Premix combustor with flow constricting baffle between combustion and

Abstract

A combustion liner for a gas turbine combustion apparatus has a wall of circular cross-section defining a primary air entrance at its upstream end, providing means for introduction of fuel near the upstream end, having a convergent-divergent fuel prevaporization zone, a reaction zone, and a dilution zone. The primary air entrance has two coaxial entrance portions separated by an annular intermediate wall disposed around a centerbody. Swirlers in the two entrance portions swirl the air with different degrees of swirl, which provides shear between the two layers downstream of the swirlers. Fuel is introduced onto the intermediate or outer wall, or both, upstream of the throat. Air is admitted through the centerbody and directed towards the throat at higher fuel flow rates, but is shut off by a valve plug at low fuel flow rates to promote recirculation and thus improve flame stability under such conditions. The valve responds to fuel and combustion air pressure. A pilot fuel nozzle is mounted on the valve plug in the centerbody outlet. Recirculation from the dilution zone into the reaction zone is controlled by an annular barrier extending inwardly from the liner wall between the two zones. Air is circulated through the barrier adjacent the walls of the barrier to cool it. Means are provided for varying the primary and secondary air flow areas.