lt;/h3&gt;\u0000&lt;p&gt;The temperature and velocity equations are converted to a dimensionless form using suitable non-dimensional quantities, adhering to the imposed constraints. To solve these transformed dimensionless equations, the finite-difference method, based on the MAC (Marker and Cell) technique, is used. Comprehensive numerical simulations address various control parameters, including nanoparticle volume fraction, Rayleigh number, heat source or sink, Darcy number, Hartmann number and slit position. The results are illustrated through streamlines, isotherms, average Nusselt numbers and entropy generation plots, offering a clear visualization of the impact of these parameters across different scenarios.&lt;/p&gt;&lt;!--/ Abstract__block --&gt;\u0000&lt;h3&gt;Findings&lt;/h3&gt;\u0000&lt;p&gt;Results obtained show that the &lt;em&gt;Cu-Fe&lt;sub&gt;&lt;em&gt;3&lt;/em&gt;&lt;/sub&gt;O&lt;sub&gt;&lt;em&gt;4&lt;/em&gt; &lt;/sub&gt;&lt;/em&gt;hybrid nanofluid exhibits higher entropy generation than the &lt;em&gt;MoS&lt;sub&gt;&lt;em&gt;2&lt;/em&gt;&lt;/sub&gt;-Fe&lt;sub&gt;&lt;em&gt;&lt;em&gt;3&lt;/em&gt;&lt;/em&gt;&lt;/sub&gt;O&lt;sub&gt;&lt;em&gt;4&lt;/em&gt;&lt;/sub&gt;&lt;/em&gt; hybrid nanofluid when comparing them at a Rayleigh number of 10&lt;sup&gt;6&lt;/sup&gt; and a Darcy number of 10&lt;sup&gt;–1&lt;/sup&gt;. The &lt;em&gt;MoS&lt;sub&gt;&lt;em&gt;2&lt;/em&gt;&lt;/sub&gt;&lt;/em&gt; hybrid nanofluid demonstrates a low permeability, as evidenced by an average Darcy number of 10&lt;sup&gt;–3&lt;/sup&gt;, in comparison to the &lt;em&gt;Cu&lt;/em&gt; hybrid nanofluid. The isothermal contours for a Rayleigh number of 10&lt;sup&gt;4&lt;/sup&gt;are positioned parallel to the vertical walls. Additionally, the quantity of each isotherm contour adjacent to the hot wall is being monitored. The &lt;em&gt;Cu&lt;/em&gt; and &lt;em&gt;MoS&lt;sub&gt;&lt;em&gt;2&lt;/em&gt;&lt;/sub&gt;&lt;/em&gt; nanoparticles exhibit the highest average entropy generation at a Rayleigh number of 10&lt;sup&gt;5&lt;/sup&gt; and a Darcy number of 10&lt;sup&gt;–1&lt;/sup&gt;, respectively. When a uniform heat sink is present, the temperature gradient in the central part of the cavity decreases. In contrast, the absence of a heat source or sink leads to a more intense temperature distribution within the cavity. This differs significantly from the scenario where a uniform heat sink regulates the temperature.&lt;/p&gt;&lt;!--/ Abstract__block --&gt;\u0000&lt;h3&gt;Originality/value&lt;/h3&gt;\u0000&lt;p&gt;The originality of this study is to examine the generation of entropy in natural convection within a partially heated and cooled enclosure that contains hybrid nanofluids. Partially heated corners are essential for optimizing heat transfer in a wide range of industrial applications. This enhancement is achieved by increasing the surface area, which improves convective heat transfer. These d","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"209 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142448710","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":"Hemodynamic characteristics of pulsatile blood flow through bifurcated stenosed carotid artery","authors":"Swapnil Narayan Rajmane, Shaligram Tiwari","doi":"10.1108/hff-05-2024-0376","DOIUrl":"https://doi.org/10.1108/hff-05-2024-0376","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>Carotid artery is often associated with plaque deposition because of its shape and associated flow features. The shape of stenosed bifurcation is characterised by bifurcation angle (<em>ß</em>), planarity angle (<em>α</em>) and severity of stenosis (b). In the present work, three-dimensional numerical computations have been performed to analyse the effect of these geometrical parameters of carotid bifurcation on the characteristics of flow.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>Governing equations of this study were solved using ANSYS Fluent 20.1 and the blood flow was considered as laminar, pulsatile and non-Newtonian. Instantaneous flow behaviour has been illustrated using vorticity, velocity and helicity contours, whereas the time-averaged wall shear stress (<span>\u0000<mml:math display=\"inline\" xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mrow><mml:mover accent=\"true\"><mml:mrow><mml:msub><mml:mi>τ</mml:mi><mml:mi>w</mml:mi></mml:msub></mml:mrow><mml:mo stretchy=\"true\">¯</mml:mo></mml:mover></mml:mrow></mml:math></span>) and oscillatory shear index (OSI) quantify the time-averaged behaviour.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>The recirculation zone and secondary flow are ascertained to be stronger for higher bifurcation angle as compared to the lower bifurcation angle. Strength of the secondary flow is found to reduce with increase in <em>α</em> from 0° to 10°, whereas it grows as <em>α</em> varies from 10° to 20°. For higher bifurcation angles, <span>\u0000<mml:math display=\"inline\" xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mrow><mml:mover accent=\"true\"><mml:mrow><mml:msub><mml:mi>τ</mml:mi><mml:mi>w</mml:mi></mml:msub></mml:mrow><mml:mo stretchy=\"true\">¯</mml:mo></mml:mover></mml:mrow></mml:math></span> is lower than 2 Pa and OSI is greater than 0.2 on the outer walls. Similar observations were made for <span>\u0000<mml:math display=\"inline\" xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mrow><mml:mover accent=\"true\"><mml:mrow><mml:msub><mml:mi>τ</mml:mi><mml:mi>w</mml:mi></mml:msub></mml:mrow><mml:mo stretchy=\"true\">¯</mml:mo></mml:mover></mml:mrow></mml:math></span> and OSI distribution on bottom wall in non-planar cases, which predicted atherogenic locations.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>The values for ß were taken as 30°, 45°, 60° and 75°, whereas for <em>α</em>, range of 0°–20° was chosen. The stenosis was considered on the outer wall of internal carotid artery and its severity was considered within the range of 0%–60%.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"44 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142448938","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":"Computational multiphase mixture simulations of a two-phase R-744 ejector geometry in transcritical R-744 heat pump applications","authors":"Baris Burak Kanbur, Alexander Busch, Ekaterini E. Kriezi, Wiebke Brix Markussen, Martin Ryhl Kærn, Jóhannes Kristófersson, Jens Honore Walther","doi":"10.1108/hff-01-2024-0006","DOIUrl":"https://doi.org/10.1108/hff-01-2024-0006","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>Two-phase R-744 ejectors are critical components enabling energy recovery in R-744 heat pump and refrigeration systems, but despite their simple geometry, the flow physics involve complex multiphase mixing phenomena that need to be well-quantified for component and overall system improvement. This study aims to report on multiphase mixture simulations for a specific two-phase R-744 ejector with supercritical inlet conditions at the motive inlet side.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>Four different operating conditions, which have motive inlet pressure range of 90.1 bar–101.1 bar, are selected from an existing experimental data set. A two-phase thermodynamic equilibrium (TPTE) model is used, where the fluid properties are described by a thermodynamic look-up table.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>The results show that the TPTE model overpredicts mass flow rates at the motive inlet, resulting in a relative error ranging from 15.6% to 21.7%. For the mass flow rate at the suction inlet, the relative errors are found less than 1.5% for three cases, while the last case has an error of 12.4%. The maximum deviation of the mass entrainment ratio is found to be 8.0% between the TPTE model and the experimental data. Ejector efficiency ranges from 25.4% to 28.0%. A higher pressure difference between the ejector outlet and the diverging nozzle exit provides greater pressure lift.</p><!--/ Abstract__block -->\u0000<h3>Research limitations/implications</h3>\u0000<p>Based on the results, near future efforts will be to optimize estimation errors while enabling more detailed field analysis of pressure, density, temperature and enthalpy in the computational domain.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>The authors have two main original contributions: 1) the presented thermodynamic look-up table is unique and provides unique computation for the real-scale ejector domain. It was created by the authors and has not been applied before as far as we know. 2) To the best of the authors’ knowledge, this study is the first study that applies the STAR-CCM+ multiphase mixture model for R-744 mixture phenomena in heat pumps and refrigeration systems.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"124 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440017","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":"Experimental and numerical study of characteristic parameters of Taylor bubble in vertical pipe under short-time gas injection","authors":"Yufeng Ren, Changqing Bai, Hongyan Zhang","doi":"10.1108/hff-07-2024-0490","DOIUrl":"https://doi.org/10.1108/hff-07-2024-0490","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>This study aims to investigate the formation and characteristics of Taylor bubbles resulting from short-time gas injection in liquid-conveying pipelines. Understanding these characteristics is crucial for optimizing pipeline efficiency and enhancing production safety.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The authors conducted short-time gas injection experiments in a vertical rectangular pipe, focusing on Taylor bubble formation time and stable length. Computational fluid dynamics simulations using large eddy simulation and volume of fluid models were used to complement the experiments.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>Results reveal that the stable length of Taylor bubbles is significantly influenced by gas injection velocity and duration. Specifically, high injection velocity and duration lead to increased bubble aggregation and recirculation region capture, extending the stable length. Additionally, a higher injection velocity accelerates reaching the critical local gas volume fraction, thereby reducing formation time. The developed fitting formulas for stable length and formation time show good agreement with experimental data, with average errors of 6.5% and 7.39%, respectively. The predicted values of the formulas in glycerol-water and ethanol solutions are also in good agreement with the simulation results.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>This research provides new insights into Taylor bubble dynamics under short-time gas injection, offering predictive formulas for bubble formation time and stable length. These findings are valuable for optimizing industrial pipeline designs and mitigating potential safety issues.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"5 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440009","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":"Integrating forecasting methods to support finite element analysis and explore heat transfer complexities","authors":"Maryam Fatima, Peter S. Kim, Youming Lei, A.M. Siddiqui, Ayesha Sohail","doi":"10.1108/hff-06-2024-0477","DOIUrl":"https://doi.org/10.1108/hff-06-2024-0477","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>This paper aims to reduce the cost of experiments required to test the efficiency of materials suitable for artificial tissue ablation by increasing efficiency and accurately forecasting heating properties.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>A two-step numerical analysis is used to develop and simulate a bioheat model using improved finite element method and deep learning algorithms, systematically regulating temperature distributions within the hydrogel artificial tissue during radiofrequency ablation (RFA). The model connects supervised learning and finite element analysis data to optimize electrode configurations, ensuring precise heat application while protecting surrounding hydrogel integrity.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>The model accurately predicts a range of thermal changes critical for optimizing RFA, thereby enhancing treatment precision and minimizing impact on surrounding hydrogel materials. This computational approach not only advances the understanding of thermal dynamics but also provides a robust framework for improving therapeutic outcomes.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>A computational predictive bioheat model, incorporating deep learning to optimize electrode configurations and minimize collateral tissue damage, represents a pioneering approach in interventional research. This method offers efficient evaluation of thermal strategies with reduced computational overhead compared to traditional numerical methods.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"40 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440279","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":"Heat transfer in a non-uniformly heated enclosure filled by NEPCM water nanofluid","authors":"Rajesh Vemula, Hakan F. Öztop","doi":"10.1108/hff-06-2024-0465","DOIUrl":"https://doi.org/10.1108/hff-06-2024-0465","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>This paper aims to focuses on by investigate the heat transmission and free convective flow of a suspension of nano encapsulated phase change materials (NEPCMs) within an enclosure. Particles of NEPCM have a core-shell structure, with phase change material (PCM) serving as the core.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>The enclosure consists of a square chamber with an insulated wall on top and bottom and vertical walls that are differently heated. The governing equations are investigated using the finite element technique. A grid inspection and validation test are done to confirm the precision of the results.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>The effects of fusion temperature (varying from 0.1 to 0.9), Stefan number (changing from 0.2 to 0.7), Rayleigh number (varying from 10³ to 10⁶) and volume fraction of NEPCM nanoparticles (changing from 0 to 0.05) on the streamlines, isotherms, heat capacity ratio and average Nusselt number are investigated using graphs and tables. From this investigation, it is found that using a NEPCM nano suspension results in a significant enhancement in heat transfer compared to pure fluid. This augmentation becomes more important for the low Stefan number, which is around 16.57% approximately at 0.2. Secondary recirculation is formed near the upper left corner as a result of non-uniform heating of the left vertical border. This eddy expands notably as the Rayleigh number rises. The study findings indicate that the NEPCM nanosuspension has the potential to act as a smart working fluid, significantly enhancing average Nusselt numbers in enclosed chambers.</p><!--/ Abstract__block -->\u0000<h3>Research limitations/implications</h3>\u0000<p>The NEPCM particle consists of a core (n-octadecane, a phase-change material) and a shell (PMMA, an encapsulation material). The host fluid water and the NEPCM particles are considered to form a dilute suspension.</p><!--/ Abstract__block -->\u0000<h3>Practical implications</h3>\u0000<p>Using NEPCMs in energy storage thermal systems show potential for improving heat transfer efficiency in several engineering applications. NEPCMs merge the beneficial characteristics of PCMs with the enhanced thermal conductivity of nanoparticles, providing a flexible alternative for effective thermal energy storage and control.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>This paper aims to explore the free convective flow and heat transmission of NEPCM water-type nanofluid in a square chamber with an insulated top boundary, a uniformly heated bottom boundary, a cooled right boundary and a non-uniformly heated left boundary.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"75 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440280","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 double diffusive convective squeezing ternary nanofluid flow between parallel plates with activation energy and viscous dissipation","authors":"Sivasankaran Sivanandam, Chandrapushpam Thangaraj, M. Bhuvaneswari","doi":"10.1108/hff-05-2024-0365","DOIUrl":"https://doi.org/10.1108/hff-05-2024-0365","url":null,"abstract":"<h3>Purpose</h3>\u0000<p>This study aims to present the consequences of activation energy and the chemical reactions on the unsteady MHD squeezing flow of an incompressible ternary hybrid nanofluid (THN) comprising magnetite (FE₃O₄), multiwalled carbon nano-tubes (MWCNT) and copper (Cu) along with water (H2O) as the base fluid. This investigation is performed within the framework of two moving parallel plates under the influence of magnetic field and viscous dissipation.</p><!--/ Abstract__block -->\u0000<h3>Design/methodology/approach</h3>\u0000<p>Due to the complementary benefits of nanoparticles, THN is used to augment the heat transmit fluid’s efficacy. The flow situation is expressed as a system of dimensionless, nonlinear partial differential equations, which are reduced to a set of nonlinear ordinary differential equations (ODEs) by suitable similarity substitutions. These transformed ODEs are then solved through a semianalytical technique called differential transform method (DTM). The effects of several changing physical parameters on the flow, temperature, concentration and the substantial measures of interest have been deliberated through graphs. This study verifies the reliability of the results by performing a comparison analysis with prior researches.</p><!--/ Abstract__block -->\u0000<h3>Findings</h3>\u0000<p>The enhanced activation energy results in improved concentration distribution and declined Sherwood number. Enhancement in chemical reaction parameter causes disparities in concentration of the ternary nanofluid. When the Hartmann number is zero, value of skin friction is high, but Nusselt and Sherwood numbers values are small. Rising nanoparticles concentrations correspond to a boost in overall thermal conductivity, causing reduced temperature profile.</p><!--/ Abstract__block -->\u0000<h3>Research limitations/implications</h3>\u0000<p>Due to its firm and simple nature, its implications are in various fields like chemical industry and medical industry for designing practical problems into mathematical models and experimental analysis.</p><!--/ Abstract__block -->\u0000<h3>Practical implications</h3>\u0000<p>Deployment of the squeezed flow of ternary nanofluid with activation energy has significant consideration in nuclear reactors, vehicles, manufacturing facilities and engineering environments.</p><!--/ Abstract__block -->\u0000<h3>Social implications</h3>\u0000<p>This study would be contributing significantly in the field of medical technology for treating cancer through hyperthermia treatment, and in industrial processes like water desalination and purification.</p><!--/ Abstract__block -->\u0000<h3>Originality/value</h3>\u0000<p>In this problem, a semianalytical approach called DTM is adopted to explore the consequences of activation energy and chemical reactions on the squeezing flow of ternary nanofluid.</p><!--/ Abstract__block -->","PeriodicalId":14263,"journal":{"name":"International Journal of Numerical Methods for Heat & Fluid Flow","volume":"32 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440281","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}