Application of the GEKO Turbulence Model for Numerical Calculation of Axial-flow Compressors

The aim of the study is to determine the possibility of using the GEKO turbulence model in the fluid dynamic computation of axial-flow compressors by a numerical method. To achieve the goal, isolated validation examples were calculated on various configurations of the turbulence model. The calculation results have shown that the GEKO turbulence model enables the user to adjust the flow separation onset, making it earlier, later, or completely excluding it. With such adjustment, the boundary layer basic calibration is retained. The research methodology consists in carrying out variant calculations on different configurations of the turbulence model, followed by a comparative analysis with experimental data. The study has shown that the results of calculations of an experimental axial-flow compressor are in the nominal mode. It is noted that by calibrating the GEKO turbulence model it is possible to refine the calculated stage pressure coefficient value and come closer to the experimental value. The refinement mechanism consists in predicting more correct lagging angles in the rotor blade cascade due to a more correct prediction of flow separation from the blade suction side on the optimal configuration of the computational model. Thus, the turbulence model makes it possible to adjust the computation in some useful range to achieve a more accurate solution. The computation model calibration regularities have been studied, which can be used in fluid dynamic calculations when designing axial-flow compressors.