Yazar "Korkmaz, Safa" seçeneğine göre listele

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    Conceptual Design and Analysis of a Cryogenic Hydrogen Fueled 100 kN Thrust Capacity Rocket with RPA Program
    (Kırıkkale Üniversitesi, 2022) Korkmaz, Safa; Yaman, Hayri
    In this study was made a conceptual design and analysis of thrust chamber of 100 kN rocket powered by cryogenic hydrogen. Cryogenic oxygen was used as oxidizer. It was determined as boundary conditions which the combustion chamber pressure is 20 MPa and the nozzle outlet pressure was determined 0.101325 MPa. The optimum rocket geometry was created using the RPA computer program within the boundary conditions. Three-dimensional rocket model was drawn with the SOLIDWORKS program. The analysis of the designed rocket was carried out using RPA and CEA programs. Changes of pressure, temperature and Mach number which is rocket internal ballistic parameters were investigated. According to the analysis outputs, the combustion chamber temperature was 3290.9 K and the nozzle exit temperature 1310 K. The nozzle outlet pressure obtained from the RPA and CEA programs was provided as 0.1013 MPa under sea level conditions as desired.
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    Developments in the RCCI engines powered by several alternative fuel types: An overview
    (Sage Publications Ltd, 2024) Korkmaz, Safa; Yaman, Hayri; Yesilyurt, Murat Kadir
    The perspective on internal combustion engines (ICEs) has changed because of the step-by-step decrease in oil reserves, environmental concerns, and many other reasons. However, the use of these engines will continue in the coming years. The development of ICEs has accelerated in recent years. As a result, studies on systems that can improve performance and reduce pollution in engines are carried out by many researchers. The basis of the studies carried out in this context is the change in the combustion mode. In other words, the emergence of different combustion modes is given importance by researchers. Among these, many studies have been made on the implementation of the reactivity-controlled compression ignition (RCCI) combustion mode. RCCI engine uses two different fuels. These fuels are low-reactivity (alcohol, gasoline, etc.) and high-reactivity (diesel, biodiesel, etc.) fuels. In addition, the fact that different alternative fuel types can be employed in these engines has made them popular all over the world. This review presents the results of the effects of parameters such as fuel ratio, different injection strategies, exhaust gas recirculation (EGR) rate, compression ratio, and piston geometry on the performance, emissions, and combustion behavior of RCCI engines using both conventional and alternative fuels. This study has been compiled to provide an overview of the current status of the RCCI concept and to offer benefits to researchers.
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    Öğe
    Regenerative Cooling Analysis of Rocket Engine Operated by Liquid Hydrogen and Liquid Oxygen
    (Kırıkkale Üniversitesi, 2021) Korkmaz, Safa; Yaman, Hayri
    Liquid fueled rocket engines have to be cooled due to their long-term operation at high combustion temperatures. Cooling system design is one of the most important issues in liquid fueled rocket engines since rocket engines are exposed to 2500-3500 K temperature during operation and this temperature range is above the melting temperature of most metals. Different cooling techniques are applied for the safe and stable operation of liquid fueled rocket engines. Generally, regenerative cooling method is used in liquid fueled rockets. In this study, the regenerative coaxial cooling system was designed for rocket engine which produces 100 kN thrust with liquid oxygen and liquid hydrogen. The parts of the rocket exposed to high temperatures were coated with zirconium oxide (ZrO2). Numerical analysis of rocket was carried out through the RPA program by dividing into seven zones. It was observed that liquid hydrogen entering the cooling channel at 23.75 MPa pressure and 45 K temperature provides stable cooling conditions with the output of 23.095 MPa and 141.21 K temperature.
  • Küçük Resim
    Öğe
    Sıvı yakıtlı roket motor tasarımı ve performans karakteristiklerinin teorik araştırılması
    (Kırıkkale Üniversitesi, 2019) Korkmaz, Safa; Yaman, Hayri
    Sunulan tez çalışması ile gerçek bir roket tasarımının ana temelini oluşturan teorik tasarım ve analiz çalışması yapılmıştır. Roket tasarım parametrelerinden olan yakıt kombinasyonu, karışım oranı, yanma odası basıncı ve nozul çıkış basıncı sınır şartları olarak belirlenmiştir. Sıvı yakıtlı roket tasarımının temel unsurları oluşturan yanma odası, nozul, enjektör ve soğutma sistemi tasarlanmıştır. Bu tasarımda sıvı yakıtlı roket itki kapasitesi 100 kN olarak belirlenmiştir. Roket tasarımı önce analitik olarak yapılmıştır. Analitik olarak belirlenen roket geometrisi RPA programı ile optimize edilmiştir. CEA programı ile RPA programının analiz sonuçlarının doğruluğu incelenmiştir. Roketin üç boyutlu modeli SOLİDWORKS bilgisayar programında oluşturulmuştur. Roket CFD analizi SOLİDWORKS programında oluşturulan üç boyutlu modeli kullanılarak ANSYS FLUENT programında gerçekleştirilmiştir. Bütün analiz sonuçları karşılaştırılmıştır. Hedeflenen roket tasarımı analitik ve simülasyon analizleri ile imalat öncesi farklı programlarda alınan sonuçlar ile karşılaştırılarak doğruluk teyidi yapılmıştır. Roket itki odası malzemesi seçilmiştir.