Acoustic damper with barrier member configured to dampen acoustic energy propogating upstream in gas flow
View Patent ↗An acoustic damper includes a housing with an inlet aperture and an outlet aperture. The housing is configured to receive a gas flow that enters via the inlet aperture and that exits via the outlet aperture. The acoustic damper also includes a barrier member that is disposed within the housing. The barrier member is configured to be disposed within the gas flow and to dampen acoustic energy that propagates in an upstream direction generally from the outlet aperture toward the inlet aperture. The barrier member includes an outer structure that defines an interior volume of the barrier member. The interior volume is oriented toward the outlet aperture.
1. An acoustic damper comprising:
a housing that includes an inlet aperture and an outlet aperture, the housing configured to receive a gas flow that enters via the inlet aperture and that exits via the outlet aperture; and
a barrier member that is disposed within the housing, the barrier member configured to be disposed within the gas flow, the barrier member including an outer structure that defines an interior volume of the barrier member, the interior volume oriented toward and open to the outlet aperture, the barrier member configured for dampening acoustic energy that propagates in an upstream direction from the outlet aperture toward the inlet aperture;
the outer structure containing at least one of:
a resonator contained within the interior volume of the outer structure; and
an acoustic dampening material contained within the interior volume of the outer structure.
2. The acoustic damper of claim 1 , wherein the outer structure is an outer shell that includes an upstream end, a downstream end, and an axis that extends between the upstream end and the downstream end;
wherein the outlet aperture is aligned with the axis of the outer shell.
3. The acoustic damper of claim 2 , wherein the inlet aperture is aligned with the axis of the outer shell.
4. The acoustic damper of claim 2 , wherein the outer shell is symmetrical about the axis.
5. The acoustic damper of claim 1 , wherein the outer structure includes an upstream end, a downstream end, and an axis that extends between the upstream end and the downstream end; and
wherein the outer structure has a width that increases from the upstream end to the downstream end along the axis.
6. The acoustic damper of claim 5 , wherein at least part of the outer structure tapers in width along the axis.
7. The acoustic damper of claim 6 , wherein the outer structure has one of a conic shape and a frusto-conic shape.
8. The acoustic damper of claim 6 , wherein the outer structure has an exterior surface with three dimensional contour.
9. The acoustic damper of claim 1 , wherein the outer structure contains a plurality of quarter-wave resonators that are arranged in-parallel within the interior volume.
10. The acoustic damper of claim 1 , further including an acoustic dampening material that is supported by at least one of the outer structure within the interior volume and the housing.
11. The acoustic damper of claim 1 , wherein the inlet aperture defines an inlet cross sectional area;
wherein a flow cross sectional area is defined between the barrier member and the housing;
wherein the barrier member defines an upstream end, a downstream end, and a length measured from the upstream end to the downstream end; and
wherein the flow cross sectional area is at least equal to the inlet cross sectional area along an entirety of the length of the barrier member.
12. The acoustic damper of claim 1 , wherein the outer structure is an outer shell that includes an upstream end, a downstream end, and an axis that extends between the upstream end and the downstream end;
wherein the downstream end terminates at a downstream lip;
wherein the outer structure contains a plurality of resonators including a first resonator with a first free end and a second resonator with a second free end; and
wherein the first free end and the second free end terminate in a common radial plane with the downstream lip, the common radial plane extending radially with respect to the axis.
13. The acoustic damper of claim 1 , wherein the outer structure is an outer shell that includes an upstream end, a downstream end, and an axis that extends between the upstream end and the downstream end;
wherein the outer structure contains a plurality of resonators surrounding the axis, the plurality of resonators having different radii, and the plurality of resonators spaced apart at a consistent radial distance between adjacent ones of the plurality of resonators.
14. The acoustic damper of claim 1 , wherein the outer structure includes an upstream end, a downstream end, and an axis that extends between the upstream end and the downstream end; and
wherein the upstream end includes a projection extending along the axis toward the inlet aperture.
15. The acoustic damper of claim 1 , wherein the outer structure includes an upstream end, a downstream end, and an axis that extends between the upstream end and the downstream end; and
wherein the downstream end is contoured inward radially toward the axis.
16. An acoustic damper comprising:
a housing that includes an inlet aperture and an outlet aperture, the housing configured to receive a gas flow that enters via the inlet aperture and that exits via the outlet aperture;
a barrier member that is disposed within the housing, the barrier member configured to be disposed within the gas flow, the barrier member including an outer structure that defines an interior volume of the barrier member, the interior volume oriented toward the outlet aperture, the barrier member configured for dampening acoustic energy that propagates in an upstream direction generally from the outlet aperture toward the inlet aperture; and
the barrier member including at least one resonator disposed within the interior volume, the at least one resonator including at least one inner wall that is connected to the outer structure and that defines a chamber within the interior volume;
wherein the at least one inner wall includes an opening; and
wherein the at least one inner wall, the opening, and the chamber are configured to define a Helmholtz-type resonator.
17. An acoustic damper comprising:
a housing that includes an inlet aperture and an outlet aperture, the housing configured to receive a gas flow that enters via the inlet aperture and that exits via the outlet aperture;
an outer shell that is disposed within the housing and configured to be disposed within the gas flow, the outer shell including an upstream end, a downstream end, and an axis that extends between the upstream end and the downstream end, the outer shell having an outer width that is measured perpendicular to the axis, the outer width gradually increasing from the upstream end to the downstream end along the axis, the outer shell defining an interior volume, the downstream end including an opening into the interior volume;
at least one resonator that is supported by the outer shell within the interior volume, the at least one resonator including at least one inner wall that is connected to the outer shell and that defines a chamber within the interior volume, the at least one inner wall including an opening; and
the at least one inner wall, the opening, and the chamber being configured to define a Helmholtz-type resonator.
18. The acoustic damper of claim 17 , wherein the at least one resonator includes a plurality of Helmholtz-type resonators.
19. The acoustic damper of claim 17 , further including an acoustic dampening material that is supported by at least one of the outer shell within the interior volume and the housing.
20. The acoustic damper of claim 17 , wherein the outlet aperture is aligned with the axis of the barrier member.