Numerical modelling of spray and combustion processes in a jet engine combustion chamber

U ovom radu, izvršeno je numeričko modeliranje procesa spreja i izgaranja unutar komore za izgaranje mlaznog motora. Promatrana komora sastoji se od dvostupanjskog radijalnog vrtložnika koji se koristi za induciranje vrtloga zraka. Na ulazu u komoru propisan je konstantan protok zraka kako bi se osiguralo dovoljno kisika u zoni izgaranja. U ovom radu tekuće gorivo Jet-A korišteno je kao zamjena za kerozin. Za modeliranje turbulentnog strujanja korišten je napredni k-ζ-f model turbulencije, dok je za opisivanje procesa spreja korišten Euler Lagrangeov pristup modeliranja spreja. Proces izgaranja modeliran je pomoću ECFM-3Z modela izgaranja dok je proces zapaljenja modeliran korištenjem ISSIM modela zapaljenja. Utjecaj spreja analiziran je provođenjem simulacija s različitim kutom spreja. Verificirani su prezentirani rezultati, kao što su temperaturna raspodjela, profili brzine te koncentracija emisija kroz komoru za izgaranje. S obzirom na dobivene rezultate, može se zaključiti da je postignuto ispravno fizikalno i kemijsko ponašanje unutar komore izgaranja. Sve simulacije su odrađene u komercijalnom RDF programu AVL FIRE™.In this thesis, numerical modelling of combustion process in a can type combustion chamber of a jet engine is presented. The observed chamber is designed with a double stage radial swirler used to induce air vortices. The constant mass flow air is defined at the combustion chamber inlet in order to supply the combustion zone with fresh oxygen. The liquid fuel Jet-A was used as a surrogate for the kerosene fuel. To model the turbulent behaviour, the advanced k-ζ-f turbulence model was utilised, whilst the spray process was described by using the Euler Lagrangian approach. The combustion process was described with the ECFM-3Z combustion model, and the ignition was modelled with the Imposed stretch spark ignition model. The influence of droplet spreading angle on the combustion process was analysed. Presented results, such as temperature distribution, velocity profiles, and emission concentrations through the entire combustion chamber were verified. According to the provided results, a correct chemical and physical behaviour of the chosen setup was achieved. All simulations were performed with the commercial computational fluid dynamic software AVL FIRE™