A Numerical Analysis on the Characteristics of Spray by Swirl Injector in Gas Turbine Combustor

가스터빈연소기에서 스월 인젝터의 분무특성에 관한 연구

The present paper deals with the numerical simulation for the spray characteristics with swirling turbulent flows and dilution flows from swirl injectors in a simplified can type of gas turbine combustor. The main objective is to investigate the characteristics of swirling turbulent flows with dilution flows and to provide the qualitative results for the spray characteristics such as the droplet distribution and Sauter Mean Diameter(SMD). The gas-phase equations based on Eulerian approach were discretized by Finite Volume Method, together with SIMPLE algorithm and the Reynolds -Stress-Model. The liquid-phase equations based on Lagrangian method were used to predict the droplet behavior. The results of preliminary test are generally in good agreement with experimental data, and show that the anisotropy exists in the primary zone due to swirl velocity and injected air from primary injector, and then gradually decays due to turbulent mixing and consequently near-isotropy occurs in the region between primary and dilution zones. For the spray characteristics, it is indicated that the swirling flows of primary jet region increase the droplet atomization. In addition, it is showed that the swirling flows at the inlet region lead the air-fuel mixture to be distributed near the igniter and can significantly affect the spray behavior in the primary jet region.