An axially staged combustion system comprising: a combustion liner having an inlet end , an outlet end , and a first combustion chamber positioned therebetween; a transition duct in fluid communication with the combustion liner ; a premixer positioned generally between the combustion liner and the transition duct for providing a homogeneously mixed flow of fuel and air to a second combustion stage spaced axially downstream from the first combustion chamber , the premixer comprising: a plurality of vanes oriented in both a tangential and axial direction, thereby forming channels therebetween with each channel having a slot length, slot height, slot width and a bottom surface; and, a plurality of fuel injectors positioned to supply fuel to the channels ; wherein the fuel and air passes through the plurality of channels positioned radially outward of the combustion liner such that the fuel and air is imparted with a swirl and directed radially inward proximate the outlet end of the combustion liner to enter a region between the combustion liner and the transition duct ; characterized in that the channels pass adjacent to a portion of the combustion liner and tapers radially inward towards an outlet end of the combustion liner . a combustion liner having an inlet end , an outlet end , and a first combustion chamber positioned therebetween; a transition duct in fluid communication with the combustion liner ; a premixer positioned generally between the combustion liner and the transition duct for providing a homogeneously mixed flow of fuel and air to a second combustion stage spaced axially downstream from the first combustion chamber , the premixer comprising: a plurality of vanes oriented in both a tangential and axial direction, thereby forming channels therebetween with each channel having a slot length, slot height, slot width and a bottom surface; and, a plurality of fuel injectors positioned to supply fuel to the channels ; wherein the fuel and air passes through the plurality of channels positioned radially outward of the combustion liner such that the fuel and air is imparted with a swirl and directed radially inward proximate the outlet end of the combustion liner to enter a region between the combustion liner and the transition duct ; characterized in that the channels pass adjacent to a portion of the combustion liner and tapers radially inward towards an outlet end of the combustion liner . a plurality of vanes oriented in both a tangential and axial direction, thereby forming channels therebetween with each channel having a slot length, slot height, slot width and a bottom surface; and, a plurality of fuel injectors positioned to supply fuel to the channels ; wherein the fuel and air passes through the plurality of channels positioned radially outward of the combustion liner such that the fuel and air is imparted with a swirl and directed radially inward proximate the outlet end of the combustion liner to enter a region between the combustion liner and the transition duct ; characterized in that the channels pass adjacent to a portion of the combustion liner and tapers radially inward towards an outlet end of the combustion liner . <EOS>