The main injector of a lean premixed prevaporized(LPP) gas turbine combustor for reducing NOx emissions starts to operate from a point where a certain level of thrust is reached and controls to a high thrust. The radial swirler mounted on the main injector plays a large role in thrust control and contributes to stable thrust control. In this paper, the flow characteristics of the air injected from the chamber according to the change of the swirl number are obtained by using Particle Image Velocimetry (PIV), and the flow velocity and spray angle according to the injection position are measured to check the influence of air flow. It was confirmed that the radial swirler, like the axial swirler, also increased the recirculation area as the swirl number increased. When the aerosol was injected into the atmosphere using a radial swirler, the spray angle increased as the number of turns increased, and when the number of turns exceeded a certain number of turns, the aerosol could not move forward direction. This means that the swirl number is increased, when the back pressure gradient is largely formed in front of the slewing machine, the flow must be structurally supplemented so that the flow can proceed forward.

Lean premixed prevaporized, Main injectors, Radial swirlers, Particle image velocimetries, Swirl number, Gas turbine combustors