A secondary fuel delivery system comprising: an elongated transition piece adapted to fluidly connect a primary combustion zone and a combustion engine turbine section, said transition piece comprising an elongated boundary wall surrounding a secondary combustion zone; a manifold formed integral with said boundary wall, said manifold including an inlet port adapted to fluidly link a manifold interior with a source of secondary fluid (128, 130); a plurality of injector nozzles (124, 126) fluidly linking said manifold interior with said secondary combustion zone; a flow acceleration region located within said manifold at a location where non-accelerated secondary fluid flow velocity is less than about 60% of the secondary fluid flow velocity exhibited proximate said inlet port; a flowsleeve located within said flow acceleration region, said flowsleeve adapted to increase fluid flow volume within said acceleration region to a level between about 65% to 120% of said secondary fluid flow velocity exhibited proximate said inlet port, whereby said manifold exhibits increased stiffness and is resistant to vibration generated by said transition piece and wherein said flowsleeve compensates for secondary fluid cooling effectiveness losses at a region flow-wise-away from said inlet port, characterized in that said flowsleeve includes a blocking band having apertures through which said nozzles (124, 126) extend, said apertures sized to allow said secondary fluid (128, 130) to flow radially outward, away from a manifold radially-inward boundary, along exteriors of said nozzles (124, 126) and then change direction to enter and flow through the nozzles (124, 126), before exiting the manifold and travelling into the secondary combustion zone. an elongated transition piece adapted to fluidly connect a primary combustion zone and a combustion engine turbine section, said transition piece comprising an elongated boundary wall surrounding a secondary combustion zone; a manifold formed integral with said boundary wall, said manifold including an inlet port adapted to fluidly link a manifold interior with a source of secondary fluid (128, 130); a plurality of injector nozzles (124, 126) fluidly linking said manifold interior with said secondary combustion zone; a flow acceleration region located within said manifold at a location where non-accelerated secondary fluid flow velocity is less than about 60% of the secondary fluid flow velocity exhibited proximate said inlet port; a flowsleeve located within said flow acceleration region, said flowsleeve adapted to increase fluid flow volume within said acceleration region to a level between about 65% to 120% of said secondary fluid flow velocity exhibited proximate said inlet port, whereby said manifold exhibits increased stiffness and is resistant to vibration generated by said transition piece and wherein said flowsleeve compensates for secondary fluid cooling effectiveness losses at a region flow-wise-away from said inlet port, characterized in that said flowsleeve includes a blocking band having apertures through which said nozzles (124, 126) extend, said apertures sized to allow said secondary fluid (128, 130) to flow radially outward, away from a manifold radially-inward boundary, along exteriors of said nozzles (124, 126) and then change direction to enter and flow through the nozzles (124, 126), before exiting the manifold and travelling into the secondary combustion zone.