Centrifugal compressor for low flow rates

U ovom je diplomskom radu ispitana mogućnost višestupanjske izvedbe centrifugalnog kompresora za velike brzine vrtnje i male dobave, aerodinamičkom i termodinamičkom analizom strujanja zraka. Glavni dio proračuna strujanja zraka kroz kompresor je proveden metodom kontrolnih volumena u komercijalnom paketu Ansys Fluent, dok je geometrijska domena diskretizirana nestrukturiranom kartezijskom mrežom konstruiranom u CF-MESH+ alatu, baziranom na inside-out metodologiji. Proračun i dimenzioniranje pojedinih komponenti kompresora proveden je u programskom jeziku Python. Rekonstrukcija kompresora za prednabijanje je zapravo postupak obrnutog inženjerstva, ali uz korištenje standardnih procedura projektiranja rotorskih lopatica. Prestrujni kanal i statorske lopatice su dimenzionirane prema preporukama iz literature, te uz cilj što manjih gubitaka. Usporedbom rezultata provedenih simulacija pokazano je kako dodavanjem prestrujnog kanala ne dolazi do velikog pada zaustavnog tlaka i iskoristivosti kompresora u odnosu na jednostupanjsku izvedbu sa spiralnim kućištem.In this Master's thesis the possibility of a multi-stage design of a centrifugal compressor for high rotational speeds and low flow rates, was examined by aerodynamic and thermodynamic analysis of airflow. The main part of the calculation of the airflow through the compressor was carried out using the finite volume method in commercial package Ansys Fluent, while the geometric domain was discretized with a unstructured Cartesian mesh, constructed in the CF-MESH+ tool, that is based on inside-out method. Calculation and dimensioning of individual components of the compressor was carried out in the programming language Python. The reconstruction of the precharger compressor is actually a reverse engineering process, but with the use of standard methods for designing rotor blades. The return channel and stator vanes are dimensioned according to recommendations from the literature, and with the aim of reducing losses as much as possible. By comparing the results of the simulations, it was shown that the addition of a return channel does not result in a large stagnation pressure and efficiency drop compared to the single-stage configuration with spiral volute