Cooling Efficiency of a NACA4412 airfoil: Numerical application

Abstract

The temperatures imposed on the blades of the first stages of turbines are generally very high; these expose the latter to harmful thermal effects, pushing manufacturers to continually improve techniques for cooling the blades. It is true that by increasing the temperature of the gases at the inlet of the turbines, we increase the efficiency, the performance of the machines, and we improve the power and fuel consumption with a significant reduction in polluting gases. Thus, the current general trend among manufacturers is to design machines that operate at increasingly high inlet temperatures. This has led, therefore, to the constant search for new materials with high thermal resistance and to constantly improve cooling techniques. This task is conditioned by a good and deep understanding of the phenomenon of heat transfer in turbine blades. This study examines the three dimension numerical simulation of the flow and heat exchange inside an internal cooling channel of a gas turbine blade with the profile of NACA 4412. This channel plays an important role in increasing heat exchange between the cooling air and the walls of the blade. In the turbulent regime, we have investigated the cooling of a profile blade NACA 4412 using forced convection (V = 200, 250, 300, 350, and 400 m / s). determined that the value of the cold air's speed increases with the intensity of the secondary flow inside the morning. Results found that, The flow dynamics and kinematics of fluid particles alter significantly when the cooling air speed is increased, and the cooling level is enhanced.