Browsing by Author "Gürsoy, E."

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Experimental and numerical study on ferrohydrodynamic and magneto-convection of Fe3O4/water ferrofluid in a sudden expansion tube with dimpled fins
(Taiwan Institute of Chemical Engineers, 2024) Gürsoy, E.; Gürdal, M.; Gedik, E.; Arslan, K.; Dağdeviren, A.
Background: 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 thermo-hydraulic 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 φ=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 φ=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.
Investigation of magneto-convection characteristics in a sudden expanding channel with convex surface geometry under thermally developing flow conditions
(Emerald Publishing, 2024) Gürsoy, E.; Pazarlioğlu, H.K.; Gürdal, M.; Gedik, E.; Arslan, K.; Dağdeviren, A.
Purpose: The 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/approach: During 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. Findings: The 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/value: The 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.
Numerical simulation of sudden expansion tubes with Ag-MgO nanofluid and innovative fin structure: A thermo-fluidic analysis
(Elsevier B.V., 2024) Pazarlıoğlu, H.K.; Gürsoy, E.; Gürdal, M.; Said, Z.; Arslan, K.; Gedik, E.
This 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° to 90°) 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 3E-study (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° 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.
Numerical simulation of sudden expansion tubes with Ag-MgO nanofluid and innovative fin structure: A thermo-fluidic analysis
(2024.01.01) Pazarlioglu, H.K.; Gürsoy, E.; Gürdal, M.; Said, Z.; Arslan, K.; Gedik, E.
This 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.
Parametric analysis of different Al2O3 nanoparticle shapes and expansion angles for sudden expanded tube regarding the first law of thermodynamics
(Elsevier Masson s.r.l., 2024) Gürsoy, E.; Pazarlıoğlu, H.K.; Gürdal, M.; Gedik, E.; Arslan, K.
The thermo-hydraulic performance of Al2O3/H2O nanofluid with different nanoparticle shapes flowing in a sudden expansion tube with variable sudden expansion inclination angles and elliptical dimpled fins with different diameters were numerically investigated. Investigation of variable sudden expansion inclination angles, elliptic dimpled fins, and different nanoparticle shapes together reveals the novelty of this study. The main purpose of this study is to analyse the effect of nanofluid particle shapes, sudden expansion inclination angles, and elliptical dimpled fin on thermo-hydraulic performance for sudden expansion tube. The platelet, cylindrical, and blade nanoparticle shapes of Al2O3 nanoparticle (φ = 1.0 %) were separately mixed into base fluid to obtain working fluid. Numerical studies were carried out under laminar flow regime (500 ≤ Re ≤ 2000). Furthermore, the sudden expansion tube was assumed to have inclination angles with α = 30°, 45°, 60°, and 90°. The results presented that the highest Performance Evaluation Criterion is obtained for the case of DT6 using Al2O3/H2O with platelet nanoparticle shape at Re = 2000. Besides, the highest Nusselt number and Performance Evaluation Criterion were realized at the inclination angle of 45°. The increment rate of Nusselt number and Performance Evaluation Criterion at α = 45° were determined as 8.75 % and 10.52 % compared to α = 30°, respectively. Moreover, elliptical dimpled fins with sized as a = 6 mm and b = 12 mm presented the highest thermo-hydraulic performance, and this condition showed an increment of 153.9 % compared to case of a = 2 mm and b = 4 mm.
Parametric analysis of different Al2O3 nanoparticle shapes and expansion angles for sudden expanded tube regarding the first law of thermodynamics
(2024.01.01) Gürsoy, E.; Pazarlioglu, H.K.; Gürdal, M.; Gedik, E.; Arslan, K.
The thermo-hydraulic performance of Al2O3/H2O nanofluid with different nanoparticle shapes flowing in a sudden expansion tube with variable sudden expansion inclination angles and elliptical dimpled fins with different diameters were numerically investigated. Investigation of variable sudden expansion inclination angles, elliptic dimpled fins, and different nanoparticle shapes together reveals the novelty of this study. The main purpose of this study is to analyse the effect of nanofluid particle shapes, sudden expansion inclination angles, and elliptical dimpled fin on thermo-hydraulic performance for sudden expansion tube. The platelet, cylindrical, and blade nanoparticle shapes of Al2O3 nanoparticle (phi = 1.0 %) were separately mixed into base fluid to obtain working fluid. Numerical studies were carried out under laminar flow regime (500 <= Re <= 2000). Furthermore, the sudden expansion tube was assumed to have inclination angles with alpha = 30 degrees, 45 degrees, 60 degrees, and 90 degrees. The results presented that the highest Performance Evaluation Criterion is obtained for the case of DT6 using Al2O3/H2O with platelet nanoparticle shape at Re = 2000. Besides, the highest Nusselt number and Performance Evaluation Criterion were realized at the inclination angle of 45 degrees. The increment rate of Nusselt number and Performance Evaluation Criterion at alpha = 45 degrees were determined as 8.75 % and 10.52 % compared to alpha = 30 degrees, respectively. Moreover, elliptical dimpled fins with sized as a = 6 mm and b = 12 mm presented the highest thermo-hydraulic performance, and this condition showed an increment of 153.9 % compared to case of a = 2 mm and b = 4 mm.
Python-based machine learning estimation ofthermo-hydraulic performance along varying nanoparticle shape, nanofluid and tube configuration
(Elsevier Ltd, 2025) Gürsoy, E.; Tan, M.; Gürdal, M.; Çetinceviz, Y.
In this research article, a Python-based machine learning model prediction study was conducted based on the study results obtained from sudden expansion tubes containing different expansion angles, dimpled fin structures and nanofluids, whose thermo-hydraulic performance was previously examined. In the study, Artificial Neural Network and Ridge regression models were used to make predictions on the average Nusselt number (Nu), average Darcy friction factor (f) and performance evaluation criteria (PEC). Physical variations of the sudden expansion tube were taken into account and a detailed comparison of the results was made. A superior average Nu was acquired as 172.45 %, 22.05 %, 17.18 %, 13.65 %, and 7.76 % compared to Ag-MgO/H2O, Al2O3/H2O (blade), CoFe2O4/H2O, Al2O3/H2O (cylindrical), and Al2O3/H2O (platelet), respectively. The highest Performance Evaluation Criteria (PEC) for Re= 2000 based on Al2O3/H2O (platelet) shows an increase of 4.84 %, 12.08 %, 11.76 %, 66.05 %, and 148.94 % compared to Al2O3/H2O (cylindrical), Al2O3/H2O (blade), CoFe2O4/H2O, Fe3O4/H2O, and Ag-MgO/H2O, respectively. From the results obtained, it was determined that Python-based Machine Learning approach which facilitates custom optimizations showed a significant performance with small margins of error in predicting the heat transfer parameters. The lowest error rates of machine learning and polynomial ridge regression models ranged from 0.2 % to 5.4 % for the unseen test set and the application of Python-based algorithms provided considerable savings in calculation time compared to conventional methods. On the other hand, using machine learning models with feature engineering has been found to increase model performance by at least 30 %. In these years when studies on the predictions of thermo-hydraulic studies are very rare in the literature, this study is intended to facilitate scientists, engineers and academicians who will further study on this subject.
The first and second law analyses of thermodynamics for a human living at Kastamonu and Karabük cities in Türkiye
(Elsevier Ltd, 2024) Gürdal, M.; Gürsoy, E.; Gedik, E.
The phenomenon of heat dissipation and exergy transfer during the respiratory process in the human body holds significant importance concerning thermal comfort and wellness. In this study, the effect of the environmental condition of the Kastamonu and Karabük Provinces in the Türkiye's West Blacksea region on human body thermoregulation behavior has been investigated for the last eight years (2015–2022). It has been found that the cumulative heat loss and entropy generation associated with human respiration are markedly influenced by seasonal and environmental fluctuations. Besides, it has been detailly examined that the effects of average air temperature, average relative humidity, and average atmospheric pressure used as meteorological data on energy loss, entropy generation, and exergy flow have been investigated. The results reveal that most heat loss originates from metabolism energy at the rate of 5.935 W/m2. In addition, it was observed that heat exchange realized by passive systems such as convection and evaporation exhibited the maximum energy loss. Moreover, the results revealed that an increment in environmental temperature and relative humidity causes a decrement in convective heat loss. An evaluation of lowest heat loss and the highest exergy values was obtained specifically for İnebolu distriction (PZ-3). Accordingly, the minimum finding in heat loss, quantified as 1.9099 W/m2, was observed in the month of August, while the zenith in exergy, reaching 0.2846 W/m2, was likewise noted during the same temporal interval. Besides, the level of thermal comfort at each location is computed. According to the predicted mean vote (PMV) and Predicted Percentage Dissatisfied (PPD) indexes, it was concluded that the dissatisfaction of the atmospheric conditions in the provinces in four seasons is high on the human body.