Аналіз роботи робочого колеса нагнітача при транспортуванні природного газу та газо-водневої суміші

The research object is the impeller of a centrifugal compressor used in gas-pumping units of main gas pipelines under conditions of transporting natural gas and its mixtures with hydrogen. This study aims to determine the impact of hydrogen addition to natural gas on gas-dynamic parameters and compressor efficiency and to assess the operating limits of existing equipment. The research objectives include: investigating changes in the fundamental physicochemical properties of gas with hydrogen addition; performing mathematical calculations for compressor operating modes at hydrogen concentrations of 0%, 5%, 10%, 15%, and 20% H₂; conducting Computational Fluid Dynamics (CFD) analysis of the gas flow in the impeller using ANSYS CFX for different hydrogen concentrations; comparing the obtained results; and determining the influence of gas composition on compressor parameters (pressure, temperature, velocity, efficiency, etc.). The following methods were used for solving the tasks: analytical calculation (using Mathcad software) and numerical-experimental method (CFD modeling in ANSYS CFX). Obtained results: An increase in the hydrogen volumetric fraction significantly reduces the gas density, causing a decrease in the compressor’s generated pressure, temperature, and efficiency. The rising hydrogen content shifts the compressor’s operating point toward higher flow rates and closer to surge conditions, narrowing the stable operation region by approximately 30% at 20% hydrogen concentration. Conclusions. The addition of hydrogen to natural gas significantly affects the performance of centrifugal compressors by reducing gas density, lowering efficiency, and limiting the stable operating range. To ensure stable operation during transportation of gas-hydrogen mixtures, adjustments in compressor operation modes-specifically, increasing flow rates or rotational speed, are necessary. The results obtained allow evaluation of existing equipment limits and provide recommendations for modernization to enable efficient transportation of gas-hydrogen mixtures.