Wind energy has been seen as one of the most suitable sources of renewable energy. Wind energy is low cost when compared the other sources. Therefore, wind energy can gain an edge over the fossil-fired power plants. Aerodynamic efficiency of the airfoil is very crucial for aerodynamic efficiency of the wind turbine. The primary purpose of our study was to analyze the NACA0012 and NACA4412 airfoil at various attack angles with constant Reynolds number and to examine the effects of the symmetrical and asymmetrical profiles of the airfoil. Analysis of aerodynamic performance of NACA0012 and NACA4412 airfoil were performed with using ANSYS Fluent program. Also, lift coefficients and drag coefficients were calculated at various attack angles. According to calculations, optimum attack angles were found for each profile. Finally, NACA0012 and NACA4412 airfoils were discussed and reported in terms of their airfoil performances.

Homogenous charge compression ignition (HCCI) cases are compared for improvements on the combustion chamber design of the engine to achieve near zero particulate matter (PM) and NOx emissions. Therefore combustion simulations of the engine have been performed to find out emission generation in the cylinder. The interaction of air motion with high-pressure fuel spray has also been analysed. Finally, a comparison has been made considering the performance of the engine for various configurations such as compression ratio, injection timing, and cone angle. The results are widely in agreement qualitatively with the previous similar experimental and computational studies in the literature.

The aim of this study is to find out the optimum operating conditions in a diesel engine fueled with compressed biogas (CBG) and pilot diesel dual-fuel. One-dimensional (1D) and three-dimensional (3D) computational fluid dynamics (CFD) code and multiobjective optimization code were employed to investigate the influence of CBG-diesel dual-fuel combustion performance and exhaust emissions on a diesel engine. In this paper, 1D engine code and multiobjective optimization code were coupled and evaluated about 15000 cases to define the proper boundary conditions. In addition, selected single diesel fuel (dodecane) and dual-fuel (CBG-diesel) combustion modes were modeled to compare the engine performances and exhaust emission characteristics by using CFD code under various operating conditions. In optimization study, start of pilot diesel fuel injection, CBG-diesel flow rate, and engine speed were optimized and selected cases were compared using CFD code. CBG and diesel fuels were defined as leading reactants using user defined code. The results showed that significantly lower NOx emissions were emitted under dual-fuel operation for all cases compared to single-fuel mode at all engine load conditions.