Manufacturing and Build Variations Modelling for Multi-Stage Axial Compressors: Forced Response Predictions

Abstract Modern multi-stage axial compressors for gas turbine applications continue to require the achievement of higher efficiency whilst at the same time meeting the mechanical integrity and life requirements that have established the gas turbines as a key asset in many industrial applications. To avoid potential aero-mechanical issues, the development and validation of computationally efficient and accurate numerical tools is of paramount importance. This paper demonstrates how highly automated forced response analyses are integrated in the design of a new multistage axial compressor for industrial gas turbine applications. In case of twin-shaft engines with wide operating range requirements, each design concept can require hundreds of analyses. The capability to perform rapid design iterations considering aero-mechanical stability, unlocks new regions of the design space excluded by traditional design criteria, with potential issues being identified and rectified at an early stage in the product development process. Moreover, the scope of the assessments can be extended to consider effects which would not traditionally be considered as part of the design process, such as mistuning due to manufacturing variations. The methodology is here applied to in-tolerance geometrical variations, modelling the associated uncertainty on forced response. Characterizing the sensitivity to manufacturing variations provides actionable data for the development of robust design concepts. The methodology used for the design of a new compressor and subsequent predictions are validated against tip timing data from a full-scale engine test, demonstrating the accuracy of both the analyses and design process.