Nowadays the optimization using computational fluid dynamics (CFD) plays an important role in the design process of turbomachines. However, for the successful and productive optimization it is necessary to define a simulation model correctly and rationally. The article deals with the choice of a grid and computational domain parameters for optimization of centrifugal compressor impellers using computational fluid dynamics. Searching and applying optimal parameters of the grid model, the computational domain and solver settings allows engineers to carry out a high-accuracy modelling and to use computational capability effectively. The presented research was conducted using Numeca Fine/Turbo package with Spalart-Allmaras and Shear Stress Transport turbulence models. Two radial impellers was investigated: the high-pressure at ѱT=0.71 and the low-pressure at ѱT=0.43. The following parameters of the computational model were considered: the location of inlet and outlet boundaries, type of mesh topology, size of mesh and mesh parameter y +. Results of the investigation demonstrate that the choice of optimal parameters leads to the significant reduction of the computational time. Optimal parameters in comparison with nonoptimal but visually similar parameters can reduce the calculation time up to 4 times. Besides, it is established that some parameters have a major impact on the result of modelling.

The aim of this work is the validation study for the numerical modeling of characteristics of a multistage centrifugal compressor for natural gas. In the research process was the analysis used grid interfaces and software systems. The result revealed discrepancies between the simulated and experimental characteristics and outlined the future work plan.

In the course of the work, the results of estimating the error in the numerical calculation of two-element 3D impeller stages of centrifugal compressors were obtained. Gas dynamic characteristics of 6 computational models of two-element stages of a centrifugal compressor are simulated. Based on available experimental data, models of validation characteristics have been performed. A parametric model has been developed for carrying out multi-criteria and multi-parametric studies.

In this work analysis, modernization and software implementation and an algorithm for thermodynamic calculation on the basis of the Benedikt-Webb-Rubin actual gas equation are performed. The work includes writing, analysis and modernization of the real gas thermodynamic calculation program. In the first part of the work data were processed to calculate real gas. In the second part, the development of the algorithm for thermodynamic calculation and its modifications is carried out. In the third part, the analysis of this algorithm is performed, revealing the main shortcomings and limits of applicability. In the fourth part of the work, the algorithm was implemented in the form of computational modules and programs, and also practical testing of these programs in the calculation of gas compressor and auxiliary equipment.

Design modernization of the centrifugal compressor stage test bench with three dimensional impeller blades was carried out for the possibility of holding a series of experimental studies of different 3D impeller models. The studies relates to the problem of joint work of the impeller and the stationary channels of the housing when carrying out works on modernization with the aim of improving the parameters of the volumetric capacity or pressure in the presence of design constraints. The object of study is the experimental single end centrifugal compressor stage with the 3D impeller. Compressor stage consists of the 3D impeller, vaneless diffuser (VLD), outlet collector - folded side scroll and downstream pipe. The drive is a DC motor 75 kW. The increase gear (multiplier) was set between the compressor and DC motor, gear ratio is i = 9.8. To obtain the characteristics of the compressor and the flow area the following values were measured: total pressure, static pressure, direction (angles) of the stream in different cross sections. Additional pneumometric probes on the front wall of the VLD of the test bench have been installed. Total pressure probes and foster holes for the measurement of total and static pressure by the new drainage scheme. This allowed carrying out full experimental studies for two elements of centrifugal compressor stage. After the experimental tests the comprehensive information about the performance of model stage were obtained. Was measured geometric parameters and the constructed virtual model of the experimental bench flow part with the help of Creo Parametric 3.0 and ANSYS v. 16.2. Conducted CFD calculations and verification with experimental data. Identifies the steps for further experimental and virtual works.