The paper focuses on the problem of a possible expansion of the range of operating modes of a centrifugal natural gas compressor due to the rotation of the inlet guide vanes at different rotor speeds. The geometry of the flow path of the investigated object, obtained by three-dimensional scanning, is presented. On its basis, a numerical model is built and the influence of various factors of the formulation of the computational problem on the results of modeling the gas flow in the flow path of the compressor is analyzed. The calculations were performed using the k--ε and SST turbulence models for various parameters of the computational grid and conditions for averaging the flow parameters between the computational domains. The results obtained were compared with the nameplate and operational data. Recommendations on the formulation of the modeling problem are proposed, the results of the calculations are described, and the characteristics of the centrifugal compressor are plotted at different angles of the inlet guide vanes in a wide range of rotor speeds. The possible range of expansion of the operating modes of the investigated compressor is described, which can be provided by varying the position of the inlet guide vane