Patent ID: 7421843

Claim:
A combustor comprising: a catalytic combustion stage receiving a first portion of a total oxidizer flow and a first portion of a total fuel flow and discharging a partially combusted fuel/oxidizer mixture; a post catalytic combustion stage defined by a combustion liner and receiving the partially oxidized fuel/oxidizer mixture along a flow axis; an injector scoop in fluid communication with an opening in the combustion liner and having an injector scoop inlet for receiving a second portion of the total oxidizer flow; a fuel outlet selectively supplying a second portion of the total fuel flow into the second portion of the oxidizer flow; and an injector scoop outlet in fluid communication with the post catalytic combustion stage and discharging a fuel/oxidizer mixture of the second portion of the total oxidizer flow and the second portion of the total fuel flow into the partially combusted fuel/oxidizer mixture at an angle relative to the flow axis to impart a swirl to the fuel/oxidizer mixture as it enters the post catalytic combustion stage; wherein the injector scoop inlet comprises a larger cross sectional area than a cross sectional area of the injector scoop outlet to accelerate the fuel/oxidizer mixture entering the post catalytic combustion stage to a velocity greater than a velocity of the partially combusted fuel/oxidizer mixture to avoid flame holding.