Journal of Naval Sciences and Engineering

93-116

Authors: Salih Korhan ZORLU, Egemen SULUKAN

Ships embodying a wide range of energy carrier conversion, end-use technologies and emissions, can be considered as a whole energy system and require focused analysis to provide guidance and foresight for naval engineers, ship operators and fleet managers. Considering the emerging technologies in marine industry and the new regulations promulgated by the local or worldwide authorities, benefiting the superpowers of computing technologies became vital in order to let the stakeholders keep their profits up while fulfilling the regulations and restrictions. Since optimizing a system is the focus of all kinds of engineering, software tools aiming to provide guidance for the decision makers have been widely used for the last decades. This study anticipates to bring a comprehensive and open ended software tool solution for the stakeholders and the researchers of the shipping industry and to be the first step for a sophisticated open source software tool which will shape with the help of future researchers.

143-170

Authors: Fatih YILMAZ, Egemen SULUKAN

Today, approximately 85% of world trade is carried out by sea and ships are indispensable elements of transportation, logistics and trade. But on the other hand, approximately 2.5% of global green gas emissions, which have adverse effects on air quality and public health, is originated from ships and maritime transportation activities. Considering this situation, the International Maritime Organization promotes the use of renewable/alternative energy sources on ships, rather than fossil fuels. In the 11st Development Plan of Republic of Turkey, it is also aimed to convert the ships used for vehicle and passenger transportation in a short distance into “all-electric” concept. In this study, energy system analysis and modelling of a new generation ferry with a diesel electric propulsion system, which is used for vehicle and passenger transportation, have been carried out by using the Reference Energy System approach and Long- range Energy Alternatives Planning System software. In conclusion of the study, results of analysis related to the ferry’s energy system, which also include theoretical emission estimates for conversion scenario of the ferry’s energy system into hybrid concept, have been presented. Additionally, some suggestions for increasing energy efficiency of the ferry have been presented as well.

193-216

Authors: Uğur Buğra ÇELEBİ

Naval vessels are exposed to many of the rules and regulations determined by international treaties, there are few studies on life cycle analysis of these ships. The aim of study is to calculate life cycle impacts and cost analysis of two vital parts of a generic warship and investigate the emission reduction by using Life Cycle Assessment (LCA). Two important parts (valve and lubricating oil) of a generic warship are selected and the wastes and emissions of these parts are calculated by using licensed SimaPro software. The whole life cycle of the valve and lubricating oil is considered including transportation and recycling phases. Besides, Life Cycle Cost (LCC) analysis is implemented to the samples to calculate the benefits obtained by using LCA method. LCC is implemented on the system and its resulting total benefits, which is obtained by recycling process, is approximately 46,400 €. The environmental impacts of waste valve and lubricating oil are calculated by the help of licensed SimaPro software. The results show that recycling waste oil recovers the cost of waste oil separator by 30 % per ship.

1-24

Authors: Dr. Öğr. Üyesi Doğuş ÖZKAN, Kadir BÜYÜKHAMURKAR

Turbofan engines are used to provide thrust force by using the high temperature and pressure gases flow from the nozzle to move passenger planes or war jet planes. Turbofan engines consist of complicated parts such as axial fan, compressor, combustion chamber, turbine, which are manufactured with high engineering knowledge. Therefore, it needs to be well designed, analyzed and manufactured. In this study, an axial compressor of a warplane turbofan engine was designed and analyzed with AxStream software. Results were compared with real turbofan engine measured values, furthermore, computed flued dynamic and strain analysis were performed to evaluate compressor design parameters. Results showed that the polyprotic efficiency of the designed compressor was 2 % higher than the actual compressor. Furthermore, similar pressure and temperature were obtained at the outlet of the designed compressor.

45-70

Authors: Arş. Gör. Seda ATAŞ BAKDEMİR, Dr. Öğr. Üyesi Doğuş ÖZKAN, Dr. M. Cenk TÜRKÜZ, Dr. Öğr. Üyesi Elif UZUN, Prof. Dr. Serdar SALMAN

Gas nitriding is a widely applied thermochemical surface treatment, which is applied to enhance mechanical properties and wear characteristics of iron and steels. The impact of the gas nitriding process on the mechanical and wear resistance characteristic of DIN 1.2344 (X40CrMoV5-1) hot work steel were investigated in this paper. Nitrided and non-nitrided samples were characterized through a different method such as the optical microscope, scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, atomic force microscope (AFM) and 3D optical profilometer. The results of analyses reveal that increases in wear resistance of the nitrided sample due to the formation of surface layers of nitrides and oxides.