TY - JOUR A1 - Biswas, Nirmalendu A1 - Mandal, Dipak Kumar A1 - Manna, Nirmal K. A1 - Benim, Ali Cemal T1 - Thermomagnetic convection and entropy generation in a hybrid nanofluid filled wavy-walled cavity heated non-uniformly JF - Archives of Thermodynamics N2 - In this work, thermomagnetic convection and irreversibility production in a hybrid nanofluid-filled wavy-walled porous thermal system containing a semi-circular heated bottom is presented. Both the sidewalls of the enclosure are cooled and undulated with varying undulation numbers. The lower wall is partially undulated following a semi-circular-shaped object and is heated isothermally. The horizontal walls are insulated. The cavity is occupied with Cu-Al2O3/water-based hybrid nanofluid and porous substances under the impact of the evenly applied horizontal magnetic field. This work significantly contributes to the existing research rendering an exhaustive understanding of the hydrothermal flow-physics as well as irreversibility production of a hybrid nanofluid in the cavity having surface undulation. The Galerkin weighted finite element method is utilized to solve the mathematical model. The hydrothermal performance of the thermal system is considerably influenced by various pertinent factors such as Darcy-Rayleigh number, Darcy number, Hartmann number, and number of undulations. The wall undulations have a critical role in altering the hydrothermal performance. Heatlines are used to analyse heat transport dynamics from the protruded hot surface to the heat sink. The protruded heater wall induces the formation of a hot upward plume in the nearest fluid layers. The flow divides into two parts forming a pair of circulations due to symmetrical cooling at the sidewalls. The flow behaviours are significantly dampened by increasing the Hartmann number. The associated total entropy generation is also demonstrated. This study contributes to the existing domain knowledge and provides insights for designing and optimizing similar thermal systems. KW - Wärmeübertragung KW - Numerische Strömungssimulation KW - Finite-Elemente-Methode KW - Nanofluidik Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-52344 SN - 1231-0956 SP - 61 EP - 81 PB - Polish Academy of Sciences ER - TY - CHAP A1 - Özman, Cansu A1 - Gül, Fethi A1 - Diederich, Michael A1 - Benim, Ali Cemal A1 - Janoske, Uwe T1 - Computational and Experimental Investigation of Flow and Convective Heat Transfer along Rough Surfaces T2 - Proceedings of CONV-22: Int. Symp. on Convective Heat and Mass Transfer June 5 – 10, 2022, Turkey KW - Numerische Strömungssimulation KW - Wärmeübertragung KW - Rauigkeit KW - Turbulenzmodell Y1 - 2022 U6 - https://doi.org/10.1615/ICHMT.2022.CONV22.590 SP - 447 EP - 454 PB - Begellhouse ER - TY - CHAP A1 - Benim, Ali Cemal A1 - Çiçek, Aydın T1 - Investigation of the Thermohydraulics of an EGS Project in Turkey: Comparative Assessment of Water and CO2 as Heat Transfer Fluid T2 - Proceedings of CONV-22: Int. Symp. on Convective Heat and Mass Transfer June 5 – 10, 2022, Turkey KW - Numerische Strömungssimulation KW - Thermohydraulik KW - Geothermik KW - Wärmeübertragung Y1 - 2022 U6 - https://doi.org/10.1615/ICHMT.2022.CONV22.580 SP - 439 EP - 446 PB - Begellhouse ER - TY - CHAP A1 - Yalçınkaya, Orhan A1 - Durmaz, Ufuk A1 - Tepe, Ahmet Ümit A1 - Benim, Ali Cemal A1 - Uysal, Ünal T1 - Numerical Analysis of Roughened Target Surface for Enhancing Jet Impingement Cooling T2 - Advances in Computational Heat and Mass Transfer: Proceedings of the 14th International Conference on Computational Heat and Mass Transfer (ICCHMT 2023), 4-8 September, 2023, Düsseldorf, Germany KW - Numerische Strömungssimulation KW - Wärmeübertragung KW - Aufrauhen KW - Kühlung KW - Jet Impingement Cooling Y1 - 2024 SN - 9783031672408 U6 - https://doi.org/10.1007/978-3-031-67241-5_64 SN - 2195-4356 VL - 1 SP - 713 EP - 720 PB - Springer Nature CY - Cham ER - TY - CHAP A1 - Bhattacharyya, Suvanjan A1 - Jain, Naman A1 - Bhatt, Tapasvi A1 - Ghosh, Soumya A1 - Benim, Ali Cemal T1 - Heat Transfer Augmentation in a Mini-channel Using Magnetic Nanofluid and Magnetic Vortex T2 - Advances in Computational Heat and Mass Transfer: Proceedings of the 14th International Conference on Computational Heat and Mass Transfer (ICCHMT 2023), 4-8 September, 2023, Düsseldorf, Germany KW - Wärmeübertragung KW - Numerische Strömungssimulation KW - Laminare Strömung KW - Magnetische Flüssigkeit KW - Magnetischer Flussschlauch Y1 - 2024 SN - 9783031666087 U6 - https://doi.org/10.1007/978-3-031-66609-4_1 SN - 2195-4356 VL - 2 SP - 3 EP - 11 PB - Springer Nature CY - Cham ER - TY - CHAP A1 - Vishwakarma, Devendra Kumar A1 - Bhattacharyya, Suvanjan A1 - Soni, Manoj Kumar A1 - Ghosh, Soumya A1 - Benim, Ali Cemal ED - Benim, Ali Cemal ED - Bennacer, Rachid ED - Mohamad, Abdulmajeed A. ED - Ocłoń, Paweł ED - Suh, Sang-Ho ED - Taler, Jan T1 - Transition Flow Heat Transfer and Pressure Drop in a Uniformly Heated Inclined Solar Air Heater Fitted with Wavy Tapes T2 - Advances in Computational Heat and Mass Transfer: Proceedings of the 14th International Conference on Computational Heat and Mass Transfer (ICCHMT 2023), 4-8 September, 2023, Düsseldorf, Germany KW - Numerische Strömungssimulation KW - Druckabfall KW - Wärmeübertragung Y1 - 2024 SN - 9783031672408 U6 - https://doi.org/10.1007/978-3-031-67241-5_63 SN - 2195-4356 VL - 1 SP - 703 EP - 712 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Sidharth, K. Pillai A1 - Rajkumar, Mattacaud R. A1 - Chithrakumar, V. K. A1 - Asirvatham, Godson L. A1 - Benim, Ali Cemal A1 - Wogwises, Somchai T1 - Impact of increased outer wall rotation on convection in a vertical annulus with a stationary heated inner cylinder JF - Heat Transfer N2 - The interplay of centrifugal and buoyant forces on convective heat transfer in a vertical annulus formed by rotating adiabatic outer cylinder and stationary heated inner cylinder has been experimentally and numerically investigated. Experiments were performed for rotational speeds corresponding to the rotation parameter ζ in the range of 527 ≤ ζ ≤ 2860, maintaining the heat flux of the heated stationary inner cylinder as 80 W/m2, for radius ratio (η) and aspect ratio of the vertical annulus being 0.614 and 0.052, respectively. The problem was investigated numerically using the commercial computational fluid dynamics package, ANSYS CFX. The numerical methodology has been validated by comparing the numerically predicted average surface Nusselt number with experimentally obtained values. The comparison revealed an enhancement of the thermal performance of the heated stationary inner cylinder in the range 527 ≤ ζ ≤ 1190 due to the increase in turbulence intensity towards the heated inner cylinder. However, when the rotation parameter was increased further in the range 1190 ≤ ζ ≤ 2860, the thermal performance of the stationary heated inner cylinder showed only marginal improvement. The aforementioned thermal behavior of the inner heated stationary cylinder has been explored based on the flow statistics gathered from the numerical simulations. KW - Numerische Strömungssimulation KW - Nusselt-Zahl KW - Statischer Auftrieb KW - Zentrifugalkraft KW - Zylinder (Maschinenbau) KW - Wärmeübertragung Y1 - 2022 U6 - https://doi.org/10.1002/htj.22617 SN - 2688-4534 VL - 51 IS - 7 SP - 6656 EP - 6684 PB - Wiley ER - TY - JOUR A1 - Benim, Ali Cemal A1 - Cagan, Markos A1 - Günes, Dogan T1 - Computational analysis of transient heat transfer in turbulent pipe flow JF - International Journal of Thermal Sciences KW - Turbulenzmodell KW - Wärmeübertragung KW - Numerische Strömungssimulation KW - Turbulente Strömung Y1 - 2004 U6 - https://doi.org/https://doi.org/10.1016/j.ijthermalsci.2004.02.012 SN - 1290-0729 VL - 43 IS - 8 SP - 725 EP - 732 PB - Elsevier ER - TY - JOUR A1 - Benim, Ali Cemal T1 - A finite element solution of radiative heat transfer in participating media utilizing the moment method JF - Computer Methods in Applied Mechanics and Engineering KW - Finite-Elemente-Methode KW - Wärmeübertragung KW - Wärmestrahlung KW - Momentenmethode KW - Numerische Strömungssimulation Y1 - 1988 U6 - https://doi.org/10.1016/0045-7825(88)90065-5 SN - 0045-7825 VL - 67 IS - 1 SP - 1 EP - 14 PB - Elsevier ER - TY - JOUR A1 - Yalçınkaya, Orhan A1 - Durmaz, Ufuk A1 - Tepe, Ahmet Ümit A1 - Benim, Ali Cemal A1 - Uysal, Ünal T1 - Heat and Flow Characteristics of Aerofoil-Shaped Fins on a Curved Target Surface in a Confined Channel for an Impinging Jet Array JF - Energies N2 - The main purpose of this investigation was to explore the heat transfer and flow characteristics of aero-foil-shaped fins combined with extended jet holes, specifically focusing on their feasibility in cooling turbine blades. In this study, a comprehensive investigation was carried out by applying impinging jet array cooling (IJAC) on a semi-circular curved surface, which was roughened using aerofoil-shaped fins. Numerical computations were conducted under three different Reynolds numbers (Re) ranging from 5000 to 25,000, while nozzle-to-target surface spacings (S/d) ranged from 0.5 to 8.0. Furthermore, an assessment was made of the impact of different fin arrangements, single-row (L1), double-row (L2), and triple-row (L3), on convective heat transfer. Detailed examinations were performed on area-averaged and local Nusselt (Nu) numbers, flow properties, and the thermal performance criterion (TPC) on finned and smooth target surfaces. The study’s results revealed that the use of aerofoil-shaped fins and the reduction in S/d, along with surface roughening, led to significant increases in the local and area-averaged Nu numbers compared to the conventional IJAC scheme. The most notable heat transfer enhancement was observed at S/d = 0.5 utilizing extended jets and the surface design incorporating aerofoil-shaped fins. Under these specific conditions, the maximum heat transfer enhancement reached 52.81%. Moreover, the investigation also demonstrated that the highest TPC on the finned surface was achieved when S/d = 2.0 for L2 at Re = 25,000, resulting in a TPC value of 1.12. Furthermore, reducing S/d and mounting aerofoil-shaped fins on the surface yielded a more uniform heat transfer distribution on the relevant surface than IJAC with a smooth surface, ensuring a relatively more uniform heat transfer distribution to minimize the risk of localized overheating. KW - Beschaufelung KW - Kühlung KW - aerofoil-shaped fin KW - impinging jet array KW - cooling of turbine blades KW - heat transfer uniformity KW - pin-fin row KW - Wärmeübertragung KW - Turbine Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46387 SN - 1996-1073 VL - 17 IS - 5 PB - MDPI ER - TY - JOUR A1 - Rückert, Frank Ulrich A1 - Ibrar, Burhan A1 - Ahmed, Arslan A1 - Allweyer, Benjamin A1 - Hübner, Dirk A1 - Klinger, Friedrich A1 - Knaus, Hermann A1 - Benim, Ali Cemal T1 - Fluid flow and heat transfer of a novel passive cooling system for gearless wind turbines with a power range of 3–12 MW JF - Energy N2 - Today, the gearless horizontal axis wind turbines are mainstream in wind energy industry. High demands of electric power led to bigger systems and active cooling reduces the overall efficiency of the turbines. Passive cooling systems have been examined for the first time for a gearless wind energy generator with power range of 3–12 MW. With further developed heat conductors, it is possible to operate a wind generator in a larger power class with passive cooling components. This is accompanied by enormous cost savings due to elimination of costs for active cooling elements such as the use of fans, pumps, and heat exchangers. An additional factor is the significant reduction in necessary maintenance due to the minimized incidence of corrosion and wear. Design of the cooling fins and an ideal position of the generator within the housing of the wind turbine has been objectives. Mandatory is that maximum temperatures of the generator fins should stay under 155 °C, which could be reached with several designs for different heat exchanger geometries. KW - Windturbine KW - Wärmeübertragung KW - Numerische Strömungssimulation KW - Generator KW - Kühlung KW - Passive cooling KW - Gearless wind turbine Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46594 SN - 0360-5442 VL - 312 PB - Elsevier ER -