Influence of different shoulder widths on film cooling characteristics on GE-E3 blade tip

Three-dimensional simulations of squealer tip on GE-E3 blade with eight film cooling holes were numerically studied. Numerical simulations were performed to predict the leakage flow and the tip heat transfer in the tip-gap region with the κ-ε model. For the squealer tip, the depth of the cavity is 2.42 mm, and the width of the shoulder is 0.77 mm, which forms a narrow rim and a wide cavity, decreasing the coolant momentum and the tip leakage flow velocity. The cavity contributes to the improvement of the cooling effect. In view of the absence of detailed three-dimensional flow measurements in the tip region of the blade and current lack of related literatures, it is necessary to fix attention on the shoulder width. To investigate the leakage flow influenced by the rim width, the paper used the asymmetric structure. The rim width in pressure surface in the tip-gap region is different from the one in suction surface. Numerical simulations were made at three different models, which were 0.77 mm, 1.22 mm and 1.67 mm respectively on the pressure side rim, and which were 0.77 mm, 2.27 mm and 3.77 mm respectively on the suction side rim. The rim width has a significant influence on local tip heat transfer coefficient distribution and the tip leakage flow. The detailed information was obtained under global blowing ratios of M=0.5, 1.0 and 1.5. In addition, varying rim width models of squealer tip without film cooling holes were compared with those with film cooling holes.