Investigation of Film Cooling Effectiveness on Squealer Tip of a Gas Turbine Blade

Abstract

The effect of the film cooling holes arrangements and the blowing ratio on the tip film cooling effectiveness in a rotating blade with the squealer tip was investigated by using numerical methods in this paper. The first stage rotor blade with squealer tip of GE-E3 engine high pressure turbine was adopted to perform this study. The tip clearance was specified as 1% of the blade height, and the groove depth was specified as 2% of the blade height. The different turbulence models were checked by Kim’s experiment data [1] in 1995, and the standard k-ε turbulence model was chosen to predict the film cooling effectiveness on the blade tip. The film holes were arranged at the tip camber line, the tip division line, the tip pressure side and the pressure surface near tip, respectively. The effect of the holes position on the tip film cooling effectiveness in the rotating blade was studied. The effect of the blowing ratio was analyzed for the cases that the film holes were placed at the tip division line and the pressure surface near tip. The results show that the area-averaged tip film cooling effectiveness reaches the highest when the film holes are placed along the tip division line, and the tip leakage mass flow rate can be reduced by placing the film holes on the pressure surface near tip.