Inspection of assembly error with effect on throat and incidence for turbine blades

Turbine blades are the key aerodynamic parts and most widely used in turbomachinery. Rather than working individually, turbine blades are assembled on the rotor of turbomachinery to constitute bladed disks as the basic working units. Therefore, the quality of turbine blade assembly is crucial for guaranteeing the long and safe operation of turbomachinery with good performance. Aiming at this critical issue, two assembly error specifications of turbine blades are firstly defined as Circumferential Indexing Error and Axial Positioning Error, which are key factors affecting the throat and the incidence of turbine cascade. Then, the corresponding feature-based analysis methods are presented in this paper. Finally, the proposed theory and methods are experimentally verified through the bladed disk of a steam turbine rotor. The results demonstrate that the two defined assembly error specifications of turbine blades can be effectively extracted using the proposed methods. The assembly error of turbine blades can be used to evaluate the aerodynamic performance and the operating safety of turbine. Moreover, a guide can also be provided for the subsequent adjustment and correction of turbine blade assembly.