STUDY OF SWIRLING AIR FLOW CHARACTERISTICS IN A LEAN DIRECT INJECTION COMBUSTOR

摘要

This paper investigates the non-reacting aerodynamic flow characteristics in Lean Direct Injection (LDI) combustors. The RANS modeling is used to simulate the turbulent, non-reacting, and confined flow field associated with a single-element and a nine-element LDI combustor. The results obtained from the simulation are compared with some experimental data available in literature. The numerical model, which is in accordance with an experimental combustor, consists of an air swirler with 6 helical axial vanes of 60 degree vane angle and a converging-diverging duct, extending in a square flame tube. The numerical model covers the entire flow passage, including the highly swirling flow passage through the swirler vanes, and the combustion chamber. Simulation has been performed with a low Reynolds number realizable k-ε model and a Reynolds stress turbulence model. It is observed that the computational model is able to predict the central re-circulation zones (CTRZ), the corner recirculation zones, and the complex flow field associated with the adjacent swirlers with reasonable accuracy. The computed velocity components for the single-element case show that the flow field is similar to the experimental observations.