Swirler ferrule plate having pressure drop purge passages

A swirler assembly of a combustor of a gas turbine, the swirler assembly defining a swirler centerline extended therethrough, a longitudinal direction extending along the swirler centerline, a radial direction extending outward from the swirler centerline, and a circumferential direction extending about the swirler centerline, the swirler assembly comprising:

• a primary swirler having a primary swirler flow opening therethrough;
• and
• a swirler ferrule plate connected to an upstream side of the primary swirler and including (a) a fuel nozzle opening extended therethrough, and (b) a plurality of oxidizer purge passages surrounding the fuel nozzle opening, each one of the plurality of oxidizer purge passages including (i) an inlet passage portion extending in the radial direction, and (ii) an outlet passage portion extending in the longitudinal direction from the inlet passage portion through a downstream surface of the swirler ferrule plate and having an outlet in fluid communication with the primary swirler flow opening, the outlet passage portion having an increasing cross-sectional area extending along a length of the outlet passage portion from the inlet passage portion to the outlet that induces a pressure drop in a flow of oxidizer through the oxidizer purge passage.