Large Eddy Simulation of Impinging Jets in a Confined Flow

Abstract

Large eddy simulation (LES) has been applied to a representative primary combustion zone in an isothermal constant density simulation. The primary combustion zone of a gas turbine combustor is known to be one of the most challenging combustor regions to study numerically. The main flow features are typically governed by the impingement characteristic of the multiple air admission jets that stem from the coupled feed annulus, resulting in high levels of turbulence, recirculation and unsteady/periodic flow conditions. The chosen cylindrical geometry consists of an annular passage that feeds a row of six port-holes. The resulting radial jets impinge strongly within a confined core cross-flow. Both uncoupled (core only) and coupled (core and annulus) simulations are considered. In the uncoupled simulation detailed experimental data is used to provide port boundary conditions, whilst the coupled simulation models the flow within the annulus and port openings. The findings conclude that the coupled LES can adequately reproduce the port characteristics resulting in a good description of the core combustor flow field, potentially superior to that given by the uncoupled case and far superior to that given by RANS.