Kalkan, Orhan

Turbofan engines are one of the most common types of engines used in modern commercial and military aircraft due to their efficiency and performance characteristics. In this study, a thermodynamic model is generated using GasTurb 14 software for a commercial two-spool, unmixed flow, and booster turbofan engine (CFM56-5A3) used in Boeing A320-212. Besides, an exergy analysis of the modeled turbofan engine is performed. Exergy performance criteria such as exergy efficiency, exergy development potential, exergy destruction ratio, productivity lack ratio, and fuel depletion ratio are evaluated for the engine components. In addition, how bypass ratio (BPR) affects net thrust and specific fuel consumption (SFC) for the modeled turbofan engine is investigated. As a result, the net thrust and SFC values of the modeled engine and the actual engine are overlapped with 14.0% and 7.2% deviation, respectively. The maximum exergy efficiency occurs at the high-pressure turbine as 0.992. When the bypass ratio is minimum, the maximum net thrust and SFC occur as 62.24 kN and 24.08 g kN(-1) s(-1) , respectively. High pressure turbine has the minimum exergy development potential of 1528.5 kW.

Uzun, Sinem; Genç, Yasin; Acir, Adem

In this study, calcium carbonate (CaCO3) 3 ) was considered as nanoparticle. In the first part of the study, half-value layer (HVL) and mean free path (MFP) values, which are radiation shielding parameters, were investigated in determined energy ranges by Phy-X open access software. At increasing energy levels, the HVL value reached approximately 10 cm, while the MFP value reached approximately 17 cm. In the second part of the study, the reactor core geometry was modeled with the MCNP code and then the relative power distribution values were determined. COBRA code input was prepared with the determined relative power distribution values and thermal analyzes were made. These analyzes were performed for three different nanoparticle ratios. As a result of the analysis, the temperature value at the end of the channel was 613 K when only water was used as a coolant, while the temperature value at the end of the channel was 611.19 K when 0.03% nanoparticles were used. Although the coolant temperature increased with the nanoparticle ratio, it was observed that the temperature decreased when only water was used.

Kaba, Muhammet Yasin; Kurnuc Seyhan, Aslihan; Celen, Pinar; Celen, Ali

Solar collectors are frequently used in domestic water heating applications. In the design stage, the positioning of solar collector with suitable title angle is important in order to utilize from sun energy efficiently. In this study, the effect of tilt angle of a solar collector located to Erzincan city on monthly/daily average radiation values, water outlet temperature, energy and exergy efficiencies are theoretically investigated. It is seen that the maximum and minimum values of optimum tilt angles are 63 degrees ve 0 degrees for December and June, respectively. Tilt angles which are suggested for Erzincan (27.14 degrees) and calculated are compared for daily average hourly radiation values and it is seen that the maximum variation is 26% for January. In addition, energy and exergy efficiencies of solar collector are estimated and the maximum efficiencies are determined as 74.2% ve 9.7% for optimum tilt angles.

Celen, Ali; Kaba, Muhammet Yasin; Kalkan, Orhan

Nowadays, electric vehicles come to the fore more than vehicles with internal combustion engines since electric vehicles are environmentally friendly and highly more efficient. Selection and thermal management of the battery, which is one of the most important equipment that constitutes electric vehicles, is important. In this study, the general view (history, classification, sales numbers, market shares) of electric vehicles, battery types that can be used in electric vehicles and battery thermal management systems were investigated. Different types of batteries commonly used in applications are compared according to their characteristics, and among these batteries, it has been observed that the type of battery that can be used in electric vehicles is lithium-ion batteries which have high specific energy (118-250 Wh/kg), high energy density (200-400 Wh/L), high specific power (200-430 W/kg), high cycle life (2000) and ideal operating temperature (-20oC-60oC). The thermal management systems, which can be used to obtain maximum performance from these batteries, are investigated and advantages and disadvantages of these methods are investigated. While it has been seen that air cooling is sufficient in vehicles with low thermal load (hybrid electric vehicles, etc.), it is observed that the use of liquid and hybrid cooling methods is appropriate in vehicles with high thermal load (full electric vehicles).