High-Loaded Compressor Blisk-Type Impeller Multidisciplinary Optimization

Abstract

The current work concerns the approach to the problem of the optimal design of experimental HPC blisk-type impellers. This approach is based on the use of modern optimization methods and a unified parameterized multidisciplinary 3D model, which was specially developed for the problem-solving method, which was formulated. The model included the HPC air-gas channel and the finite-element model of the HPC first stage impeller sector with one blade. At each optimization iteration a consecutive call to different parts of the unified model takes place and as a result the impeller sector and air-gas channel sector solid models, and the 3D strength and aerodynamic analysis computational grids are modified, and then the necessary characteristics are performed. This approach allows us to solve the problem of the agreement between the different requirements and the different impeller characteristics (aerodynamic, strength, weight, etc.), because these characteristics are carried out within unified computational space at each optimization iteration. During the process, according to the optimization problem statement, the characteristics of aerodynamics, strength, and weight are taken into account either as criterions or as restrictions. As an additional restriction, the design and technological requirements are used. The improvement in the structure characteristics is carried out by searching the optimal combination of dimensions using the optimizer IOSO. The approach described is applied for the improvement of HPC blisk-type first stage impeller characteristics. As an optimization criterion mass minimizing is used, as a restriction — the requirements are the static strength of the blade and disk, the condition of the blade in terms of dangerous resonance detuning, and the requirements for the conservation of stage and HPC pressure ratio, efficiency and flow rate. As a result of the optimization, when the first four natural resonance frequency detuning of the blade is carried out, the total impeller mass is reduced by approximately 10% and the aerodynamic characteristics remain unchanged. In addition, the disk weight is reduced by about 12%. At the same time, all the formulated restrictions on aerodynamic and strength characteristics are not broken. The total optimization process is automated and takes place without user participation.