DNS of a turbulent channel flow with pin fins array: parametric study

Gas turbines used in the aerospace industry are subject to extremely high temperatures from the combustor. Efficient cooling systems are required to avoid damage to the turbine blades and stators. There are two approaches mainly used in the cooling and protection of the turbine blades and stators, which are external and internal cooling. External cooling is achieved by jets in the exterior of the blade that creates a thin relative cold air film around the blade. The film prevents that the incoming hot air enters in direct contact with the turbine blade. Internal cooling is obtained by the use of internal channels with turbulators and pin fins exposed to a coolant fluid flow. At the trailing edge of the blade, pin fins are placed to increase the heat transfer while providing structural support to the blade itself (Metzger

et al.

,

1984

). Metzger

et al.

(

1984

) estimated that the pin heat transfer surface coefficients doubles the end-wall coefficients. They also showed how the orientation with respect to the mean flow affects the heat transfer and the pressure drop for pin fin arrays. On the other hand, Chyu

et al.

(

1999

) concluded that the heat transfer in the pin fins is 10 to 20 percent higher than the end-wall.