Abstract:
The cooling performance of a shaped hole is investigated experimentally using a two-dimensional turbine vane cascade. The test section is designed to match Mach numbers, Reynolds numbers, pressure distributions, passage mass flow rates, boundary layer development, streamline curvature, and physical dimensions of turbine airfoils in operating gas turbine engines for industrial power generation. The test section walls are made of acrylic for the optical measurements with inlet cross section area of 10 cm by 5.4 cm. One row of laid-back fan-shaped axially-oriented cooling holes is located on the pressure side. The main stream Reynolds number based on the axial chord is 1.4E5 and inlet Mach number is 0.16. The local distributions of the heat transfer coefficient and film cooling effectiveness is obtained using a transient Thermochromic Liquid Crystal (TLC) technique for four different blowing ratios. The effectiveness of the shaped holes increases by the increase of the blowing ratio with a slight reduction on the heat transfer enhancement. The nature of the flow interaction between jet and mainstream is clarified using Particle Image Velocimetry (PIV) to support the heat transfer findings.