Probabilistic CFD Analysis of High Pressure Turbine Blades Considering Real Geometric Effects

Abstract

This paper addresses the consideration of variability due to manufacturing and abrasion of high pressure turbine (HPT) blades through probabilistic CFD investigations. Currently, the influences of those effects onto relevant aerodynamic quantities are covered by safety factors and conservative assumptions. The probabilistic investigation on the other hand, based on realistic input parameters, will enable designers to possibly reduce safety factors and provide the foundation for more robust blade designs. In order to establish a sound statistical database, 500 new and used HPT blades were digitised with an optical 3D scanning system in order to record the outer geometric variability. As described in the work of Heinze et al. [1], the measured point clouds are parameterized using classical profile parameters and a process to rebuild various blade geometries has been developed. In terms of probabilistic investigations, in our case by applying sampling-based methods, a large number of 3D CFD simulations for a 1.5 HPT stage have been conducted using probabilistic blade geometries, followed by a sensitivity analysis and a detailed investigation of the probabilistic system behaviour. For visualization of possible correlations, the technique of Statistics on Passage (SoP) was chosen, as described in [2].