초록 ▼

A variable area flow duct and method. In one embodiment the flow duct includes a plurality of helical vanes arranged around an interior surface wall of the flow duct. The vanes cause secondary flow vortices to be developed in the vicinity of each of the vanes that effectively reduce the interior cro

A variable area flow duct and method. In one embodiment the flow duct includes a plurality of helical vanes arranged around an interior surface wall of the flow duct. The vanes cause secondary flow vortices to be developed in the vicinity of each of the vanes that effectively reduce the interior cross-sectional area of the duct that a primary flow sees as it flows through the duct. In various embodiments fluidic injection is employed to suppress the formation of the secondary flow vortices during certain phases of operation, for example, during an afterburn phase of operation of a jet aircraft engine which the flow duct is being used with. In another embodiment, an ablative coating is used over the vanes to suppress the formation of the secondary flow vortices. The ablative material is removed by the hot fluid flow during an afterburn phase of operation, thus exposing the vanes and enabling the subsequent formation of secondary flow vortices to narrow the cross-sectional area of the throat.

대표청구항 ▼

What is claimed is: 1. A flow duct comprising:a circumferential wall having an inner surface, the inner surface defining a fluid flow path for a primary flow flowing through the flow duct; andat least one curving projection forming a non-moveable vane, and formed to project from the circumferential

What is claimed is: 1. A flow duct comprising:a circumferential wall having an inner surface, the inner surface defining a fluid flow path for a primary flow flowing through the flow duct; andat least one curving projection forming a non-moveable vane, and formed to project from the circumferential wall of the inner surface of the flow duct such that the non-moveable vane projects radially inwardly toward an axial center of the flow duct and non-parallel to a longitudinal centerline extending along the axial center of the flow duct, the non-moveable vane for generating a secondary flow adjacent the inner surface that effectively reduces an internal cross-sectional area of the duct for said primary flow.