Design of Dome Structure for A Lean Premixed Swirled Combustor of Gas Turbine Based on the Numerical Method

Abstract

To analyse the dome structure of the lean premixed swirled combustor, the influences of lance tip shapes, inflow air flow rates, numbers and locations of fuel nozzles and head expansion ratios on the combustion flame, flow field and flame dynamic response were investigated by computational fluid dynamics. The results show that the flame shape remains unchanged when the air velocity increases to a certain value. Increasing the number of fuel holes on the pressure surface, the high heat release rate area is concentrated in the root of the central recirculation zone. While increasing the number of fuel injectors on the pressure side and suction side makes the flame root temperature of the central recirculation zone lower, indicating a tendency to reduce the thermal NOx. Increasing the flame tube diameter helps the central recirculation zone to expand radially, resulting in longer flame branches. The axial length of flame will be shortened by changing the centre-lance tip from flat to ellipse. The amplitude and phase of flame transfer function are not affected by changing the centre-lance tip face shape, but the phase of flame transfer function is obviously changed by increasing the number of fuel holes.

Keywords

• gas turbine
• swirled premixed combustor
• dome structure
• fuel nozzle configuration
• combustion characteristic
• numerical simulation