Flow Field Measurements in a Cold Flow Annular Sector Turbine Cascade Test Facility and an Annular Sector Cascade Test Facility Operating at Near-Engine Conditions

Abstract

Aerodynamic investigations in a cold flow annular sector high-pressure turbine cascade test facility and an annular sector cascade facility operating at near-engine conditions are presented. The test section of both facilities is a 36° sector cascade of a modern turbine stator consisting of 6 vanes. The two facilities have been designed in order to gain detailed information concerning film cooled gas turbine vanes. Due to the operation conditions of the hot annular sector cascade it takes over the part of detailed investigations of the influence of film cooling on the heat transfer. In the cold annular sector cascade facility investigations on the aerodynamic behavior of the cascade are performed. Both facilities together will lead to a better understanding of the complicate three-dimensional flow in modern gas turbines. A detailed description of both facilities is given in this paper. Aerodynamic investigations in both facilities were performed. The in- and outlet Mach number and profile Mach number distribution is in good agreement in both of them and shows a periodic flow filed. Aerodynamic performance measurements in the cold flow facility have been conducted by means of a five-hole pneumatic pressure probe traverses 106% of cax downstream of the cascade to gain information about the quality of the flow field across flow passages “+1” and “–1” in terms of yaw angle, pitch angle and primary loss distribution. Comparison with a three dimensional Navier Stokes solvers show a very good agreement with the measurements. In order to deduce the external heat transfer coefficient on the vane a transient test procedure was adopted in the high-pressure hot facility. The dependency of the heat transfer coefficients on the Reynolds number is presented in the paper. The experimental results show reasonable agreement with calculations using a two dimensional boundary layer code.