The objective of this study is to investigate the aerodynamics characteristic of airfoil NACA 4412 based on experiment and numerical simulation. A 3D airfoil with chord length (C) of 100 mm and span-width (S) of 200 mm was fabricated in order to be tested by subsonic wind tunnel at inlet air velocity of 10 m/s, whereas numerical study was realised by 2D airfoil reffering to geometrics in the experiment. The structured mesh with 810,000 elements number was constructed by Gambit meshing tools up to reach the near wall resolution of Δy+ = 17.2. Spallart-Almaras turbulence model was applied in the simulation of RANS study.The effect of various angle of attack (α) between -5 and 20 was investigated for both methods in terms of the aerodinamic characteristics such as lift coefficient (CL), drag coefficient (CD), and lift-drag ratio (L/D). The pressure coefficient (CP) and flow visualisations around the airfoil were generated by simulation method. In general, the results show that the data resulted by both methods agree well compared to the other studies, mainly for the lift and drag coefficients. Both coefficients increase with rising the angle of attack before approaching a stall condition at α = 15 o . From this point, lift coefficient drops significantly due to large turbulent wake that reduces to lift and influence to drag. The change of attack angles influences the shifting of both stagnation and expansion points in the leading edge, furthermore it causes the overall aerodynamic characteristics. The increase of pressure difference between upper and lower surfaces of airfoil body causes the rise of lift.

A condenser is one of the main equipment in a Combined Cycle Power Plant (CCPP) cooling system which has a great influence on steam turbine output and thermal efficiency of the whole power plant as well. The objective of this study is to analyze the effect of increase in condenser pressures on the heat rate and electricity production costs. The primary data is acquired from the DCS. These data are then compared to those of the best performance operating data. The differences of these two data of 23 parameters, are then integrated with the impact factor to gain the heat rate loss. Based on the heat rate loss, then the cost of electricity production is established accordingly. The study concludes that the increase of condenser pressure from 2.41 inHgA to 2.82 inHgA results in increase of plant heat rate 19.55 kcal/kWh. The 5 great parameters to contribute to this loss are: HP and LP steam flows, condenser pressure, stack temperatures of HRSG 1.3 and 1.2. Meanwhile, the cost of production rises up from 751 IDR/kWh to 805 IDR/kWh.