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Öğe 3D numerical analysis of a Li-ion battery cooling system with honeycomb configuration in electrical vehicles(Elsevier Science Inc, 2024) Nazli, Celal; Gurdal, Mehmet; Arslan, KamilThis study focuses on the thermal challenges faced by lithium-ion batteries in electric vehicles and the importance of effective thermal management systems. It has been conducted a 3D numerical analysis to investigate the impact of different distances between batteries on heat transfer and flow characteristics in an air-cooled cooling module with an innovative honeycomb configuration. Boundary conditions and the study results were given with dimensionless parameters with longitudinal ratio (x/lambda), distance ratio (lambda), and height ratio (y/H). It was found that smaller distances between batteries let to higher temperatures at the beginning of the cooling channel due to the shorter channel width. However, as the distance between batteries increases, convective heat transfer performance improves, resulting in better temperature distributions and higher Nusselt numbers. The results shed light on the importance of optimizing the spatial arrangement of batteries in a cooling module to achieve efficient thermal management. This research contributes to bridging existing gaps in knowledge regarding battery thermal management in electric vehicles and provides insights for the design and development of more effective cooling strategies for lithium-ion batteries. In conclusion, according to the distance between batteries (S=1-3-5 mm) under a laminar flow regime, the best average Nussell numbers obtained for S=5 mm %17 and %7 heat enchantments compared to other S=1 mm and S=3mm cases, respectively. It can be observed that the convective heat transfer performance is optimal when all cases are located on the 9th battery. After the 9th battery column, the optimal heat transfer performance was observed for a thickness of 5 mm. The S=3 mm case exhibited a 7 % reduction in convective heat transfer performance compared to the S=5 mm case.Öğe Artificial intelligence approach for energy and entropy analyses of NiFe2O4/H2O nanofluid flow in a tube with vortex generator(Elsevier Sci Ltd, 2023) Gurdal, MehmetThe base purpose of the study is to examine the influence of vortex generator geometry and nanofluid on thermo-hydraulic and irreversibility behavior by using a numerical and predictable approach under a laminar flow regime. The selection of an original magnetic nanofluid, the handling of forced convection in a tube including a vortex generator with the artificial neural network approach, and the 2nd law analysis of thermodynamics reflect the novelty of the study. In this context, it was explored numerically for heat transfer and flow profiles of NiFe2O4/H2O flowing with 1% volume fraction in a tube with different vortex generator geometries. This study has been carried out with the solutions under constant heat flux conditions of 2000 W/m2 along the tube. The analyzes have been applied in the range of 500<2000. The Laminar model and single-phase approach in all analyses have been taken into account. Heat convection coefficient, pressure drop, and entropy generation were analyzed for the smooth tube and tube with wave ratio (WR=h/w) of 2, 3, and 4. Levenberg-Marquardt as train algorithm and Learngdm and Tansig as transfer function was used as the MLP network model in the present study. As a result, The highest heat transfer ratio, pressure drop, frictional entropy, and total entropy values are obtained for the tube with a wave ratio of 2. The highest deviation rates between the predicted and numerical results for WT1 and WT2 cases (the supreme among all cases) have been seen as 4.67% and 1.73% for the heat convection coefficient and pressure drop values, respectively.Öğe Effect of magnetic field locations on thermo-magnetic convection performance of Fe3O4/H2O ferrofluid flowing in a novel dimpled tube: An experimental study(Pergamon-Elsevier Science Ltd, 2023) Gursoy, Emrehan; Gurdal, Mehmet; Pazarlioglu, Hayati Kadir; Dagdeviren, Abdullah; Tekir, Mutlu; Arslan, Kamil; Gedik, EnginThe aim of this study is to examine the hydrothermal behavior of Fe3O4 Ferrofluid flowing under the effect of uniform magnetic field (0 T <= B <= 0.3 T). In addition, magnetic field locations were changed for each experiment to observe effect of the magnetic field locations (x/D = 20, 40, 60) on the hydrothermal behavior of the proposed system. Fe3O4 Ferrofluid was prepared in phi = 1.0% volume concentration in water and flows under the laminar regime (1131 <= Re <= 2102). Comparisons of the hydrothermal behavior of the novel proposed parameters were performed according to combinations of the different magnetic field locations and magnitudes. It is concluded that the highest Nusselt number was obtained using B = 0.3 T for the magnetic field location of x/D = 20 for both in smooth and dimpled tubes. Compared to B = 0 T, the Nusselt number enhancement was detected by 64.03% for smooth tube for the magnetic field location of x/D = 20 for B = 0.3 T whereas Nusselt number wasaugmented by 45.40% for dimpled tube for the same input parameters. Furthermore, no considerable changes in friction factor was determined under magnetic field effect when the application of magnetic field locations was changed. As a result of these findings, the highest increase in Performance Evaluation Criteria belonging dimpled tube was calculated by 33.54% at Re = 2102 for B = 0.16 T for the magnetic field location of x/D = 20. As a general conclusion, this study can shed light on investigating ferrofluids behavior under magnetic field applied in var-iable magnetic field locations.Öğe The effect of MHD flow on hydrothermal characteristics of ferro-nano-fluid in circular pipe(Taylor & Francis Inc, 2023) Taskesen, Edip; Tekir, Mutlu; Pazarlioglu, Hayati Kadir; Gurdal, Mehmet; Gedik, Engin; Arslan, KamilIn this study, the effect of the constant magnetic field (MF) on the convective heat transfer characteristics of Fe3O4/H2O ferro-nano-fluid with different nano-fluid volumetric concentrations (1.0%, 2.0%, and 5.0%) flowing in a circular pipe has been studied experimentally. Experiments have been conducted under laminar flow regime (1000 <= Re <= 2300). Based on the experimental data, a good agreement has been found with the results and the well-known correlations in the literature. Also, it was obtained that increasing flow rate let to increase in Nusselt number. One of the most important results obtained is that the presence of MF offers up to 8.32% convective heat transfer enhancement compared with the absence of a MF. In addition, the constant MF applied externally to the flow is a key factor to control the convective heat transfer for such kind of geometry, which is widely used in thermal engineering systems.Öğe EFFECT OF NANOPARTICLE SHAPE ON NANOFLUID FLOW IN CONICAL HELICAL TUBE(Begell House, Inc, 2022) Altunay, Fethi M.; Ali, Majdi A. M.; Gurdal, Mehmet; Pazarlioglu, Hayati Kadir; Arslan, Kamil; Gedik, EnginThe nanofluid flow in a conical helical tube was numerically investigated. The study has been carried out in three-dimensional laminar flow (85.73 <= De <= 175.55) condition. Al2O3-water nanofluid with different nanoparticle volume fractions (1.0%, 2.0%, 3.0%) has been used as the working fluid in the numerical analyzes. In addition, studies were carried out for blade, platelet, and cylindrical nanoparticle shapes. The average Nusselt numbers and the average Darcy friction factors have been used to estimate the flow and heat transfer performance of nanofluid flow in the conical helical tubes. Numerical results of the study have been presented as the variation of average Nusselt number and average Darcy friction factor with Dean number, nanoparticle shape, and nanoparticle volume fraction. As a result, the highest convective heat transfer performance has been obtained for the cylindrical nanoparticle shape of the %3.0 Al2O3-water nanofluid.Öğe EFFECTS OF SINUSOIDAL STRIP ELEMENT WITH DIFFERENT AMPLITUDES ON HEAT TRANSFER AND FLOW CHARACTERISTICS OF CIRCULAR CHANNELS(Begell House Inc, 2019) Altun, Aziz Hakan; Gurdal, Mehmet; Berber, AdnanIn this study, the effect of Reynolds number in turbulent flow on heat transfer and flow characteristics for different sinusoidal decoupled strip elements placed separately from the pipe was investigated experimentally. Experiments were carried out under forced convection and constant heat flux conditions. Corrugated strip elements were positioned axially at the pipe center, which draws a sinusoid used as a turbulator. Experiments were repeated for three different amplitudes of sinusoidal strip elements with 3D/4 width, D/8, 3D/16, and D/4. Experiments showed that although the strip elements enhanced heat transfer at different rates, they also caused a considerable pressure drop. As a result, it was seen that the heat transfer ratio, i.e., the Nusselt number, increased with the amplitude value. This ratio is 47% to 80% at the D/8 amplitude, 44% to 100% at the 3D/16 amplitude, and 75% to 174% at the D/4 amplitude in a straight pipe. It was determined that the friction coefficient is significantly affected by a sinusoidal corrugated strip element. It was determined that the value of friction coefficient is around 0.02 in a smooth pipe, 0.17 to 0.25 at n = D/8, 0.35 to 0.42 at n = 3D/16, and 0.43 to 0.45 at n = D/4.Öğe Effects of using nanofluid, applying a magnetic field, and placing turbulators in channels on the convective heat transfer: A comprehensive review(Pergamon-Elsevier Science Ltd, 2022) Gurdal, Mehmet; Arslan, Kamil; Gedik, Engin; Minea, Alina AdrianaRecent studies in the field of thermal engineering revealed that employing nanofluid as a working fluid in a specific channel, considering both turbulators and magnetic field effect is scarce. Studies on the convective heat transfer performance of the thermal systems focus mostly on the effect of using either nanofluid as a new fluid, magnetic field, or turbulators. This review highlights the single and combined effects of these parameters on the heat transfer enhancement of such systems. Nanofluid type, its volume fraction, channel and turbulator geometry, magnetic field type, and flow regime were considered as the base parameters while the enhancement in heat transfer is evaluated. From a state-of-the-art review, it was noticed that most studies reveal that increasing the volume fraction of nanofluid, magnetic field strength, and Reynolds number can attain an upsurge in the heat transfer in a specific channel. Nevertheless, drawbacks are poorly discussed in the open literature. Regarding the turbulator geometry, which actually limits the magnetohydrodynamic and thermal boundary layer development, its complexity boosts also the convective heat transfer. The maximum heat transfer enhancement was noticed for higher nanoparticle volume fractions, higher magnetic field strengths, and complex geometries in channel flow. The highest heat transfer improvement was obtained for the MWCNT/H2O nanofluid (i.e., between 70% and 190%). With the effect of magnetic field intensity of Ha = 30 applied to the Cu/H2O nanofluid flow, a thermal recovery of 76% was achieved. Concluding, this comprehensive review can be beneficial to researchers working in the field of flow and heat transfer applications with the use of nanofluid, turbulator, and magnetic field together.Öğe Experimental and numerical study on ferrohydrodynamic and magneto-convection of Fe3O4/water ferrofluid in a sudden expansion tube with dimpled fins(Elsevier, 2024) Guersoy, Emrehan; Gurdal, Mehmet; Gedik, Engin; Arslan, Kamil; Dagdeviren, AbdullahBackground: This study experimentally and numerically addresses magnetohydrodynamic forced convection including dimpled fins, Fe3O4/water ferrofluid, and DC magnetic field. In this research, focusing on the thermohydraulic performance improvement of a sudden expansion tube. It has been used different inlet diameters, dimple sizes, ferro nanoparticle concentrations, and magnetic field strengths to examine the heat transfer and fluid dynamics characteristics of the system. Methods: The study consists of two parts, i) experimental and ii) numerical. Steady-state, incompressible, Newtonian flow were considered but chemical reaction, viscous dissipation, buoyancy, and radiative heat transfer were neglected in this study. On the other hand, numerical solutions were carried out for single-phase method. This study was first compared with the studies in the literature on the flow in a sudden expansion tube without dimpled fins and the error rate was found to be less than 10%. In the analysis, dimpled fins with d=3, 5, and 7 mm at each P=15 mm (P/d=5.0, 3.0, and 2.14) have been used. As working fluid, Fe3O4/water ferrofluid with volume concentration of phi=1.0 % and 2.0% have been analyzed. Additionally, DC magnetic fields, which strength of Ha=0.1, 0.3, 0.5, 1.1, 3.2, and 5.3 (B =0.01, 0.03, 0.05, 0.1, 0.3, and 0.5T), have been applied on the sudden expansion tube surface as external force. Significant findings: Dimpled fins enhance the heat transfer by disrupting the boundary layer and forming secondary flows, while the ferrofluid increases the thermal conductivity and viscosity of the base fluid. Based on these explanations, dimpled fins increased the convective heat transfer rate at the rate of 96.0% compared with smooth tube. In addition, Fe3O4/water ferrofluid with phi=2.0 % performed the highest performance and performance evaluation criteria increased by 8.5%. The magnetic field also contributes to the heat transfer enhancement by inducing Lorentz force and mixing the flow. Excessive increasing of magnetic field strength adversely affected the system performance, and the highest performance evaluation criterion is acquired at Ha=3.2 by increasing 3.9%. Compared with smooth tube, compound effect of dimpled fins, Fe3O4/water ferrofluid, and magnetic field improved the average Nusselt number and performance evaluation criterion at the rate of 279.8 % and 207.9%, respectively.Öğe Experimental investigation on thermo hydraulic performance of ferronanofluid flow in a dimpled tube under magnetic field effect(Taylor & Francis Inc, 2023) Gurdal, Mehmet; Pazarlioglu, Hayati Kadir; Tekir, Mutlu; Arslan, Kamil; Gedik, Engin; Taskesen, EdipActive and passive techniques have been utilized together to enhance heat transfer in this study. The ferronanofluid, magnetic field, and dimpled tube have not been utilized together in the literature so far. Regarding this issue, this investigation is the first experimental study to specify the effect of use of these three effects simultaneously. The concept of this study is to determine the thermo-hydraulic performance of Fe3O4/H2O flow inside a dimpled tube under magnetic field effect. Constant and uniform heat flux of 4500 W/m(2) has been applied on the surface of the tube. The work aims to gain data in the range of laminar flow (1131 <= Re <= 2102) in the dimpled tube. Dimple geometry with pitch ratio of P/d = 3.75, magnetic field (B = 0.03 <= T <= 0.16), and nanoparticle volume fraction of 1.0% are the base variables. The results showed that Nusselt number increases with increasing Reynolds number and magnetic field intensity. The highest increase in Nusselt number is obtained as 115.31% compared with the distilled water flow in the smooth tube for the case of magnetic field intensity of 0.3 T. The highest Performance Evaluation Criteria value is also determined as 1.44 for the case of ferronanofluid flow in dimpled tube at Re = 1131 in absence of magnetic field.Öğe The first and second law analyses of thermodynamics for CoFe2O4/H2O flow in a sudden expansion tube inserted elliptical dimpled fins(Pergamon-Elsevier Science Ltd, 2023) Pazarlioglu, Hayati Kadir; Gursoy, Emrehan; Gurdal, Mehmet; Tekir, Mutlu; Gedik, Engin; Arslan, Kamil; Taskesen, EdipIn this paper, thermo-hydraulic performance and entropy generation of the sudden expansion tube with elliptical dimpled fins (DFs) at different directions was computationally performed at different Reynolds (Re) numbers ranging between 100 & LE;Re & LE;2000 using cobalt ferrite/H2O (CoFe2O4/H2O) nanofluid (NF) (0.0 & LE;& phi;& LE; 2.0). The novelty of this study is to investigate the effect of the elliptical DF and its arrays in the sudden expansion tube in terms of thermodynamics laws (energy and entropy generations). While the sudden expansion ratio (D2/D1) is 2.5, elliptical dimple width (a) and height (b) show variations between 4 and 8 mm. In addition, the distances among elliptical DFs (P) are taken as P = 10, 15, and 20 mm while the diameter (D1) and length (L1) of the inlet tube are D1=8 mm and L1=375 mm. The diameter (D2) and length (L2) of the tube with the sudden expanding and elliptical DFs are D2=20 mm and L2=1125 mm, respectively. The study comprehensively exhibits results of the thermo-hydraulic performance and entropy generation based on numerical data. The results demonstrated that the highest heat transfer rate is recorded by the case of DT3, and DT3 enhances the convective heat transfer rate by 221%, and increases the pressure drop by 17.38% at Re=2000 compared to smooth tube (ST). It was observed that as the Re increases, the performance evaluation criteria (PEC) gradually increases too, and the highest PEC has been obtained for DT3 as 2.11 at Re=2000. The entropy generation (EnG) was also evaluated in terms of both geometric designs and volumetric concentrations. Moreover, the best total EnG was found around 17% for DT3 at the Re=1000 and & phi;=2.0% compared to ST using H2O. Consequence of the applied analyses, the use of elliptic DFs in a sudden expansion tube enhances the convective heat transfer rate and decreases total EnG.Öğe IMPACT OF TWISTED DUCTS WITH DIFFERENT TWIST RATIOS ON HEAT TRANSFER AND FLUID CHARACTERISTICS OF NiO/WATER NANOFLUID FLOW UNDER MAGNETIC FIELD EFFECT(Begell House Inc, 2022) Pazarlioglu, Hayati Kadir; Gurdal, Mehmet; Tekir, Mutlu; Arslan, Kamil; Gedik, EnginLaminar forced convection of NiO/water nanofluid in a twisted square duct has been investigated numerically under the effect of an external magnetic field (B = 0 G, 450 G, and 550 G) in the Reynolds number range of 500 <= Re <= 2000. Four different twist ratios (D/L = 0.0, 1.0, 1.5, and 2.0) of the square duct have also been examined. The nanoparticle volume fractions (NPVF) of NiO/water nanofluid have been selected between 0.6 vol.% and 2.5 vol.%. The effects of the magnitude of the magnetic field (MF), twist ratio, Reynolds number, and nanoparticle volume fraction on thermohydraulic performance have been examined by using the homogeneous model in the numerical analyses. The results of the numerical computations have been reported with average Nusselt number Nu, pressure loss, average Darcy friction factor f, and performance evaluation criterion (PEC). The highest heat transfer increment by 20% has been achieved at D/L = 2.0 with the highest nanoparticle volume fraction, namely, 2.5 vol.% NiO/water nanofluid, compared to the case of distilled water (DW) flowing in a plain duct (PD). In addition, it was determined that the magnetic field effect increases the convective heat transfer in the twisted duct with D/L = 2.0 up to 35% compared to the cases in the absence of a magnetic field at D/L = 2.0. Among all cases, the highest PEC has been obtained with 2.5 vol.% NiO/water nanofluid flowing in the twisted duct with the twist ratio D/L = 2.0.Öğe Implementation of hybrid nanofluid flowing in dimpled tube subjected to magnetic field(Pergamon-Elsevier Science Ltd, 2022) Gurdal, Mehmet; Pazarlioglu, Hayati Kadir; Tekir, Mutlu; Altunay, Fethi Murat; Arslan, Kamil; Gedik, EnginTo pursue of enhancement convective heat transfer, both active and passive techniques have been elucidated simultaneously in this study. The effect of hybrid nanofluid flow in a dimpled tube implemented constant magnetic field (0 T <= B <= 0.3 T) to determine the convective heat transfer rate has not been investigated comparatively either numerically or experimentally, so far. Therefore, this study is the first study to elucidate the effect of hybrid nanofluid flow under the effect of a magnetic field at the fully developed hydrodynamic and developing thermally flow condition. Hydrothermal behavior of 1.0% vol. Fe3O4/H2O, 1.0% vol. Cu/H2O as mono nanofluid and 0.5% vol. Fe3O4-0.5% vol. Cu/H2O as hybrid nanofluid flow in the dimpled tube has been examined under constant heat flux boundary condition (q = 4357 W/m2) and laminar flow regime (1131 <= Re <= 2102). As a result of experiments and numerical analyses, it is concluded that Nusselt number and friction factor have been enhanced using the magnetic field. Hybrid nanofluid flow in the dimpled tube implemented the magnetic field with the magnitude of 0.3 T causes to increase the Nusselt number and friction factor up to 11.87% and 6.19% for numerical, 174.65%, and 169.4% for experimental compared to the case of absence of a magnetic field, respectively.Öğe An innovative approach of alternating magnetic field diversified with different wave types and magnet positions for ferrofluid flow in dimpled tube(Elsevier, 2023) Gurdal, Mehmet; Gursoy, Emrehan; Pazarlioglu, Hayati Kadir; Arslan, Kamil; Gedik, EnginThe purpose of the present experimental study is to investigate the forced magneto-convection of the Fe3O4/H2O ferrofluid flowing along smooth and dimpled tubes implemented with alternating magnetic field (B = 0.16 T and f = 5 Hz). All experiments were carried out for the working fluids pure water and ferrofluid with 1.0% volume fraction in the laminar flow regime (1131 & LE; Re & LE; 2102). Also, an original perspective of this study is to use of changing magnetic field wave types (Sinus, Triangle, and Square) and positions at different axial distances (x/D = 20, x/D = 40, and x/D = 60). Findings shed light on that the highest convective heat transfer ratio was realized at x/D = 20 location and square wave type for all cases. The average Nusselt number of the dimpled tube subjected to square wave type applied at x/D = 20 is increased by 58.13% compared to smooth tube without magnetic field and using H2O as working fluid. Moreover, when the friction factor was compared for the same conditions, the increment rate has been seen by 85.73%. Although Nusselt number is reached to its highest level using square wave type, the highest Performance Evaluation Criteria is detected around 1.45 using dimpled tube subjected to alternating magnetic field with triangle wave type applied at x/D = 20 for Re = 1131.Öğe INVESTIGATION OF EFFECTS ON HEAT TRANSFER AND FLOW CHARACTERISTICS OF Cr-Ni ALLOY AND ALUMINUM PINS PLACED IN AISI 304 TUBE(Vinca Inst Nuclear Sci, 2020) Berber, Adnan; Bagirsakci, Kazim; Gurdal, MehmetIn this study, the effects of cylindrical aluminum and Cr-Ni alloy pins placed in different arrangements on the inner wall of the pipe in the turbulent flow, the effects of heat transfer and flow characteristics on different Reynolds numbers have been experimentally investigated. The experiments were carried out under forced flow and constant heat flow conditions. Air is preferred as the fluid and the fluid velocity is adjusted between Reynolds number of 10000 and 50000. It has been observed that the Nusselt values obtained over the number of Reynolds number for the 5 different test tubes are arranged in a line from large to small, sequential row aluminum pin, sequential row Cr-Ni alloy pin, diagonal row aluminum pin, diagonal row Cr-Ni alloy pin, plain tube. There are also CFD analysis for each material, arrangements and pins geometry sets. On the other hand, it was determined that friction coefficient is directly proportional to the increase of heat transfer coefficient. As a result, it is observed that experimental results are compatible with both literature and numerical study.Öğe Investigation of magneto-convection characteristics in a sudden expanding channel with convex surface geometry under thermally developing flow conditions(Emerald Group Publishing Ltd, 2024) Gursoy, Emrehan; Pazarlioglu, Hayati Kadir; Gurdal, Mehmet; Gedik, Engin; Arslan, Kamil; Dagdeviren, AbdullahPurposeThe purpose of this study is to analyse the magnetic field effect on Fe3O4/H2O Ferrofluid flowing in a sudden expansion tube, which has specific behaviour in terms of rheology, with convex dimple fins. Because the investigation of flow separation is a prominent application in performance, the effect of magnetic field and convex dimple on the thermo-hydraulic performance of sudden expansion tube are examined, in detail.Design/methodology/approachDuring the solution of the boundary conditions of the sudden expansion tube, finite volume method was used. Analyses have been conducted considering the single-phase solution, steady-state, incompressible fluid and no-slip condition of the wall under forced convection conditions. In the analyses, it has been assumed that the flow was developing thermally and has been fully developed hydrodynamically.FindingsThe present study focuses on exploring the influence of the magnetic field, nanofluid concentration and convex dimple fins on the thermo-hydraulic performance of sudden expansion tube. The results indicate that the strength of the magnetic field, nanofluid concentration and convex dimple fins have a positive effect on the convective heat transfer in the system.Originality/valueThe authors conducted numerical studies, determining through a literature search that no one had yet investigated enhancing heat transfer on a sudden expansion tube using combinations of magnetic fields, nanofluids and convex dimple fins. The results of the numerical analyses provide valuable information about the improvement of heat transfer and system performance in electronic device cooling and heat exchangers.Öğe Numerical investigation on turbulent flow and heat transfer characteristics of ferro-nanofluid flowing in dimpled tube under magnetic field effect(Pergamon-Elsevier Science Ltd, 2022) Gurdal, Mehmet; Pazarlioglu, Hayati Kadir; Tekir, Mutlu; Arslan, Kamil; Gedik, EnginFor the aim of increasing the heat transfer enhancement, a hybrid method in which active and passive heat recovery techniques have been used together. The usage of nanofluid, MHD and dimpled fins tube have not been utilized together so far. Regarding this issue, this study is the first numerical study to determine effect of usage of three effects together comprehensively. In this study, thermo-hydraulic performance of Fe3O4/H2O nanofluid (ferro-nanofluid) flow inside dimpled tube under magnetic field effect has been examined numerically. The main purpose of the study is to obtain numerical data for turbulent flow in the spherical dimpled tubes providing some aid to design a highly efficient thermal energy storage devices. Dimple geometry with nondimensional pitch ratio (P/d = 3.75, 7.50 and 11.25), Hartmann number (Ha = 75, 150, 225) and nanoparticle volume fraction (phi = 0.5, 1.0 and 2.5 vol%) are the parameters investigated in this study. The numerical analyses have been carried out Reynolds number ranging from 10,000 to 50,000 at a constant heat flux at 20 kW/m2. The simulations have been built up by Realizable k-epsilon turbulence model and single-phase approach. Also, MagnetoHydroDynamic (MHD) module has also been activated for defining magnetic field effect. The results showed that Nusselt number increases with increasing Reynolds number and decreasing pitch ratio. The dimple geometry type of P/d = 7.50 has been determined as the most efficient dimple geometry type. In the case of highest magnetic field intensity, the highest Nusselt number increment (72.48%) has been obtained for phi = 2.5 vol% compared to the base fluid of distilled water using as the working fluid for smooth tube. The highest PEC value was also obtained as 1.126 for the case of P/d = 7.5, phi = 2.5 vol% and Ha = 75. In addition, the effect of magnetic field intensity on velocity and temperature distributions has been presented with contour graphs.Öğe Numerical simulation of sudden expansion tubes with Ag-MgO nanofluid and innovative fin structure: A thermo-fluidic analysis(Elsevier Science Inc, 2024) Pazarlioglu, Hayati Kadir; Gursoy, Emrehan; Gurdal, Mehmet; Said, Zafar; Arslan, Kamil; Gedik, EnginThis study introduces an innovative approach to employing mono/hybrid nanofluids in tubes with sudden expansion, structured at various expansion angles and equipped with novel capsule -type dimpled fins. Pumping of hybrid nanofluids into sudden expansion tube combined with capsule -type dimpled fins and different expansion angles (ranging from 30 degrees to 90 degrees ) has not been investigated so far in terms of energy, exergy, and entropy analyses. Recognizing the attention currently devoted to the climate effect of a system exposed to high thermal loads, this study sheds light on the literature how a system preferred by engineers and professionals can be cooled down efficiently to increase the performance of the system. The objective is to analyze a detailed 3Estudy (energy, exergy, and entropy production) on water -based mono and hybrid nanofluids, exploring various volume fractions and combinations (including 2.0 % Ag, 2.0 % MgO, and blends of Ag-MgO). The study finds that a 45 degrees expansion angle, combined with capsule -type dimpled fins and 0.5 % Ag-1.5 % MgO nanofluid, offers the most efficient tube design, enhancing the average Nusselt number by 20.0 % . This configuration, also, reduces total entropy generation by approximately 23.0 % and shows exergy output by 26.0 % , though it does lead to a 26.0 % decrease in second law efficiency due to increased pumping power. Interestingly, the first law efficiency remains unchanged mainly across different nanofluid types. These findings provide valuable insights into optimizing heat transfer and fluid dynamics in engineering applications.
