A method for matching compressor stage characterstics to a given load profile by operating point weighting
A method for the design and revamp of turbomachinery components based on a given load profile is developed and introduced. The procedure is verified by optimizing a single stage vaned centrifugal compressor with respect to different load profiles. A robust optimization methodology is used for carrying out fully automated efficiency optimization on the entire operating range. Three operating point weighted optimization functions are introduced and used as the optimization criterion (objective function). The corresponding efficiencies are calculated by full-stage 3D flow simulation and looped in an automated direct (no meta-model) optimization process using the Adaptive Response Surface Method (ARSM). The aim of the methodology is the utilization of the weighting factors to actively control the operating points (pursuant to their application in a late design or as part of a machinery revamp) and to optimize the efficiency correspondingly. In the test case considered in this work, the diffuser vanes of a centrifugal compressor stage are fully automatically optimized for different distributions of the weighting factors. The procedure for calculating an optimized geometry comprises the setup of a robust workflow and the translation of the load profile into an optimization criterion including boundary definitions. In the test case, nine diffuser design parameters are varied and directly optimized using the direct ARSM. The active control of the efficiency-characteristic between the operating points was verified by varying different weighting factor distributions for two versions (shrouded and unshrouded) of a basic impeller. Results prove the capability of this methodology of matching a stage characteristic to a given load profile.