Air turbine starter containment system
An air turbine starter for starting an engine, comprising a housing having an interior surface defining an interior, at least one turbine member rotatably mounted within the interior about a rotational axis, and having a plurality of circumferentially spaced blades, and a containment structure radially overlying and circumferentially surrounding the at least one turbine member extending between an outer surface and an inner surface to define a radial direction.
1. An air turbine starter for starting an engine, comprising:
a housing having an interior surface defining an interior;
at least one turbine member rotatably mounted within the interior about a rotational axis, and having a plurality of circumferentially spaced blades; and
a containment structure separate from the housing, the containment structure being disposed in the interior of the housing and radially overlying and circumferentially surrounding the at least one turbine member, the containment structure having:
a body extending between an inner surface and an outer surface, the body having a radial cross-section, the body having a plurality of ribs forming a respective portion of the inner surface; and
at least two circumferential grooves, with each circumferential groove of the at least two circumferential grooves being axially bounded by two axially adjacent ribs of the plurality of ribs;
wherein the plurality of ribs and the at least two circumferential grooves define regions of the containment structure that absorb an impact of a loose component from the at least one turbine member, the plurality of ribs being configured to stretch and deform when impacted by the loose component and retain the loose component within the containment structure after impact.
2. The air turbine starter of claim 1 , wherein:
each circumferential groove of the at least two circumferential grooves have a respective axial width defined as a maximum axial distance the circumferential groove extends in the radial cross-section; and
D at least two of the axial widths of the at least two circumferential grooves are non-equal.
3. The air turbine starter of claim 2 , wherein each circumferential groove of the at least two circumferential grooves terminates at a radially distal end within the containment structure, and includes a depth defined as a maximum radial distance between the distal end and the inner surface of the containment structure in the radial cross-section.
4. The air turbine starter of claim 3 , wherein at least two circumferential grooves of the at least two circumferential grooves include non-equal depths with respect to one another.
5. The air turbine starter of claim 3 , wherein the depth is larger than the axial width for each circumferential groove of the at least two circumferential grooves.
6. The air turbine starter of claim 1 , further comprising a transverse hoop stiffener extending axially along a respective portion of the inner surface.
7. The air turbine starter of claim 1 , wherein an axially forwardmost rib of the plurality of ribs defines a forward face of the body, and an axially rearmost rib of the plurality of ribs defines an aft face of the body.
8. The air turbine starter of claim 1 , further comprising at least one spring, wherein, during normal operation of the air turbine starter, the containment structure is configured to float against frictional resistance provided by the at least one spring, and further configured to become dislodged from the at least one spring and to rotate freely within the housing in response to the impact from the loose component of the at least one turbine member on the inner surface of the containment structure.
9. The air turbine starter of claim 1 , wherein the at least two circumferential grooves are provided within multiple circumferential grooves that form a symmetrical pattern in the radial cross-section.
10. The air turbine starter of claim 1 , wherein the at least two circumferential grooves are provided within multiple circumferential grooves, the multiple circumferential grooves having multiple asymmetrical grooves and at least one symmetrical groove where the symmetrical groove defines a symmetrical shape in the radial cross-section.
11. The air turbine starter of claim 10 , wherein the at least one symmetrical groove is axially centrally located within the multiple asymmetrical grooves, with respect to the rotational axis, and together with the multiple asymmetrical grooves forms a symmetrical pattern in the radial cross-section.
12. The air turbine starter of claim 1 , wherein each rib of the plurality of ribs includes an axial width in the radial cross-section, and wherein:
the axial width of the plurality of ribs is non-equal between ribs; or
at least one of the axial widths of the plurality of ribs is non-equal to at least one of the axial widths of the at least two circumferential grooves.
13. The air turbine starter of claim 12 , wherein the plurality of ribs form circumferential hoop stiffeners.
14. The air turbine starter of claim 1 , wherein the containment structure further comprises a plurality of locating tabs extending axially outward from a downstream end of the containment structure, the plurality of locating tabs locating the containment structure within the housing.
15. The air turbine starter of claim 1 , wherein the plurality of ribs are made of a different material than a remaining portion of the containment structure.
16. The air turbine starter of claim 1 , wherein the at least two circumferential grooves comprises:
a first circumferential groove having a first axial width;
a second circumferential groove, axially downstream of the first circumferential groove, having a second axial width; and
a third circumferential groove, axially downstream of the second circumferential groove, having a third axial width, equal to the first axial width;
wherein the second axial width is larger than the first axial width and the third axial width.
17. The air turbine starter of claim 1 , wherein:
a first circumferential groove of the at least two circumferential grooves includes an asymmetric shape in the radial cross-section; and
a second circumferential groove of the at least two circumferential grooves includes a symmetric shape in the radial cross-section.
18. The air turbine starter of claim 1 , wherein the containment structure further comprises at least one layer of shape memory alloy provided along one of the outer surface or the inner surface.
19. The air turbine starter of claim 1 , wherein the containment structure further comprises at least one layer of shape memory provided radially between the inner surface and the outer surface.
20. The air turbine starter of claim 1 , wherein the engine is a turbine engine.