@article{YalcınkayaDurmazTepeetal.2024, author = {Yal{\c{c}}{\i}nkaya, Orhan and Durmaz, Ufuk and Tepe, Ahmet {\"U}mit and Benim, Ali Cemal and Uysal, {\"U}nal}, title = {Heat and Flow Characteristics of Aerofoil-Shaped Fins on a Curved Target Surface in a Confined Channel for an Impinging Jet Array}, series = {Energies}, volume = {17}, journal = {Energies}, number = {5}, publisher = {MDPI}, issn = {1996-1073}, doi = {10.3390/en17051238}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-46387}, pages = {21}, year = {2024}, abstract = {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.}, subject = {Beschaufelung}, language = {en} } @article{ShajahanBenim2026, author = {Shajahan, Mohamed Iqbal and Benim, Ali Cemal}, title = {Granular PCM based heat sink for electronics thermal management}, series = {Applied Thermal Engineering}, volume = {286}, journal = {Applied Thermal Engineering}, publisher = {Elsevier}, issn = {1359-4311}, doi = {10.1016/j.applthermaleng.2025.129336}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-59649}, year = {2026}, abstract = {This study investigates aluminum heat sinks integrated with GR42 phase change material (PCM), aiming to enhance thermal inertia and stabilize device temperatures. This is important, since the increasing miniaturization and performance demands for electronic devices have led in a growing need for advanced thermal management systems capable of handling rapid transient loads. The novelty of the work lies in examining different heat sink layouts that optimize the heat dissipation capabilities of GR42 PCMs while minimizing size and weight for electronic cooling. The experimental testing was conducted using three configurations, namely no fin, circular fin and hexagonal fin, with three input powers (4 W, 8 W, and 12 W). The experimental results show that the hexagonal-fin heat sink, surface area is 25 \% more than circular fins, exhibited superior thermal performance without significant variation in input power. Notably, the hexagonal-fin heat sink achieved the desired set point temperature of 55 ◦C in 33 \% less time than the circular-fin design and 45 \% less time than the heat sink without fins. Furthermore, the peak temperatures increased up to 21 \% for circular fins. During the charging cycles, the enhancement ratios vary from 72 \% and begin to narrow to 25 \% during discharge cycles. The hexagonal-fin configuration also exhibited superior melting dynamics, completing the phase transition 44 \% faster at higher input power than the circular fins, and established a thermal deviation of nearly 51 \% less than finless heat sinks. These findings underscore the critical role of fin geometry and PCM integration in achieving uniform temperature distribution and improved energy storage efficiency. Overall, the hexagonal-fin heat sink with GR42 PCM shows strong potential as a passive cooling solution for low-power portable electronic devices.}, language = {en} } @article{RueckertIbrarAhmedetal.2024, author = {R{\"u}ckert, Frank Ulrich and Ibrar, Burhan and Ahmed, Arslan and Allweyer, Benjamin and H{\"u}bner, Dirk and Klinger, Friedrich and Knaus, Hermann and Benim, Ali Cemal}, title = {Fluid flow and heat transfer of a novel passive cooling system for gearless wind turbines with a power range of 3-12 MW}, series = {Energy}, volume = {312}, journal = {Energy}, publisher = {Elsevier}, issn = {0360-5442}, doi = {10.1016/j.energy.2024.133478}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-46594}, year = {2024}, abstract = {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.}, subject = {Windturbine}, language = {en} } @article{Benim1989, author = {Benim, Ali Cemal}, title = {Finite element solution of an enclosed turbulent diffusion flame}, series = {International Journal for Numerical Methods in Fluids}, volume = {9}, journal = {International Journal for Numerical Methods in Fluids}, number = {3}, publisher = {Wiley}, issn = {0271-2091}, doi = {10.1002/fld.1650090305}, pages = {289 -- 303}, year = {1989}, abstract = {A finite element formulation of enclosed turbulent diffusion flames is presented. A primitive variables approach is preferred in the analysis. A mixed interpolation is employed for the velocity and pressure. In the solution of the Navier-Stokes equations, a segregated formulation is adopted, where the pressure discretization equation is obtained directly from the discretized continuity equation, considering the velocity-pressure relationships in the discretized momentum equations. The state of turbulence is defined by a κ-ϵ model. Near solid boundaries, a wall function approach is employed. The combustion rates are estimated using the eddy dissipation concept. The expensive direct treatment of the integrodifferential equations of radiation is avoided by employing the moment method, which allows the derivation of an approximate local field equation for the radiation intensity. The proposed finite element model is verified by investigating a technical turbulent diffusion flame of semi-industrial size, and comparing the results with experiments and finite difference predictions.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{Benim1990, author = {Benim, Ali Cemal}, title = {Finite element analysis of confined turbulent swirling flows}, series = {International Journal for Numerical Methods in Fluids}, volume = {11}, journal = {International Journal for Numerical Methods in Fluids}, number = {6}, publisher = {Wiley}, issn = {0271-2091}, doi = {10.1002/fld.1650110602}, pages = {697 -- 717}, year = {1990}, abstract = {The finite element method is applied to incompressible and statistically steady confined turbulent swirling flows. A velocity-pressure formulation is employed. The momentum and continuity equations are solved using a segregated algorithm. Two turbulence models, namely the standard κ-ε model and the algebraic stress model, are considered. It is shown that the algebraic stress model leads to significantly more accurate results in swirling flows compared to the κ-ε model. A novel way of implementing the algebraic stress model is presented in which the stresses are coupled to the Navier-Stokes equations in such a way that they 'correct' the effective viscosity hypothesis. This formulation seems to provide a convenient approach for finite elements. In deriving the discretization equations, a streamline-upwind/Petrov-Galerkin method is employed. Comparisons performed between various upwind schemes show that the numerical solution may be substantially affected by the particular upwind procedure used. The analysis is extended to the prediction of particle motion in turbulent swirling flow fields. Here the fluid turbulence is modelled adopting a stochastic approach. The influence of turbulence modelling on particle movement is investigated.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{BiswasMandalBoseetal.2023, author = {Biswas, Nirmalendu and Mandal, Dipak Kumar and Bose, Sharmistha and Manna, Nirmal K. and Benim, Ali Cemal}, title = {Experimental Treatment of Solar Chimney Power Plant — A Comprehensive Review}, series = {Energies}, volume = {16}, journal = {Energies}, number = {17}, publisher = {MDPI}, issn = {1996-1073}, doi = {10.3390/en16176134}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-46139}, pages = {41}, year = {2023}, abstract = {Solar chimney power plants (SCPPs) are encouraging sustainable energy sources due to their low cost, abundance, low maintenance, and eco-friendliness. However, despite significant efforts to optimize SCPP design, their efficiency and power generation capabilities remain limited. Researchers have explored modifications in plant geometry and hybridization to improve efficiency. Despite extensive work in this area, commercialization of SCPPs has not yet been achieved. Most of the research is numerical and may differ from real-world practical use. The number of experimental studies is also relatively small. To facilitate commercialization, further investigation with practical and feasible dimensions is required. This comprehensive review paper aims to provide an in-depth analysis of experimental approaches and advancements in the field of SCPPs. The paper begins with an introduction, highlighting the background, significance, and objectives of the review. It provides an overview of the plants, discussing their principles and operation as innovative renewable energy systems. The historical development and evolution of solar chimneys are explored, shedding light on their progression over time. Case studies of operational hybrid SCPPs are examined to showcase real-world applications and performance. The paper also addresses environmental impacts and sustainability considerations associated with SCPPs. Furthermore, recommendations for future research and development in this field are provided to guide researchers and industry professionals. This study focuses on the possibility of commercialization of both standalone and hybrid SCPPs.}, subject = {Erneuerbare Energien}, language = {en} } @article{BhattacharyyaBenimChattopadhyayetal.2019, author = {Bhattacharyya, Suvanjan and Benim, Ali Cemal and Chattopadhyay, Himadri and Banerjee, Arnab}, title = {Experimental investigation of heat transfer performance of corrugated tube with spring tape inserts}, series = {Experimental Heat Transfer}, volume = {32}, journal = {Experimental Heat Transfer}, number = {5}, publisher = {Taylor \& Francis}, issn = {0891-6152}, doi = {10.1080/08916152.2018.1531955}, pages = {411 -- 425}, year = {2019}, language = {en} } @article{SulaimanSaberHasanetal.2025, author = {Sulaiman, Mohammed A. and Saber, Hindren Ali and Hasan, Hasan F. and Benim, Ali Cemal}, title = {Experimental and numerical investigation of novel dew-point evaporative cooler with shell and tube design}, series = {Energy}, volume = {317}, journal = {Energy}, publisher = {Elsevier}, issn = {0360-5442}, doi = {10.1016/j.energy.2025.134686}, year = {2025}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @unpublished{SulaimanSaberHasanetal.2024, author = {Sulaiman, Mohammed Abdulqader and Saber, Hindren Ali and Hasan, Hasan Fahmi and Benim, Ali Cemal}, title = {Experimental and Numerical Investigation of Novel Dew-Point Evaporative Cooler with Shell and Tube Design}, series = {SSRN}, journal = {SSRN}, publisher = {Elsevier}, doi = {10.2139/ssrn.4980477}, pages = {38}, year = {2024}, abstract = {Implementing a neoteric practical design for dew-point evaporative cooler (DPEC) rather than the widely utilized flat plate and corrugated plate has been challenging since the first invention. Thus far, no study has been dedicated to design and experimentally implement a shell and tube concept for DPEC with an innovative configuration that can contribute in mass production, globalization, and effortless maintenance of such a high performance cooling machine. Therefore, in this paper, the shell and tube concept has been employed as a core design for DPEC that has been reinforced by a practical approaches. The practical approaches include a dedicated novel design for the proposed system and utilizing super cheap materials for the system's construction. Both of the aforementioned approaches provide solutions for overcoming the aforementioned issues. In the meanwhile, the superiority of the proposed DPEC has been approved by comparing it to the flat plate DPEC. During the experimentations, the prototype was able to reduce the ambient temperature by up to 34.1°C (from 53°C to 18.9°C), besides, it could achieve a dew-point effectiveness of 99.6\% and wet-bulb effectiveness of 135\%.}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{BenimEscudierNahavandietal.2010, author = {Benim, Ali Cemal and Escudier, Marcel and Nahavandi, Ali and Nickson, A. K. and Syed, Khawar J. and Joos, Franz}, title = {Experimental and numerical investigation of isothermal flow in an idealized swirl combustor}, series = {International Journal of Numerical Methods for Heat \& Fluid Flow}, volume = {20}, journal = {International Journal of Numerical Methods for Heat \& Fluid Flow}, number = {3}, publisher = {Emerald}, doi = {10.1108/09615531011024084}, pages = {348 -- 370}, year = {2010}, language = {en} } @article{IqbalBenimFischeretal.2016, author = {Iqbal, Sohail and Benim, Ali Cemal and Fischer, S. and Joos, F. and Kluβ, D. and Wiedermann, Alexander}, title = {Experimental and numerical analysis of natural bio and syngas swirl flames in a model gas turbine combustor}, series = {Journal of Thermal Science}, volume = {25}, journal = {Journal of Thermal Science}, number = {5}, publisher = {Springer}, doi = {10.1007/s11630-016-0885-4}, pages = {460 -- 469}, year = {2016}, language = {en} } @article{MandalMannaBiswasetal.2026, author = {Mandal, Dipak Kumar and Manna, Nirmal K. and Biswas, Nirmalendu and Rudra, Tansu and Kumar, Rajesh and Benim, Ali Cemal}, title = {Enhanced heat transport in magneto-nanofluidic thermal systems: adiabatic block effects in grooved channels and ANN modeling}, series = {International Journal of Thermofluids}, volume = {31}, journal = {International Journal of Thermofluids}, publisher = {Elsevier}, issn = {2666-2027}, doi = {10.1016/j.ijft.2025.101515}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-60127}, year = {2026}, abstract = {This study investigates heat transfer enhancement in magneto-nanofluidic systems through the strategic placement of adiabatic blocks in grooved channels. Using CuO-H2O nanofluid in a bottom-heated channel with circular expansion, we examine the complex interactions between forced convection, magnetic fields, and uoyancy effects. Through systematic numerical analysis, we explore the combined influences of Rayleigh, Reynolds, and Hartmann numbers on thermal performance. Our findings reveal significant heat transfer enhancement (up to 137 \%) under optimal conditions, particularly with vertical magnetic field orientation at Re = 100 and Ha = 30. The results demonstrate how adiabatic blocks modify flow structures, with larger blocks diminishing vortex intensity while elevated Ra generates secondary vortices that interact with primary circulations. Magnetic field effects show notable dependence on orientation, with vertical fields generally promoting better heat transfer than horizontal configurations. To complement the numerical analysis, we develop a predictive model using Artificial Neural Network (ANN) for Nusselt numbers across various operating conditions, achieving over 99 \% accuracy. The integrated computational-ANN approach offers significant advancements in optimizing thermal systems in various areas, ranging from electronics cooling to microfluidic devices.}, language = {en} } @article{BiswasMandalMannaetal.2023, author = {Biswas, Nirmalendu and Mandal, Dipak Kumar and Manna, Nirmal K. and Benim, Ali Cemal}, title = {Enhanced energy and mass transport dynamics in a thermo-magneto-bioconvective porous system containing oxytactic bacteria and nanoparticles: cleaner energy application}, series = {Energy}, volume = {263}, journal = {Energy}, number = {B}, publisher = {Elsevier}, issn = {0360-5442}, doi = {10.1016/j.energy.2022.125775}, year = {2023}, language = {en} } @article{BhattacharyyaBhattVishwakarmaetal.2024, author = {Bhattacharyya, Suvanjan and Bhatt, Tapasvi and Vishwakarma, Devendra Kumar and Benim, Ali Cemal and Abraham, John}, title = {Effect of mechanical vibration and its influence on thermal performance of a nanofluid heat exchanger}, series = {Numerical Heat Transfer: An International Journal of Computation and Methodology, Part A: Applications}, journal = {Numerical Heat Transfer: An International Journal of Computation and Methodology, Part A: Applications}, publisher = {Informa}, issn = {1040-7782}, doi = {10.1080/10407782.2024.2331589}, pages = {1 -- 24}, year = {2024}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{XiaSmithBenimetal.1997, author = {Xia, Jiliang and Smith, Brian L. and Benim, Ali Cemal and Schmidli, Jiirg and Yadigaroglu, George}, title = {Effect of inlet and outlet boundary conditions on swirling flows}, series = {Computers \& Fluids}, volume = {26}, journal = {Computers \& Fluids}, number = {8}, publisher = {Elsevier}, issn = {0045-7930}, doi = {10.1016/S0045-7930(97)00026-1}, pages = {811 -- 823}, year = {1997}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{AichBarghaviBenim2025, author = {Aich, Rishav and Barghavi, Devarakonda and Benim, Ali Cemal}, title = {Effect of hydrodynamic and thermal anisotropy on convective heat transfer in a fluid saturated porous duct: A finite volume approach}, series = {Numerical Heat Transfer: An International Journal of Computation and Methodology, Part A: Applications}, journal = {Numerical Heat Transfer: An International Journal of Computation and Methodology, Part A: Applications}, publisher = {Taylor \& Francis}, issn = {1521-0634}, doi = {10.1080/10407782.2025.2527971}, pages = {22}, year = {2025}, subject = {Numerische Str{\"o}mungssimulation}, language = {de} } @article{BaşaranBenim2024, author = {Ba{\c{s}}aran, An{\i}l and Benim, Ali Cemal}, title = {Development of Correlations Based on CFD Study for Microchannel Condensation Flow of Environmentally Friendly Hydrocarbon Refrigerants}, series = {Energies}, volume = {17}, journal = {Energies}, number = {7}, publisher = {MDPI}, issn = {1996-1073}, doi = {10.3390/en17071531}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-46398}, pages = {21}, year = {2024}, abstract = {A CFD simulation of the condensation flow of R600a and R290 within microchannels was conducted to explore the effect of mass flux, hydraulic diameter, and vapour quality on heat transfer rate and pressure drop. Data obtained from CFD simulations were used to develop new heat transfer and pressure drop correlations for the condensation flows of R600a and R290, which are climate-friendly refrigerants. Steady-state numerical simulations of condensation flow of refrigerants were carried out inside a single circular microchannel with diameters varying between 0.2 and 0.6 mm. The volume of fluid approach was used in the proposed model, calculating the interface phase change using the Lee model. The CFD simulation model was validated via a comparison of the simulation results with the experimental data available in the literature. It is found that the newly developed Nu number correlation shows a deviation, with an Ave-MAE of 11.16\%, compared to those obtained by CFD simulation. Similarly, the deviation between friction factors obtained by the newly proposed correlation and those obtained by CFD simulation is 20.81\% Ave-MAE. Widely recognized correlations that are applicable to the condensation of refrigerants within small-scale channels were also evaluated by comparing newly developed correlations. It is concluded that the newly proposed correlation has a higher accuracy in predicting the heat transfer coefficient and pressure drop. This situation can contribute to the creation of a sustainable system via the use of microchannels and climate-friendly refrigerants, like R600a and R290.}, subject = {Druckabfall}, language = {en} } @article{EblingKrummPfeiffelmannetal.2016, author = {Ebling, Dirk and Krumm, A. and Pfeiffelmann, Bj{\"o}rn and Gottschald, J. and Bruchmann, J. and Benim, Ali Cemal and Adam, Mario and Labs, R. and Herbertz, R. R. and Stunz, A.}, title = {Development of a System for Thermoelectric Heat Recovery from Stationary Industrial Processes}, series = {Journal of Electronic Materials}, volume = {45}, journal = {Journal of Electronic Materials}, number = {7}, publisher = {Springer}, doi = {10.1007/s11664-016-4511-8}, pages = {3433 -- 3439}, year = {2016}, language = {de} } @inproceedings{RueckertBurhanAhmedetal.2024, author = {R{\"u}ckert, Frank Ulrich and Burhan, Ibrar and Ahmed, Arslan and H{\"u}bner, Dirk and Allweyer, Benjamin and Klinger, Friedrich and Benim, Ali Cemal}, title = {Development of a Passive Cooling System for a Gearless Wind Energy Generator}, series = {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, D{\"u}sseldorf, Germany}, volume = {1}, booktitle = {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, D{\"u}sseldorf, Germany}, publisher = {Springer Nature}, address = {Cham}, isbn = {9783031672408}, issn = {2195-4356}, doi = {10.1007/978-3-031-67241-5_30}, pages = {333 -- 343}, year = {2024}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{BaşaranBenim2024, author = {Ba{\c{s}}aran, An{\i}l and Benim, Ali Cemal}, title = {Condensation Flow of Refrigerants Inside Mini and Microchannels: A Review}, series = {Applied Sciences}, volume = {14}, journal = {Applied Sciences}, number = {7}, publisher = {MDPI}, issn = {2076-3417}, doi = {10.3390/app14072988}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-46358}, year = {2024}, abstract = {Nowadays, the demand for obtaining high heat flux values in small volumes has increased with the development of technology. Condensing flow inside mini- and microchannels has been becoming a promising solution for refrigeration, HVAC, air-conditioning, heat pumps, heat pipes, and electronic cooling applications. In these applications, employing mini/microchannels in the condenser design results in the working fluid, generally refrigerant, undergoing a phase change inside the mini/microchannels. On the other hand, the reduction in the hydraulic diameter during condensation gives rise to different flow regimes and heat transfer mechanisms in the mini- and microchannels compared to the conventional channels. Therefore, the understanding of fluid flow and heat transfer characteristics during condensation of refrigerant inside mini- and microchannels has been gaining importance in terms of condenser design. This study presents a state-of-the-art review of condensation studies on refrigerants inside mini- and microchannels. The review includes experimental studies as well as correlation models, which are developed to predict condensation heat transfer coefficients and pressure drop. The refrigerant type, thermodynamical performance, and compatibility, as well as the environmental effects of refrigerant, play a decisive role in the design of refrigeration systems. Therefore, the environmental impacts of refrigerants and current regulations against them are also discussed in the present review.}, subject = {Kondensation}, language = {en} } @article{BenimOzkanCaganetal.2007, author = {Benim, Ali Cemal and Ozkan, K. and Cagan, M. and Gunes, D.}, title = {Computational investigation of turbulent jet impinging onto rotating disk}, series = {International Journal of Numerical Methods for Heat \& Fluid Flow}, volume = {17}, journal = {International Journal of Numerical Methods for Heat \& Fluid Flow}, number = {3}, publisher = {Emerald}, doi = {10.1108/09615530710730157}, pages = {284 -- 301}, year = {2007}, language = {en} } @article{BenimBrillertCagan2004, author = {Benim, Ali Cemal and Brillert, Dieter and Cagan, Markos}, title = {Computational investigation of the flow in pre-swirl stator-rotor systems}, series = {International Journal of Computational Methods}, volume = {1}, journal = {International Journal of Computational Methods}, number = {2}, publisher = {World Scientific}, issn = {0219-8762}, doi = {10.1142/S0219876204000125}, pages = {329 -- 343}, year = {2004}, abstract = {A 3D computational analysis has been applied to investigate direct transfer, pre-swirl systems for gas turbine cooling. Alternative computational procedures have been applied and results have been compared with measurements. Based on these validation studies, strategies for modeling such systems have been proposed. Present results suggest that sufficiently accurate predictions can be obtained using a quasi-steady analysis applying the "frozen rotor" approach for treating the interface between the stationary and rotating domains.}, subject = {Gasturbine}, language = {en} } @article{BenimCanalBoke2022, author = {Benim, Ali Cemal and Canal, Cansu Deniz and Boke, Yakup Erhan}, title = {Computational investigation of oxy-combustion of pulverized coal and biomass in a swirl burner}, series = {Energy}, volume = {238}, journal = {Energy}, number = {C}, publisher = {Elsevier}, issn = {0360-5442}, doi = {10.1016/j.energy.2021.121852}, year = {2022}, language = {en} } @article{BenimKorucu2023, author = {Benim, Ali Cemal and Korucu, Ayse}, title = {Computational investigation of non-premixed hydrogen-air laminar flames}, series = {International Journal of Hydrogen Energy}, volume = {48}, journal = {International Journal of Hydrogen Energy}, number = {38}, publisher = {Elsevier}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2022.12.248}, pages = {14492 -- 14510}, year = {2023}, subject = {Wasserstoff}, language = {en} } @article{PfeiffelmannBenimJoos2021, author = {Pfeiffelmann, Bj{\"o}rn and Benim, Ali Cemal and Joos, Franz}, title = {Computational Investigation of Impingement Cooling of Thermoelectric Generators}, series = {Heat Transfer Engineering}, volume = {42}, journal = {Heat Transfer Engineering}, number = {3-4}, publisher = {Taylor \& Francis}, issn = {0145-7632}, doi = {10.1080/01457632.2019.1699296}, pages = {282 -- 295}, year = {2021}, language = {en} } @article{BenimFrankAssmannetal.2019, author = {Benim, Ali Cemal and Frank, Thiemo and Assmann, Alexander and Lichtenberg, Artur and Akhyari, Payam}, title = {Computational investigation of hemodynamics in hardshell venous reservoirs: A comparative study}, series = {Artificial Organs}, volume = {44}, journal = {Artificial Organs}, number = {4}, publisher = {Wiley}, issn = {1525-1594}, doi = {10.1111/aor.13593}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-29070}, pages = {411 -- 418}, year = {2019}, abstract = {Extracorporeal circulation using heart-lung-machines is associated with a profound activation of corpuscular and plasmatic components of circulating blood, which can also lead to deleterious events such as systemic inflammatory response and hemolysis. Individual components used to install the extracorporeal circulation have an impact on the level of activation, most predominantly membrane oxygenators and hardshell venous reservoirs as used in extracorporeal systems. The blood flows in two different hardshell reservoirs are computationally investigated. A special emphasis is placed on the prediction of an onset of transition and turbulence generation. Reynolds-averaged numerical simulations (RANS) based on a transitional turbulence model, as well as large eddy simulations (LES) are applied to achieve an accurate prediction. In the LES analysis, the non-Newtonian behavior of the blood is considered via the Carreau model. Blood damage potential is quantified applying the Modified Index of Hemolysis (MIH) based on the predicted flow fields. The results indicate that the flows in both reservoirs remain predominantly laminar. For one of the reservoirs, considerable turbulence generation is observed near the exit site, caused by the specific design for the connection with the drainage tube. This difference causes the MIH of this reservoir to be nearly twice as large as compared to the alternative design. However, a substantial improvement of these performance criteria can be expected by a local geometry modification.}, language = {en} } @article{BhattacharyyaChattopadhyayBenim2017, author = {Bhattacharyya, Suvanjan and Chattopadhyay, Himadri and Benim, Ali Cemal}, title = {Computational investigation of heat transfer enhancement by alternating inclined ribs in tubular heat exchanger}, series = {Progress in Computational Fluid Dynamics}, volume = {17}, journal = {Progress in Computational Fluid Dynamics}, number = {6}, publisher = {Inderscience Enterprises Limited}, issn = {1468-4349}, doi = {10.1504/PCFD.2017.088818}, pages = {390 -- 396}, year = {2017}, language = {en} } @article{BenimPfeiffelmannOcłońetal.2019, author = {Benim, Ali Cemal and Pfeiffelmann, Bj{\"o}rn and Ocłoń, Paweł and Taler, Jan}, title = {Computational investigation of a lifted hydrogen flame with LES and FGM}, series = {Energy}, volume = {173}, journal = {Energy}, publisher = {Elsevier}, issn = {0360-5442}, doi = {10.1016/j.energy.2019.02.133}, pages = {1172 -- 1181}, year = {2019}, language = {en} } @article{AliFarooqShahzadetal.2022, author = {Ali, Ramzan and Farooq, A. and Shahzad, A. and Benim, Ali Cemal and Iqbal, A. and Razzaq, M.}, title = {Computational approach on three-dimensional flow of couple-stress fluid with convective boundary conditions}, series = {Physica A: Statistical Mechanics and its Applications}, volume = {553}, journal = {Physica A: Statistical Mechanics and its Applications}, publisher = {Elsevier}, issn = {0378-4371}, doi = {10.1016/j.physa.2019.124056}, year = {2022}, language = {en} } @article{BenimDiederichGueletal.2018, author = {Benim, Ali Cemal and Diederich, Michael and G{\"u}l, Fethi and Oclon, Pawel and Taler, Jan}, title = {Computational and experimental investigation of the aerodynamics and aeroacoustics of a small wind turbine with quasi-3D optimization}, series = {Energy Conversion and Management}, volume = {177}, journal = {Energy Conversion and Management}, publisher = {Elsevier}, doi = {10.1016/j.enconman.2018.09.042}, pages = {143 -- 149}, year = {2018}, language = {en} } @inproceedings{OezmanGuelDiederichetal.2022, author = {{\"O}zman, Cansu and G{\"u}l, Fethi and Diederich, Michael and Benim, Ali Cemal and Janoske, Uwe}, title = {Computational and Experimental Investigation of Flow and Convective Heat Transfer along Rough Surfaces}, series = {Proceedings of CONV-22: Int. Symp. on Convective Heat and Mass Transfer June 5 - 10, 2022, Turkey}, booktitle = {Proceedings of CONV-22: Int. Symp. on Convective Heat and Mass Transfer June 5 - 10, 2022, Turkey}, publisher = {Begellhouse}, doi = {10.1615/ICHMT.2022.CONV22.590}, pages = {447 -- 454}, year = {2022}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{PfeiffelmannDiederichGueletal.2020, author = {Pfeiffelmann, Bj{\"o}rn and Diederich, Michael and G{\"u}l, Fethi and Benim, Ali Cemal and Heese, Markus and Hamberger, Andreas}, title = {Computational and Experimental Investigation of an Industrial Biomass Furnace}, series = {Chemical Engineering \& Technology}, volume = {43}, journal = {Chemical Engineering \& Technology}, number = {8}, publisher = {Wiley}, issn = {1521-4125}, doi = {10.1002/ceat.201900637}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-27747}, pages = {1538 -- 1546}, year = {2020}, language = {en} } @article{BenimCaganGuenes2004, author = {Benim, Ali Cemal and Cagan, Markos and G{\"u}nes, Dogan}, title = {Computational analysis of transient heat transfer in turbulent pipe flow}, series = {International Journal of Thermal Sciences}, volume = {43}, journal = {International Journal of Thermal Sciences}, number = {8}, publisher = {Elsevier}, issn = {1290-0729}, doi = {https://doi.org/10.1016/j.ijthermalsci.2004.02.012}, pages = {725 -- 732}, year = {2004}, subject = {Turbulenzmodell}, language = {en} } @article{DenizCanalBokeAydinetal.2021, author = {Deniz Canal, Cansu and Boke, Yakup Erhan and Aydin, Ozer and Benim, Ali Cemal}, title = {COMPUTATIONAL ANALYSIS OF PULVERIZED COAL CO-FIRING WITH BIOMASS IN 150MWe UNIT OF TUNCBILEK THERMAL POWER PLANT}, series = {Isi Bilimi ve Teknigi Dergisi - Journal of Thermal Science and Technology}, volume = {41}, journal = {Isi Bilimi ve Teknigi Dergisi - Journal of Thermal Science and Technology}, number = {1}, publisher = {Turkish Society for Thermal Sciences \& Technology}, issn = {1300-3615}, doi = {10.47480/isibted.979314}, pages = {37 -- 50}, year = {2021}, language = {en} } @article{BenimEscudierNahavandietal.2011, author = {Benim, Ali Cemal and Escudier, M. P. and Nahavandi, A. and Nickson, A. K. and Syed, Khawar J. and Joos, F.}, title = {Computational analysis of incompressible turbulent flow in an idealised swirl combustor}, series = {Progess in Computational Fluid Dynamics, An International Journal}, volume = {11}, journal = {Progess in Computational Fluid Dynamics, An International Journal}, number = {1}, publisher = {inderscience}, doi = {10.1504/pcfd.2011.037571}, pages = {42 -- 45}, year = {2011}, language = {en} } @article{SShajahanRetal.2026, author = {S, Kasiviswanathan and Shajahan, Mohamed Iqbal and R, Bharathiraja and Murali, Arun Prasad and Benim, Ali Cemal}, title = {Comprehensive overview of phase change materials in electronics, building, and solar applications}, series = {Engineering Research Express}, volume = {8}, journal = {Engineering Research Express}, number = {3}, publisher = {IOP Publishing}, issn = {2631-8695}, doi = {10.1088/2631-8695/ae342a}, year = {2026}, abstract = {Phase change materials (PCMs) are a viable way to improve energy efficiency and thermal control in a variety of sectors. With an emphasis on their function in thermal control, this review article offers an in-depth review of PCM applications in electronics, buildings and solar energy systems. PCMs are used in electronics to control device temperatures, which lowers the risk of overheating and increases operational efficiency by 10\% to 25\%. Through latent heat storage and release in reaction to temperature changes, PCMs are incorporated into walls, floors, and roofs in building applications to improve thermal comfort and cut energy use by 15\% to 30\%. By storing thermal energy for steady power generation, PCMs increase the dependability and efficiency of solar energy systems by 8\%-20\%. This review examines the basic ideas behind PCMs, assesses various PCM (such as organic, inorganic, and eutectic PCMs), and details about real-world applications in these energy management fields. Important issues are examined, such as material compatibility, cost-effectiveness, and long-term stability. In order to maximize performance in these crucial applications, the conclusion emphasizes the need for improvements in cost-effective PCM formulations for the improved thermal conductivity (0.2-0.7 W m-1·K-1), and adaptive control systems.}, subject = {Energieeffizienz}, language = {en} } @article{BenimPfeiffelmann2020, author = {Benim, Ali Cemal and Pfeiffelmann, Bj{\"o}rn}, title = {Comparison of Combustion Models for Lifted Hydrogen Flames within RANS Framework}, series = {Energies}, volume = {13}, journal = {Energies}, number = {1}, publisher = {MDPI}, issn = {1996-1073}, doi = {10.3390/en13010152}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-27727}, pages = {152}, year = {2020}, language = {en} } @article{BenimCicek2023, author = {Benim, Ali Cemal and {\c{C}}i{\c{c}}ek, Ayd{\i}n}, title = {Comparative analysis of water and carbon dioxide injection for the thermohydraulics of an EGS project in Dikili Geothermal Field, T{\"u}rkiye}, series = {Bulletin Of The Mineral Research and Exploration}, volume = {171}, journal = {Bulletin Of The Mineral Research and Exploration}, publisher = {Maden Tetkik ve Arama Genel M{\"u}d{\"u}rl{\"u}ğ{\"u}}, issn = {0026-4563}, doi = {10.19111/bulletinofmre.1288731}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-49115}, pages = {91 -- 105}, year = {2023}, abstract = {A comparative numerical analysis of the thermohydraulics of an enhanced geothermal system (EGS) project in T{\"u}rkiye in Dikili area is presented. The fractured granodiorite is modelled as porous media, utilizing the numerically suggested data of other authors for the corresponding hydraulic characteristics. As the heat transmission fluid, two different mediums are alternatively considered. These are the more classical medium, water and the supercritical Carbon Dioxide (sCO2). Transient calculations are performed for a time period of twenty years, comparing the temporally developing results obtained for water and sCO2 with each other. Based on modeling parameters and assumptions, higher production temperatures are observed with sCO2, in comparison to water, implying an advantage for sCO2 usage as a working fluid in EGS. This is accompanied by the further advantage of a lower pressure drop for sCO2. On the other hand, the temperature advantage is relativized by the lower specific heat capacity of sCO2 causing a decrease in the production thermal power. In general, the present re found to be encouraging for a further and more detailed analysis of the employment of sCO2 as working fluid in EGS.}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{ZenginErdoğanBenim2024, author = {Zengin, İbrahim and Erdoğan, Beytullah and Benim, Ali Cemal}, title = {CFD and Taguchi based optimization of air driven single stage partial admission axial turbine blade profiles}, series = {Energy}, volume = {290}, journal = {Energy}, publisher = {Elsevier}, issn = {0360-5442}, doi = {10.1016/j.energy.2024.130333}, pages = {13}, year = {2024}, subject = {Taguchi-Methode}, language = {en} } @article{EppleFivelandKrohmeretal.2005, author = {Epple, Bernd and Fiveland, Woody and Krohmer, Bernd and Richards, Galen and Benim, Ali Cemal}, title = {Assessment of two-phase flow models for the simulation of pulverized coald combustion}, series = {Clean Air: International Journal on Energy for a Clean Environment}, volume = {6}, journal = {Clean Air: International Journal on Energy for a Clean Environment}, number = {3}, publisher = {Begell House}, issn = {1561-4417}, doi = {10.1615/InterJEnerCleanEnv.v6.i3.50}, pages = {267 -- 287}, year = {2005}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{PfeiffelmannOzmanBenimetal.2022, author = {Pfeiffelmann, Bjorn and Ozman, Cansu and Benim, Ali Cemal and Joos, Franz}, title = {Analysis of the effect of nonuniform surface temperature distribution on the performance of a thermoelectric generator}, series = {Sustainable Energy Technologies and Assessments}, volume = {53}, journal = {Sustainable Energy Technologies and Assessments}, number = {A}, publisher = {Elsevier}, issn = {2213-1388}, doi = {10.1016/j.seta.2022.102375}, year = {2022}, language = {en} } @article{BenimNeuhoff1993, author = {Benim, Ali Cemal and Neuhoff, H. G.}, title = {Analysis of erosion behaviour in a turbocharger radial turbine}, series = {International Journal for Numerical Methods in Fluids}, volume = {16}, journal = {International Journal for Numerical Methods in Fluids}, number = {4}, publisher = {Wiley}, issn = {0271-2091}, doi = {10.1002/fld.1650160402}, pages = {259 -- 285}, year = {1993}, abstract = {An analysis of the erosion behaviour of a turbocharger radial turbine is presented. The solution domain includes both sides of the radial turbine scroll with double intake and the rotor channel. In the analysis a dilute gas-particle flow assumption is employed. The gas turbulence is defined by the k-ε model. In solving the gas phase equation, the computer code Harwell-FLOW3D is employed, which is based on a finite volume formulation using non-orthogonal body-fitted structured gridding and a pressure correction method. The particle phase is described by a Lagrangian approach, while particle paths are computed deterministically, neglecting the turbulent dispersion. For the computation of particle trajectories the code PTRACK is employed, which has been developed at ABB. Computations are carried out for several particle size classes. The results show that particles are thrown back into the scroll by the rotor at high rates. This seems to be the main source of erosion effects in the scroll. It has been observed that particles are unequally distributed between the scroll sides on their re-entry, resulting in greater erosion on one of the scroll sides. The maximum erosion along the scroll is found to be likely to occur near the scroll end.}, subject = {Erosion}, language = {en} } @article{PfeiffelmannDiederichGueletal.2019, author = {Pfeiffelmann, Bj{\"o}rn and Diederich, Michael and G{\"u}l, Fethi and Benim, Ali Cemal and Hamberger, Andreas and Heese, Markus}, title = {Analysis of combustion, heat and fluid flow in a biomass furnace}, series = {E3S Web of Conferences}, volume = {128}, journal = {E3S Web of Conferences}, publisher = {edp sciences}, issn = {2267-1242}, doi = {10.1051/e3sconf/201912803003}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-27880}, year = {2019}, language = {en} } @article{MandalBiswasMannaetal.2024, author = {Mandal, Dipak Kumar and Biswas, Nirmalendu and Manna, Nirmal K. and Gayen, Dilip Kumar and Benim, Ali Cemal}, title = {An application of artificial neural network (ANN) for comparative performance assessment of solar chimney (SC) plant for green energy production}, series = {Scientific Reports}, volume = {14}, journal = {Scientific Reports}, number = {1}, publisher = {Springer Nature}, issn = {2045-2322}, doi = {10.1038/s41598-023-46505-1}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-45190}, year = {2024}, abstract = {This study aims to optimize the power generation of a conventional Manzanares solar chimney (SC) plant through strategic modifications to the collector inlet height, chimney diameter, and chimney divergence. Employing a finite volume-based solver for numerical analysis, we systematically scrutinize influential geometric parameters, including collector height (hi = 1.85 to 0.1 m), chimney inlet diameter (dch = 10.16 to 55.88 m), and chimney outlet diameter (do = 10.16 to 30.48 m). Our findings demonstrate that reducing the collector inlet height consistently leads to increased power output. The optimal collector inlet height of hi = 0.2 m results in a significant power increase from 51 to 117.42 kW (~ 2.3 times) without additional installation costs, accompanied by an efficiency of 0.25\%. Conversely, enlarging the chimney diameter decreases the chimney base velocity and suction pressure. However, as turbine-driven power generation rises, the flow becomes stagnant beyond a chimney diameter of 45.72 m. At this point, power generation reaches 209 kW, nearly four times greater than the Manzanares plant, with an efficiency of 0.44\%. Nevertheless, the cost of expanding the chimney diameter is substantial. Furthermore, the impact of chimney divergence is evident, with power generation, collector efficiency, overall efficiency, and collector inlet velocity all peaking at an outer chimney diameter of 15.24 m (corresponding to an area ratio of 2.25). At this configuration, power generation increases to 75.91 kW, approximately 1.5 times more than the initial design. Remarkably, at a low collector inlet height of 0.2 m, combining it with a chimney diameter of 4.5 times the chimney inlet diameter (4.5dch) results in an impressive power output of 635.02 kW, signifying a substantial 12.45-fold increase. To model the performance under these diverse conditions, an artificial neural network (ANN) is effectively utilized.}, language = {en} } @article{BenimDiederichPfeiffelmann2018, author = {Benim, Ali Cemal and Diederich, Michael and Pfeiffelmann, Bj{\"o}rn}, title = {Aerodynamic Optimization of Airfoil Profiles for Small Horizontal Axis Wind Turbines}, series = {Computation}, volume = {6}, journal = {Computation}, number = {2}, publisher = {MDPI}, issn = {2079-3197}, doi = {10.3390/computation6020034}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-25143}, year = {2018}, language = {en} } @article{BenimCanalBoke2021, author = {Benim, Ali Cemal and Canal, Cansu Deniz and Boke, Yakup Erhan}, title = {A Validation Study for RANS Based Modelling of Swirling Pulverized Fuel Flames}, series = {Energies}, volume = {14}, journal = {Energies}, number = {21}, publisher = {MDPI}, issn = {1996-1073}, doi = {10.3390/en14217323}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-37365}, year = {2021}, abstract = {A swirling pulverized coal flame is computationally investigated. A Eulerian-Lagrangian formulation is used to describe the two-phase flow. Turbulence is modelled within a RANS (Reynolds averaged numerical simulation) framework. Four turbulence viscosity- (TV) based models, namely the standard k-ε model, realizable k-ε model, renormalization group theory k-ε model, and the shear stress transport k-ω model are used. In addition, a Reynolds stress transport model (RSM) is employed. The models are assessed by comparing the predicted velocity fields with the measurements of other authors. In terms of overall average values, the agreement of the predictions to the measurements is observed to be within the range 20-40\%. A better performance of the RSM compared to the TV models is observed, with a nearly twice as better overall agreement to the experiments, particularly for the swirl velocity. In the second part of the investigation, the resolution of the discrete particle phase in modelling the turbulent particle dispersion (TPD) and particle size distribution (SD) is investigated. Using the discrete random walk model for the TPD, it is shown that even five random walks are sufficient for an accuracy that is quite high, with a less than 1\% mean deviation from the solution obtained by thirty random walks. The approximation of the measured SD is determined by a continuous Rosin-Rammler distribution function, and inaccuracies that can occur in its subsequent discretization are demonstrated and discussed. An investigation on the resolution of the SD by discrete particle size classes (SC) indicates that 12 SC are required for an accuracy with a less than 1\% mean deviation from the solution with 18 SC. Although these numbers may not necessarily be claimed to be sufficiently universal, they may serve as guidance, at least for SD with similar characteristics}, language = {en} } @article{MabroukNajiBenimetal.2022, author = {Mabrouk, Riheb and Naji, Hassane and Benim, Ali Cemal and Dhahri, Hacen}, title = {A State of the Art Review on Sensible and Latent Heat Thermal Energy Storage Processes in Porous Media: Mesoscopic Simulation}, series = {Applied Sciences}, volume = {12}, journal = {Applied Sciences}, number = {14}, publisher = {MDPI}, doi = {10.3390/app12146995}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-40343}, year = {2022}, language = {en} } @article{BenimZinser1986, author = {Benim, Ali Cemal and Zinser, Walter}, title = {A segregated formulation of Navier-Stokes equations with finite elements}, series = {Computer Methods in Applied Mechanics and Engineering}, volume = {57}, journal = {Computer Methods in Applied Mechanics and Engineering}, number = {2}, publisher = {Elsevier}, issn = {0045-7825}, doi = {10.1016/0045-7825(86)90015-0}, pages = {223 -- 237}, year = {1986}, subject = {Navier-Stokes-Gleichung}, language = {en} } @article{BenimCicekEker2018, author = {Benim, Ali Cemal and {\c{C}}i{\c{c}}ek, Ayd{\i}n and Eker, Arif Mert}, title = {A numerical analysis of the thermohydraulics of an EGS project in Turkey}, series = {MATEC Web of Conferences}, volume = {240}, journal = {MATEC Web of Conferences}, publisher = {edp sciences}, issn = {2261-236X}, doi = {10.1051/matecconf/201824005001}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-27910}, year = {2018}, language = {en} } @article{AslanNahavandiTaymazetal.2012, author = {Aslan, Erman and Nahavandi, A. and Taymaz, I. and Benim, Ali Cemal}, title = {A note on modelling non-rectangular boundaries by the Lattice Boltzmann Method}, series = {Progress in Computational Fluid Dynamics, An International Journal}, volume = {12}, journal = {Progress in Computational Fluid Dynamics, An International Journal}, number = {6}, publisher = {inderscience}, doi = {10.1504/pcfd.2012.049815}, pages = {433 -- 438}, year = {2012}, language = {en} }