Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Exergetic Analysis of a Continuous Bi-Axially Oriented Polypropylene (bopp) Film Unit in a Plastic Processing Plant(Inderscience Enterprises Ltd., 2009) Balta, M. Tolga; Hepbaşlı, Arif; Hancıoğlu, Ebru; Özcanlı, Şevket Cihangir; Yılmazer, Ertan; Yurdakul, İbrahim; Dişbudak, ÖzgürThis paper deals with an exergy analysis of the stretching process of bi-axially oriented polypropylene films using a hot oil coiler along with stretching and crystallising unit. Exergy destructions and efficiencies in each of the system components are calculated, while the exergy loss and flow diagram (the so-called Grassmann diagram) is presented for the transverse direction (TD) unit. The so-called functional (on the product or benefit/fuel basis) and universal (on the output/input basis) exergy efficiency values of the TD unit are calculated to be 26.40% and 28.46% at a recommended exhaust air relative humidity of 0.0098 kg water/kg air, respectively.Article Citation - WoS: 138Citation - Scopus: 181An Experimental Study on Performance and Emission Characteristics of a Hydrogen Fuelled Spark Ignition Engine(Elsevier Ltd., 2007) Kahraman, Erol; Özcanlı, Şevket Cihangir; Özerdem, BarışIn the present paper, the performance and emission characteristics of a conventional four cylinder spark ignition (SI) engine operated on hydrogen and gasoline are investigated experimentally. The compressed hydrogen at 20 MPa has been introduced to the engine adopted to operate on gaseous hydrogen by external mixing. Two regulators have been used to drop the pressure first to 300 kPa, then to atmospheric pressure. The variations of torque, power, brake thermal efficiency, brake mean effective pressure, exhaust gas temperature, and emissions of NOx, CO, CO2, HC, and O2 versus engine speed are compared for a carbureted SI engine operating on gasoline and hydrogen. Energy analysis also has studied for comparison purpose. The test results have been demonstrated that power loss occurs at low speed hydrogen operation whereas high speed characteristics compete well with gasoline operation. Fast burning characteristics of hydrogen have permitted high speed engine operation. Less heat loss has occurred for hydrogen than gasoline. NOx emission of hydrogen fuelled engine is about 10 times lower than gasoline fuelled engine. Finally, both first and second law efficiencies have improved with hydrogen fuelled engine compared to gasoline engine. It has been proved that hydrogen is a very good candidate as an engine fuel. The obtained data are also very useful for operational changes needed to optimize the hydrogen fueled SI engine design.
