Sürdürülebilir Kalkınma Amaçları
Yazarlar
Yayınlar
- MakaleYalnız künye2017Scopus SJRQ1Determination of optimum ejector operating pressures for anodic recirculation in SOFC systems
Genc, Omer; Toros, Serkan; Timurkutluk, Bora
In this study, a numerical analysis of an ejector for micro combined heat and power system based on 18 kW Solid Oxide Fuel Cell (SOFC) using methane as fuel is presented. An ejector design, which reflects the real system conditions in the view of the flow characteristics, is provided and the ejector performance is numerically investigated for various methane pressure to exhaust pressure ratios and methane inlet temperatures. The results show that the fuel inlet temperature and the pressure ratio of the methane to exhaust significantly affect the steam to carbon ratio (STCR) and entrainment ratio. The higher pressure ratio and methane temperature allow a high entrainment ratio and STCR, but as pressure ratio and methane temperature increase, STCR and entrainment ratio remain unchanged after a specific value. 1140 different scenarios related with the inlet and outlet pressures of the ejector and methane temperature are created to determine the optimum operating conditions. The simulations show that the optimum methane inlet pressure is 7 bar and exhaust pressure is 1.159 bar for the ejector geometry of the interest. The entrainment ratio and STCR are determined as 2.05 and 0.92, respectively at this optimum scenario.
AtıfScopus34WoS31OpenAlex37
İncele - MakaleAçık Erişim2015Scopus SJRQ2A comparison of support systems obtained from the RMR89 and RMR14 by numerical analyses: Macka Tunnel project, NE Turkey
Kanik, Mustafa; Gurocak, Zulfu; Alemdag, Selcuk
The aim of this study is to highlight the importance of the numerical approach in realistic support design for tunneling. The Macka Tunnel, which is planned to be constructed between the Trabzon-Gumushane highways, located in the Northeastern Turkey, was selected for a field study. The lithology of the study area consists of Late Cretaceous-aged sedimentary rocks, known as the Catak and Esiroglu formations, and the Late Cretaceous-aged Kackar Rhyodacite. In order to determine the geotechnical properties of rock masses and intact rocks, field and laboratory studies were carried out.The rock masses were classified in terms of the Rock Mass Rating (RMR) using the versions of RMR89 and RMR14 and then the preliminary support systems for the tunnel were determined, accordingly. The support systems obtained from the RMR versions were analyzed using the finite element method (FEM). The maximum total displacement and the maximum thickness of plastic zone occurred around the Macka Tunnel after installation the support systems suggested by the RMR89 and RMR14 versions were compared to determine which the RMR version suggests more realistic support system. The results showed that the support systems obtained from the RMR14 version suggests more realistic support element for fair rock masses and great horizontal stress values.
AtıfScopus29WoS27İncele