A gas turbine engine is shown having an annular burner with a plurality of staged premixing tubes extending from the forward end thereof. Each tube directs flow to the burner through two concentric flow passages. A movable tube section is arranged to direct all the air through both flow passages or just through one passage. Fuel is directed into the staged premixing tube for mixing with air flowing therethrough. Swirl vanes are provided in each of the flow passages to provide for rotation of air passing therethrough. A centerbody is positioned within the inner flow passage providing a bluffbody to promote recirculatory flow in the general region rearwardly of the centerbody. Cooling is provided around the primary zone of the burner so as to provide a minimum of cooling flow into the primary zone.
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