Suction and Pressure Side Film Cooling Influence on Vane Aero Performance in a Transonic Annular Cascade

Abstract

An experimental study on a film cooled nozzle guide vane has been conducted in a transonic annular sector to observe the influence of suction and pressure side film cooling on aerodynamic performance. The investigated vane is a typical high pressure gas turbine vane, geometrically similar to a real engine component, operated at an exit reference Mach number of 0.89. The aerodynamic results using a five hole miniature probe are quantified and compared with the baseline case which is uncooled. Results lead to a conclusion that the aerodynamic loss is influenced substantially with the change of the cooling flow rate regardless the positions of the cooling rows. The aerodynamic loss is very sensitive to the blowing ratio and a value of blowing ratio higher than one leads to a considerable higher loss penalty. The suction side film cooling has larger influence on the aerodynamic loss compared to the pressure side film cooling. Pitch-averaged exit flow angles around midspan remain unaffected at moderate blowing ratio. The secondary loss decreases (greater decrease in the tip region compared to the hub region) with inserting cooling air for all cases compared to the uncooled case.

Improvement of Flat-Plate Film Cooling Performance by Double Flow Control Devices: Part I — Investigations on Capability of a Base-Type Device

“…Interestingly, the air ejection with higher blowing ratio tended to reduce the total pressure loss especially for RH cases, regardless of the existence of the device. Similar findings were reported by Saha et al [14].…”

Numerical Investigation on Aerodynamic Performances of the Single-Stage Transonic Turbine With Various Coolant Ejection Positions and Coolant Mass Flow Rates

“…They found that the aerodynamic losses varied with the cold airflow regardless of the position of the air film holes; moreover, the suction side cooling was more sensitive than the PS cooling to aerodynamic losses caused by the variation of blow ratio. Alameldin et al (2014) proposed a simplified method of directly introducing the coolant into the vane surface as a boundary condition, and the computational results were in great agreement with the experimental results of Saha et al (2013). To analyze the film cooling and shock wave interaction, an uncertainty quantification methodology was presented by Carnevale et al (2014), regarding the variability of geometrical parameters as uniform probability distributions.…”

“…Furthermore, the optimization of the film cooling hole arrangement had been realized using the CFD code. Saha et al (2013) surveyed a transonic film-cooled NGV with all the cooling air ejections placed on the front part of it before the throat. They found that the aerodynamic losses varied with the cold airflow regardless of the position of the air film holes; moreover, the suction side cooling was more sensitive than the PS cooling to aerodynamic losses caused by the variation of blow ratio.…”