Abstract: A bleed valve for a gas turbine engine includes a housing that defines an inlet upstream from an outlet. The bleed valve includes a poppet movable relative to the housing between a first position, in which the poppet closes the inlet, and a second position, in which the inlet is open and configured to receive a fluid flow. The housing defines a tortuous path for the fluid flow from the inlet to the outlet configured to reduce a pressure of the fluid flow from the inlet to the outlet within the housing. The tortuous path is defined by a plurality of rings positioned about the poppet, with each ring of the plurality of rings spaced apart from an adjacent ring of the plurality of rings between the inlet and the outlet to define the tortuous path.

Abstract: An alternating clockwise and counterclockwise helicoid cell structure for use in acoustic panels. The cell structure geometry may be easily replicated and tiled using additive manufacturing. The cell structure has at least an outer cavity and an inner cavity. The cavities are coaxial, share the same height, same entrance side, and same cell structure floor. The inner cavity includes a number of equal-volume inner chambers rotated uniformly in a first direction around the shared central axis; and the outer cavity includes a second number of equal-volume outer chambers rotated uniformly in an opposite direction to the first direction around the shared central axis. In various embodiments, one or more perforated baffles may extend, internally, across a chamber, perpendicular to direction of sound waves at the location of the perforated baffle. In various embodiments, one or more port openings from the outer cavity to the inner cavity may be present.

Abstract: An alternating clockwise and counterclockwise helicoid cell structure for use in acoustic panels. The cell structure geometry may be easily replicated and tiled using additive manufacturing. The cell structure has at least an outer cavity and an inner cavity. The cavities are coaxial, share the same height, same entrance side, and same cell structure floor. The inner cavity includes a number of equal-volume inner chambers rotated uniformly in a first direction around the shared central axis; and the outer cavity includes a second number of equal-volume outer chambers rotated uniformly in an opposite direction to the first direction around the shared central axis. In various embodiments, one or more perforated baffles may extend, internally, across a chamber, perpendicular to direction of sound waves at the location of the perforated baffle. In various embodiments, one or more port openings from the outer cavity to the inner cavity may be present.

Abstract: A bleed valve for a gas turbine engine includes a housing that defines an inlet upstream from an outlet. The bleed valve includes a poppet movable relative to the housing between a first position, in which the poppet closes the inlet, and a second position, in which the inlet is open and configured to receive a fluid flow. The housing defines a tortuous path for the fluid flow from the inlet to the outlet configured to reduce a pressure of the fluid flow from the inlet to the outlet within the housing. The tortuous path is defined by a plurality of rings positioned about the poppet, with each ring of the plurality of rings spaced apart from an adjacent ring of the plurality of rings between the inlet and the outlet to define the tortuous path.

Abstract: A nonlinearly stacked low noise turbofan stator vane having a characteristic curve that is characterized by a nonlinear sweep and a nonlinear lean is provided. The stator is in an axial fan or compressor turbomachinery stage that is comprised of a collection of vanes whose highly three-dimensional shape is selected to reduce rotor-stator and rotor-strut interaction noise while maintaining the aerodynamic and mechanical performance of the vane.