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YANGAZ, MURAT UMUT

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YANGAZ

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End date: 2024 × Has files: true ×

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Now showing 1 - 4 of 4
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    PublicationOpen Access
    Effect of air pressure on nanofiber production in solution blowing method
    (GAZI UNIV, FAC ENGINEERING ARCHITECTURE, 2020-07-21) EKİCİ, BÜLENT; Polat, Yusuf; Yangaz, Murat Umut; Calisir, Mehmet Durmus; Gul, Mehmet Zafer; Demir, Ali; Ekici, Bulent; Kilic, Ali
    In this study, effect of air pressure on nanofiber diameter and morphology was studied for solution blowing technique. A computational fluid dynamics (CFD) analysis was realized via ANSYS (R) Fluent software, and the results were compared with experimental solutions. The results showed that an increase in air inlet pressure from 100 kPa to 300 kPa has significant effect on nanofiber diameter and morphology. In contrast, as the air inlet pressure increases above 300 kPa to 600 kPa, both nanofiber diameter increases, and the fiber agglomerations are observed due to high turbulence intensity. The droplets were observed at 100 kPa air inlet pressure due to low driving force applied to the polymer solution. The effects of air pressure on nanofiber diameter and morphology have been investigated by using finite volume method, and the results are compared with the experimental results.
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    PublicationOpen Access
    Comparison of Conventional and Modified Burners in Performance with Different Fuels using a Linear and a Non-linear Eddy-viscosity Turbulence Model
    (ISFAHAN UNIV TECHNOLOGY, 2019-11-01) ÇİFTÇİOĞLU, GÖKÇEN ALEV; Yangaz, M. U.; Ciftcioglu, G. A.; Kadirgan, M. A. N.
    Energy sources must be used efficiently to provide the sufficient amount of energy for the still-growing population in the world, already threatened by the effects of global warming. The significant increase in the use of natural resources causes serious problems due to its unsustainable situation. Therefore, exhaust gases/emissions must be reduced to prevent more damage on the environment. This study aims to provide solutions for a sustainable ecosystem by lowering emissions such as CO, unburnt HC, NOx, and enhancing the combustion efficiency in a certain type/scale industrial burner. In that way, some geometric modifications (on furnace design and the connected burner) have been applied on the conventional type burners to benefit the effects of preheating of combustion air. Modified geometries have been analyzed numerically and compared with the conventional design's results. Moreover, the comparison between a linear and non-linear turbulence model has been given in terms of simulation results. Major findings indicate that Burner-1 has significantly lower emissions compared to the others. Preheating effect coupled with the flue gas recirculation (FGR) seems to work well in terms of performance and emissions. Also, a significant difference between linear and non-linear turbulence model appeared on the emission characteristics for the same simulations.
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    PublicationOpen Access
    Farklı Uygulama ve Tasarımların Bir Gaz Yakıcıdakı Emisyonların Düşürülmesine Etkileri
    (2018-09-30) ÇİFTÇİOĞLU, GÖKÇEN ALEV; MURAT UMUT YANGAZ;GÖKÇEN ALEV ÇİFTÇİOĞLU;Mehmet Arif Neşet KADIRGAN
    Verimsiz enerji kullanımı, kaynakların hızla tükenmesinin ve aynı zamanda tam yanmanın gerçekleşmediğine işaret edebilecek, yüksek orandaki emisyonlara bağlı küresel ısınmanın ana nedenlerinden biridir. Genel olarak, toplu sistemler ya da büyük ölçekli sistemler yukarda belirtilen problemlerin en büyük pay sahibidirler. Endüstriyel yakıcılar metal şekillendirme sanayisinde ve büyük ölçekli elektrik üretim süreçlerinde yaygın bir şekilde kullanılmaktadır. Bu alanlarda, hem karbon hem de azot bazlı emisyonlar için katı kurallar vardır. Buradan yola çıkarak, bu çalışma, çevresel kirleticilerin minimize edilmesi için oksi-yakıt yanması, yanmış gazların iç devirdaimi ya da ön karışımlama gibi konsept ve tasarımları içeren farklı teknikler kullanarak, yanma verimi ve emisyon düşüşü açısından iyileştirme sağlamayı amaçlamaktadır. Bütün sonuçlar birbiriyle karşılaştırılmış ve birçok parametreyi içeren tablolar ile sıcaklık konturları şeklinde verilmiştir. Bazı konseptlerin diğerlerinden performans ve emisyonlar açısından daha etkin olduğu gösterilmiştir.
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    PublicationOpen Access
    A Two-Time-Scale Turbulence Model and Its Application in Free Shear Flows
    (2024-02-01) GÜL, MEHMET ZAFER; YANGAZ, MURAT UMUT; GÜL M. Z., YANGAZ M. U., Sen S.
    A novel three-equation turbulence model has been proposed as a potential solution to overcome some of the issues related to the k–ε models of turbulence. A number of turbulence models found in the literature designed for compressed turbulence within internal combustion engine cylinders tend to exhibit limitations when applied to turbulent shear flows, such as those occurring through intake or exhaust valves of the engine. In the event that the flow is out of equilibrium where Pk deviates from ε, the turbulence models require a separate turbulence time-scale determiner along with the dissipation, ε. In the current research, this is accomplished by resolving an additional equation that accounts for turbulence time scale, τ. After presenting the rationale behind the model, its application to three types of free shear flows were given. It has been shown that the three-equation k–ε–τ model outperforms the standard k–ε model as well as a number of two-equation models in these flows. Initially, the k–ε–τ model handles the issue of the plane jet/round jet anomaly in an effective manner. Secondly, it outperforms the two-equation models in predicting the flow behavior in the case of plane wake, one that is distinguished by its weak shear form.