Influence of Atomization Characteristics on Lean Blow-Out Limits in a Gas Turbine Combustor

Abstract

In order to investigate the effects of atomization characteristics on the lean blow-out (LBO) performance, an experimental study was carried out on the spray and the combustion. The LBO limits and the outlet temperature near the LBO condition of different atomizers were measured in a single dome rectangular model combustor with a dual-radial and a dual-axial swirl cup, respectively. In the combustor, the spray analysis was performed on different atomizers (without combustion) at the LBO condition. The Malvern particle size analyzer was used to measure the Sauter Mean Diameter (SMD), and the laser sheet was used to take spray images. First of all, the spray pattern determines the minimum heat release required to maintain the combustion, which corresponds to the ideal LBO fuel/air ratio (FAR), which is the maximum potential for the lean combustion. Secondly, the matching of the spray SMD, the droplet size spatial distribution and the droplet initial velocity with the flow field determines the ratio of the completely burned fuel to the total fuel ejected from the atomizer, which determines the extent to which the combustor exerts its lean combustion potential. In addition, the numerical simulation of the flow field of the combustor with two structures was carried out, which provided an important basis for the theoretical analysis of this paper.