Centrifugal compressor stage impeller optimization by one-dimensional, quasi-three-dimensional and CFD methods

The aim of the research is to optimize the 3D impeller and compare various methods of its design, evaluate the influence of each of the considered parameters, and develop recommendations for the optimal design. The meridional form of the 3D impeller was optimized, as well as the shape of the blade row. The meridional form of 3D impeller was researched using the Universal Modeling Method, the profiling of the impeller blades was carried out in the program of inviscid quasi-three-dimensional calculation 3DM.023. Since experimental verification of all designed impellers is not possible, the model tests were replaced by virtual ones, i.e. by CFD calculations. We have designed ten variants of 3D impeller using the program calculating inviscid quasi-three-dimensional flows, and researched blades height at the impeller exit, "gas-dynamic" and "geometric" approaches of blade profiling, the variation of the exit blade angle along blades height, the exit bulk angle, and the impeller axial length. Using a mathematical model, we have researched the influence of several impeller geometric parameters, such as impeller axial length, impeller inlet diameter, blade leading edge position, exit blade height, and number of blades. The research made it possible to increase the efficiency of the stage in all operating modes, the efficiency of the stage at the design point was increased by 1.02%, and the characteristic efficiency was increased by an average of 0.88%.