Numerical investigations of pulsed film cooling on an entire turbine vane

This paper presents a numerical investigation of pulsed film cooling on a modified NASA C3X vane, which has five rows of film cooling hole: three rows at leading edge, and the other two at pressure side and suction side, respectively. Square and sinusoidal waves are considered to pulse cooling air injection. The performances of film cooling effectiveness are discussed at three blowing ratios (0.5, 0.75 and 1.0) and four Strouhal numbers (0.0027, 0.0054, 0.0108 and 0.0216). Previous investigations of pulsed film cooling were limited within flat plates or semicircular cylinders, therefore it is necessary to provide a comprehensive reference regarding pulsed film cooling on an entire turbine vane. Through the present numerical simulations conducted on the entire turbine vane, the following interesting phenomena are discovered: 1) at leading edge and pressure side, film cooling effectiveness decreases when blowing ratio or Strouhal number increases, but at suction side, the trend reverses; 2) sinusoidal wave pulsed flow leads to less mainstream ingestion into film hole than square wave pulsed flow; 3) in the leading edge region, sinusoidal wave pulsed flow exhibits higher film cooling effectiveness than steady flow at blowing ratios of 0.75 and 1.0.