Patent ID: 7086854

Claim:
A combustor comprising: a reactor; an inlet for admitting a main flow of fluid to said reactor; an exit for discharging heated fluid from said reactor; said reactor positioned between said inlet and said exit and comprising a main flow zone, through which a majority of said main flow passes along a main flow path, and a recirculation zone, through which a lesser portion of said main flow passes; wherein said recirculation zone is defined in part by a wall having an interior surface curved in one direction in a substantially continuous manner and running from a take off point proximate to said exit to a return point proximate to said inlet, said interior surface being shaped and positioned with respect to said main flow path in such a manner as to divert part of the fluid in said main flow path at said take off point to form a recirculation vortex flow in said recirculation zone during the operation of said reactor; and wherein said interior surface is further characterized by a lack of discontinuities so as to cause substantially undisturbed movement of a boundary layer along the periphery of said recirculation vortex flow.