MODERNIZATION OF THE EXPERIMENTAL STAND FOR VALIDATION OF NUMERICAL MODELING OF SUPERCRITICAL CARBON DIOXIDE TO AIR AS A WORKING FLUID FOR TURBOMACHINES

By the middle of the century, electricity generation will more than double, leading to increased greenhouse gas emissions, which increase the likelihood of global warming. One of the most promising ways to generate electric energy is the Brayton cycle with supercritical carbon dioxide as a working fluid. This fluid has a high energy density and stable thermal and chemical properties. To further investigate the gas dynamics and structural characteristics of the turbine flow paths operating on supercritical carbon dioxide, it is necessary to create a full-scale experimental stand. However, the properties of the working fluid are not yet fully understood, that is why the creation of such a stand requires high costs and increased safety measures, since its operation is characterized by high temperature and pressure. In this work, supercritical carbon dioxide to air is simulated using the similarity technique. To validate numerical experiments conducted in Ansys Workbench software package, an experimental stand at Peter the Great St. Petersburg Polytechnic University was selected. A comprehensive evaluation of technical condition of the stand was conducted, and some units were replaced and modernized. As part of the stand preparation, thermal and resource calculations of the bearings were performed, and new oil injection nozzles for the bearings were designed and manufactured. Tests of the oil system were conducted, which showed that the volumetric flow rate meets the optimum values from the bearing technical data sheet. The volumetric flow rate of water in the system was also measured. A modern measuring system was developed, ensuring high experimental accuracy and allowing to obtain the main characteristics of the turbine in real time for further experimental studies.