Sivil Havacılık Araştırma ve Uygulama Merkezihttps://hdl.handle.net/11421/219972024-03-29T13:03:55Z2024-03-29T13:03:55ZSustainability assessment in piston-prop helicopter engineYıldırım, E.Altuntaş, ÖnderHikmet, Karakoç, T.Mahir, Nevinhttps://hdl.handle.net/11421/221492020-08-15T21:47:45Z2016-01-01T00:00:00ZSustainability assessment in piston-prop helicopter engine
Yıldırım, E.; Altuntaş, Önder; Hikmet, Karakoç, T.; Mahir, Nevin
About 75% of the world’s energy requirement is provided by fossil fuels, and there are various improvement efforts in all fields to ensure the effective use of available sources, taking into consideration the gradual decrease in fossil fuels. Several approaches are used against the decrease in energy sources including the concept of sustainability. Sustainability refers to the careful use of available sources by making advance plans to ensure that natural sources are not exhausted and are used in moderation so that the future generations can benefit from these sources. This study includes a sustainability assessment based on energy analyses for different engine power values varying between 150 and 600 SHP (Shaft Horse Power) in a spark-ignited, unsupercharged and air-cooled piston-prop helicopter engine. As a result of calculations, the highest exergetic sustainability index was found to be 0.15, and the lowest environmental impact factor value was found to be 6.86 at a power of 250 SHP. The lowest waste exergy ratio and the lowest exergy destruction factor were calculated to be 87.28and 66.77%, respectively. The power with the highest energy and exergy efficiency provided the highest exergetic sustainability index and thus the lowest waste exergy ratio, the lowest exergy destruction factor and the lowest environmental impact factor
2016-01-01T00:00:00ZExergetic and Energetic Response Surfaces for Small Turbojet EngineTuran, ÖnderKarakoç, Tahir Hikmethttps://hdl.handle.net/11421/221452020-08-15T21:47:37Z2012-01-01T00:00:00ZExergetic and Energetic Response Surfaces for Small Turbojet Engine
Turan, Önder; Karakoç, Tahir Hikmet
Fan, W
Exergy analysis permits meaningful efficiencies to be evaluated for a system or process, and the sources, causes and locations of thermodynamic losses to be determined. This study presents exergetic modeling of a small turbojet engine via exergetic response surfaces. Turbojet engine consists of an inlet, a centrifugal compressor, reverse flow combustion chamber, axial-flow turbine and exhaust nozzle. The flight Mach number and altitude are examined on the exergetic efficiencies of total engine performance. The results of analysis are given as three dimensional exergetic response surface plots related to these operating parameters.
2nd International Conference on Mechnaical and Aerospace Engineering (ICMAE 2011) -- JUL 29-31, 2011 -- Bangkok, THAILAND; WOS: 000303370300158
2012-01-01T00:00:00ZFlame-retardant effects of cyclic phosphonate with HALS and fumed silica in polypropyleneÜreyen, Mustafa ErdemKaynak, ElifYüksel, Gamzehttps://hdl.handle.net/11421/221472020-08-15T21:47:53Z2019-01-01T00:00:00ZFlame-retardant effects of cyclic phosphonate with HALS and fumed silica in polypropylene
Üreyen, Mustafa Erdem; Kaynak, Elif; Yüksel, Gamze
In this study, an N-alkoxy-hindered amine-based UV stabilizing agent (NOR-116) and nanosized silica particles (Aerosil R-972) were combined with a cyclic phosphonate based-flame retardant (FR; PCO-900) and incorporated into polypropylene via melt extrusion in a microcompounder. In order to stimulate the conditions in the favor of further processing such as fiber spinning, the content of additives in polypropylene was kept low (up to 6.5 wt %). The effects of the PCO-900, alone and in combination with NOR-116 and Aerosil-R972, on the flammability and thermal stability of polypropylene were evaluated by limit oxygen index (LOI) tests, cone calorimetry, and thermogravimetric analysis. The proposed system with 3.5 wt % PCO-900/1.5 wt % NOR-116/1 wt % Aerosil-R972 decreased the heat release, increased the LOI and thermo-oxidative stability, and, thus, improved the fire resistance of polypropylene. The possible mode of FR activity was also discussed based on the analysis
WOS: 000478980600001
2019-01-01T00:00:00ZExergetic Destruction Effects Of Operating Conditions On The Turbojet Engine ComponentsKarakoç, Tahir HikmetTuran, Önderhttps://hdl.handle.net/11421/221442020-08-15T21:47:34Z2012-01-01T00:00:00ZExergetic Destruction Effects Of Operating Conditions On The Turbojet Engine Components
Karakoç, Tahir Hikmet; Turan, Önder
Fan, W
The minimization of exergy destruction brings the design as closely as permissible to the theoretical limit. This study presents exergy destruction analysis of a turbojet engine for different flight Mach number and altitudes. Turbojet engine being considered consists of an inlet, a centrifugal compressor, reverse flow combustion chamber, axial-flow turbine and exhaust nozzle. The flight Mach number and altitude are examined on the exergetic destructions of compressor, combustion chamber, turbine and exhaust nozzle. The results of component-based destruction analysis are given as three dimensional exergetic-destruction response surface plots related to altitude and flight Mach number.
2nd International Conference on Mechnaical and Aerospace Engineering (ICMAE 2011) -- JUL 29-31, 2011 -- Bangkok, THAILAND; WOS: 000303370301128
2012-01-01T00:00:00Z