Erhan Böke

Determination Of Effective Thermal Conduciıvity Of Thermal Barrier Coatings By Analytical Method

Isı geçiş problemlerinde ısı iletim katsayısı önemli rol oynamaktadır. Heterojen veya kompozit ma... more Isı geçiş problemlerinde ısı iletim katsayısı önemli rol oynamaktadır. Heterojen veya kompozit malzemelerin etkin ısı iletim katsayısının modellenmesi, ısı transfer uygulamalarında ilgi duyulan bir alandır. Literatürde etkin ısı iletim katsayısının modellenmesi için geliştirilen çok sayıda eşitlik bulunmaktadır. Isıl engelleyici kaplamalarının ısıl özellikleri, kaplama malzemesinin ısıl özelliklerine, kullanılan kaplama tekniğine ve işlem parametrelerine bağlı olarak değişmektedir. Bu faktörler kaplama içinde bulunan gözeneklerin şeklini ve yönünü etkilemektedir. Bu çalışmada ısıl engelleyici kaplamalarda ısı iletim katsayısı literatürde yer alan farklı analitik ifadeler kullanılarak tayin edilmiştir. Hesaplanan etkin ısı iletim katsayısı değerleri, literatürden elde edilen deneysel sonuçlar ve CFD (Computational Fluid Dynamics) analizi ile hesaplanan değerlerle karşılaştırılmıştır. Ayrıca % 12 gözeneklilik için CFD analizi ile hesaplanan etkin ısı iletim katsayısı değerleri, literatürde aynı gözeneklilik oranı için lazer-flaş yöntemi ile elde edilmiş deneysel sonuçlar ile kıyaslanmıştır. Deneysel sonuçlar ile CFD analizi ile elde edilen sonuçlar arasında yaklaşık % 17 oranında bir sapma olduğu tespit edilmiştir.

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Mukayese metodu kullanılarak termal bariyer kaplamasının ısı iletim katsayısının deneysel olarak tayin edilmesi / Determining the thermal conductivity of thermal barrier coatings experimentally by comparative method

Erciyes Üniversitesi Fen Bilimleri Enstitüsü Dergisi, Jun 7, 2016

Isı iletim katsayısı, Mukayese metodu, Termal bariyer kaplama ÖZET Termal Bariyer Kaplamalar (TBK... more Isı iletim katsayısı, Mukayese metodu, Termal bariyer kaplama ÖZET Termal Bariyer Kaplamalar (TBK) gaz türbinlerinin sıcak kısım parçalarında, malzemelerin yüksek sıcaklık etkilerinden korunması ve gaz türbininin veriminin artırılması amacıyla yaygın olarak kullanılmaktadır. Teknolojik geli gaz türbinlerinin çalı kullanılan TBK'ların ısıl ve mekanik dayanımlarının artırılması gerekmektedir. Isı iletim katsayısı, TBK'ların ısıl dayanımları açısından en önemli faktörlerden biridir. Bu çalışmada, atmosferik plazma sprey yöntemiyle gerçekle katsayısı mukayese metodu kullanılarak deneysel olarak incelenmi farklı gözeneklilik oranına sahip TBK için ölçüm yapılmı 321 paslanmaz çelik kullanılmı katsayısı ise Lazer ºC arasında yapılmı

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Isıl Engelleyici Kaplamaların Etkin Isı İletim Katsayısının Teorik Olarak Belirlenmesi

Is i geci s problemlerinde i s i iletim katsay i s i onemli rol oynamaktad i r. Heterojen veya ko... more Is i geci s problemlerinde i s i iletim katsay i s i onemli rol oynamaktad i r. Heterojen veya kompozit malzemelerin etkin i s i iletim katsay i s i n i n modellenmesi, i s i transfer uygulamalar i nda ilgi duyulan bir aland i r. Literaturde etkin i s i iletim katsay i s i n i n modellenmesi icin geli s tirilen cok say i da e s itlik bulunmaktad i r. Is i l engelleyici kaplamalar i n i n i s i l ozellikleri, kaplama malzemesinin i s i l ozelliklerine, kullan i lan kaplama tekni g ine ve i s lem parametrelerine ba g l i olarak de g i s mektedir. Bu faktorler kaplama icinde bulunan gozeneklerin s eklini ve yonunu etkilemektedir. Bu cal i s mada i s i l engelleyici kaplamalarda i s i iletim katsay i s i literaturde yer alan farkl i analitik ifadeler kullan i larak tayin edilmi s tir. Hesaplanan etkin i s i iletim katsay i s i de g erleri, literaturden elde edilen deneysel sonuclar ve CFD (Computational Fluid Dynamics) analizi ile hesaplanan de g erlerle kar s i la s t i r i lm i s t i ...

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Heat Transfer Analysis of Thermal Barrier Coatings on a Metal Substrate

Thermal barrier coatings (TBCs) are used in order to protect hot section component parts from hig... more Thermal barrier coatings (TBCs) are used in order to protect hot section component parts from high temperature effect, extend the service life of the parts and reduce the maintenance costs in gas turbines. Thermal conductivity of TBCs directly affects the strength temperature of operating parts in hot section. The gas turbines' operating temperatures and efficiency change depending on thermal conductivity of TBCs. For this reason to determine the thermal conductivity of TBCs directly concern the turbine design. In this study, effective thermal conductivity layered structure which is composed of metal substrate and thermal barrier coating has been obtained numerically. Solutions have been performed taking conduction and radiation into consideration for different boundary conditions for TBC which have two different porosity. As a result of analyses, it has been determined that radiation boundary condition solution is 7% lower than the heat conduction solution.

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Mukayese metodu kullanılarak termal bariyer kaplamasının ısı iletim katsayısının deneysel olarak tayin edilmesi / Determining the thermal conductivity of thermal barrier coatings experimentally by comparative method

Termal Bariyer Kaplamalar (TBK) gaz turbinlerinin sicak kisim parcalarinda, malzemelerin yuksek s... more Termal Bariyer Kaplamalar (TBK) gaz turbinlerinin sicak kisim parcalarinda, malzemelerin yuksek sicaklik etkilerinden korunmasi ve gaz turbininin veriminin artirilmasi amaciyla yaygin olarak kullanilmaktadir. Teknolojik gelismelere paralel olarak gaz turbinlerinin calisma sicakliklari giderek artmakta, buna bagli olarak gaz turbinlerinde kullanilan TBK’larin isil ve mekanik dayanimlarinin artirilmasi gerekmektedir. Isi iletim katsayisi, TBK’larin isil dayanimlari acisindan en onemli faktorlerden biridir. Bu calismada, atmosferik plazma sprey yontemiyle gerceklestirilmis TBK’nin isi iletim katsayisi mukayese metodu kullanilarak deneysel olarak incelenmistir. Deneylerde uc farkli gozeneklilik oranina sahip TBK icin olcum yapilmistir.Referans malzemesi olarak 321 paslanmaz celik kullanilmis olup, referans malzemesinin sicakliga bagli isi iletim katsayisi ise Lazer-Flas olcum metodu ile elde edilmistir. Olcumler oda sicakligi ile 600 oC arasinda yapilmis, elde edilen sonuclar literatu...

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Numerical analysis of pulverized biomass combustion

E3S Web of Conferences, 2021

Combustion of pulverized biomass in a laboratory swirl burner is computationally investigated. Th... more Combustion of pulverized biomass in a laboratory swirl burner is computationally investigated. The two-phase flow is modelled by an Eulerian-Lagrangian approach. The particle size distribution and turbulent particle dispersion are considered. The radiative heat transfer is modelled by the P1 method. For modelling turbulence, different RANS modelling approaches are applied. The pyrolysis of the solid fuel is modelled by a single step mechanism. For the combustion of the volatiles a two-step reaction mechanism is applied. The gas-phase conversion rate is modelled by the Eddy Dissipation Model, combined with kinetics control. The results are compared with measurements.

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Katı yüzey ışınımı ile gaz yakıtlı ocaklarda ısı geçişinin arttırılması

Itudergisi D, Feb 5, 2011

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Benchmark study of 2D and 3D VOF simulations of a simplex nozzle using a hybrid RANS-LES approach

Fuel, 2022

Validation and comparison of 2D and 3D numerical simulations of flow in simplex nozzles

International Conference on Liquid Atomization and Spray Systems (ICLASS)

Numerical simulations of pressure swirl atomizers are computationally expensive due to transient ... more Numerical simulations of pressure swirl atomizers are computationally expensive due to transient and multiphase flow behavior. In this study, 2D and 3D VOF simulations are performed for a geomerty which has high swirl chamber length-to-diameter ratio of 1.33. discharge coefficient (CD) and spray angle values are compared to the experimental data. Moreover, a benchmark study is conducted between 2D and 3D methods in terms of accuracy, computational cost and flow variables such as orifice exit axial and tangential velocity. The simulations are performed using a hybrid RANS-LES approach, IDDES model. It is observed that 2D simulation has lower accuracy in the validation parameters such as discharge coefficient and spray angle as compared to the 3D simulation. The main reason for 2D simulation inaccuracy might be the tangential port inlet effects and wrong estimation of the loss of swirl inside the swirl chamber. On the other hand, 2D simulations have approximately 1000 times lower computational cost than 3D simulations.

format_quoteFor 3D simulations, grid sensitivity determined 6.57 million cells yielded consistent CD values of 0.331 across multiple grids.format_quote

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Simulation of biomass gasification in a BFBG using chemical equilibrium model and restricted chemical equilibrium method

Biomass and Bioenergy

Experimental results of underground coal gasification of Turkish lignite in an ex-situ reactor

Fuel

Testing, Product Certification, and Inspection of Photovoltaic Modules for Local Production

Springer Proceedings in Energy, 2017

Certification Issue of Solar Photovoltaic Modules for Local Production, Problems, and Solutions in Turkey

Progress in Clean Energy, Volume 2, 2015

ABSTRACT By Turkey&#39;s developing technology and growing economy, to meet the increasing en... more ABSTRACT By Turkey&#39;s developing technology and growing economy, to meet the increasing energy needs, Turkey should focus on domestic and renewable energy resources. Any growth in energy supply must be achieved in a low carbon way. In this process, the production of electricity from solar energy, namely photovoltaic technology, will have a large share. Hence determining the quality of photovoltaic modules has great importance both for financial terms and manufacturing. Determination of quality and reliable photovoltaic modules is only possible by the product certification and inspection services. Thus, the production stage of the module and installation process can be demonstrated by checking all of the quality system standards. In order to ensure the most accurate and independent service, internationally accreditation is crucial. There are three steps in front of Turkey during the adaptation of solar energy. First of them is quality production of photovoltaic modules, second is testing and certification, lastly proper installation of photovoltaic modules on to the power plants. This research finds solutions for the problems facing in testing and certification process of solar photovoltaic modules for local producers by local certification laboratories and certification body. As there are different elements which affect quality of photovoltaic modules, this research focuses on production of solar photovoltaic modules in Turkey, certification and accreditation for photovoltaic modules, regulations in Turkey, encountered problems and solutions.

Inspection criteria of PV module production facilities for certification bodies: Important step on the way of smart development

2015 3rd International Istanbul Smart Grid Congress and Fair (ICSG), 2015

As a part of smart development, while technology of producing PV module develops, the requirement... more As a part of smart development, while technology of producing PV module develops, the requirements for testing and certification of PV modules become more complicated and essential. Solar energy promises a high potential for Turkey as well as producing solar related products such as solar cells, PV modules and inverters which will enable a smart urbanization through smart grids. Certification of these products brings customer satisfaction and high product quality. In this paper, the importance of solar PV module certification and the factory inspection process is emphasized which plays a key role in smart development of cities. Critical points of factory inspection process are noted and new type of procedures are suggested for certification bodies responsible for the certification processes.

format_quoteTurkey has only one accredited certification body for solar PV modules, hindering local manufacturing quality assurance.format_quote

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Heat Transfer Analysis of Thermal Barrier Coatings on a Metal Substrate Metal Bi̇r Ana Malzeme Üzeri̇ndeki̇ Termal Bari̇yer Kaplamanin Isi Transfer Anali̇zi̇

Journal of Thermal Science and Technology

Thermal barrier coatings (TBCs) are used in order to protect hot section component parts from hig... more Thermal barrier coatings (TBCs) are used in order to protect hot section component parts from high temperature effect, extend the service life of the parts and reduce the maintenance costs in gas turbines. Thermal conductivity of TBCs directly affects the strength temperature of operating parts in hot section. The gas turbines' operating temperatures and efficiency change depending on thermal conductivity of TBCs. For this reason to determine the thermal conductivity of TBCs directly concern the turbine design. In this study, effective thermal conductivity layered structure which is composed of metal substrate and thermal barrier coating has been obtained numerically. Solutions have been performed taking conduction and radiation into consideration for different boundary conditions for TBC which have two different porosity. As a result of analyses, it has been determined that radiation boundary condition solution is 7% lower than the heat conduction solution.

format_quoteTBCs are crucial for increasing gas turbine efficiency by manipulating microstructural defects affecting heat transfer.format_quote

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Determining the thermal conductivity of thermal barrier coatings experimentally by comparative method (Turkish)

ABSTRACT

Heat Transfer Analyses of Thermal Barrier Coatings on a Metal Substrate

Thermal barrier coatings (TBCs) are used in order to protect hot section component parts from hig... more Thermal barrier coatings (TBCs) are used in order to protect hot section component parts from high temperature effect, extend the service life of the parts and reduce the maintenance costs in gas turbines. Thermal conductivity of TBCs directly affects the strength temperature of operating parts in hot section. The gas turbines' operating temperatures and efficiency change depending on thermal conductivity of TBCs. For this reason to determine the thermal conductivity of TBCs directly concern the turbine design. In this study, effective thermal conductivity layered structure which is composed of metal substrate and thermal barrier coating has been obtained numerically. Solutions have been performed taking conduction and radiation into consideration for different boundary conditions for TBC which have two different porosity. As a result of analyses, it has been determined that radiation boundary condition solution is 7% lower than the heat conduction solution.

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