Introduction of a Parameter Based Compressor Blade Model for Considering Measured Geometry Uncertainties in Numerical Simulation

Abstract

This paper provides a method to transfer geometric uncertainties of compressor blades into the numerical simulation. Therefore a method to capture geometric variations of measured blades by typical profile parameters is introduced. An optical measurement technique using structured light is applied to scan compressor blades in order to receive a three–dimensional point cloud of the measured blade. The evaluation of these points is done on curves of constant spanwise coordinate between hub and casing. In this way, section outlines are extracted, which then are split into camber lines and chord lines. The derived thickness and camber distributions are used to specify typical profile parameters for each section. To consider the geometric uncertainties in numerical simulation, the design geometry is adapted through a special reconstruction algorithm. Therefore the differences between the measured airfoil and the design geometry are quantified by the profile parameters. Since only the difference is analyzed, few parameters are needed to model the measured geometry. The three-dimensional blade then is reconstructed through assignment of the parameters to the spanwise coordinate. To illustrate the developed method, the whole process chain is applied on a selected compressor blade.