Blade outer air seal segment assembly using sleeve-rail configuration and method
A blade outer air seal (BOAS) segment of a gas turbine engine includes a support component extending circumferentially in an arc and an arcuate ceramic matrix composite (CMC) sleeve that slides onto the support component. The support component may be made of metal such as a high Nickel (Ni) content alloy or a high Cobalt (Co) content alloy and includes a pair of rails. The CMC sleeve can be formed of a plurality of stacked plies to have a uniform thickness, and include arcuate upstream and downstream curves to engage the pair of rails. The CMC sleeve can be uniformly densified and maintain a uniform thermal gradient. A flexible insulation blanket formed of carbon/graphite felt may be disposed between the rails of the support component and the CMC sleeve to avoid the need to cool the support component.
1 . A blade outer air seal (BOAS) segment of a gas turbine engine, comprising:
a support component extending circumferentially in an arc, the support component having a uniform axial cross section that includes:
a central portion extending axially from an upstream end to a downstream end;
a first support flange extending radially outward from the upstream end of the central portion;
a second support flange extending radially outward from the downstream end of the central portion;
a first rail extending axially from the upstream end of the central portion, the first rail terminating with a first circular cross section; and
a second rail extending axially from the downstream end of the central portion, the second rail terminating with a second circular cross section; and
a ceramic matrix composite (CMC) sleeve extending circumferentially in an arc, the CMC sleeve formed of a plurality of stacked plies to have a uniform thickness and having a uniform axial cross section that includes:
an arcuate upstream curve dimensioned to slide onto the first circular cross section;
an arcuate downstream curve dimensioned to slide onto the second circular cross section; and
an axial portion extending between the arcuate upstream curve and the arcuate downstream curve,
wherein the CMC sleeve is attached to the support component by circumferentially sliding onto the first and second rails, and
wherein the support component is formed of metal.
2 . The BOAS segment of claim 1 , wherein the metal is a Nickel (Ni) containing alloy or a Cobalt (Co) containing alloy.
3 . The BOAS segment of claim 1 , wherein the arcuate upstream curve is dimensioned to wrap around more than 180° of the first circular cross section; and
the arcuate downstream curve is dimensioned to wrap around more than 180° of the second circular cross section.
4 . The BOAS segment of claim 1 , wherein the first rail further extends radially inward from the upstream end of the central portion; and
the second rail further extends radially inward from the downstream end of the central portion.
5 . The BOAS segment of claim 4 , further comprising a flexible insulation blanket formed of carbon/graphite felt disposed on an inside surface of the CMC sleeve.
6 . The BOAS segment of claim 5 , further comprising a metal leaf spring disposed between the first and second rails of the support component and the flexible insulation blanket to drive the flexible insulation blanket against the CMC sleeve.
7 . The BOAS segment of claim 6 , wherein the arcuate upstream curve is dimensioned to accommodate the flexible insulation blanket and an upstream end of the metal leaf spring disposed on the first circular cross section; and
the arcuate downstream curve is dimensioned to accommodate the flexible insulation blanket and a downstream end of the metal leaf spring disposed on the second circular cross section.
8 . A blade outer air seal (BOAS) segment of a gas turbine engine, comprising:
a support component extending circumferentially in an arc, the support component having a uniform axial cross section that includes:
a central portion extending axially from an upstream end to a downstream end;
a first support flange extending radially outward from the upstream end of the central portion;
a second support flange extending radially outward from the downstream end of the central portion;
a first rail extending axially from the upstream end of the central portion, the first rail terminating with a first circular cross section; and
a second rail extending axially from the downstream end of the central portion, the second rail terminating with a second circular cross section; and
a ceramic matrix composite (CMC) sleeve extending circumferentially in an arc, the CMC sleeve formed of a plurality of stacked plies to have a uniform thickness and having a uniform axial cross section that includes:
an arcuate upstream curve dimensioned to slide onto the first circular cross section;
an arcuate downstream curve dimensioned to slide onto the second circular cross section; and
an axial portion extending between the arcuate upstream curve and the arcuate downstream curve,
wherein the CMC sleeve is attached to the support component by circumferentially sliding onto the first and second rails,
wherein a diameter of the first circular cross section is larger than a thickness of a remainder of the first rail; and
a diameter of the second circular cross section is larger than a thickness of a remainder of the second rail.
9 . A blade outer air seal (BOAS) segment of a gas turbine engine, comprising:
a metal support component extending circumferentially in an arc, the metal support component formed of a Nickel (Ni) containing alloy or a Cobalt (Co) containing alloy, and having a uniform axial cross section that includes:
a central portion extending axially from an upstream end to a downstream end;
a first support flange extending radially outward from the upstream end of the central portion;
a second support flange extending radially outward from the downstream end of the central portion;
a first rail extending axially from the upstream end of the central portion, the first rail terminating with a first circular cross section having a diameter greater than a thickness of a remainder of the first rail; and
a second rail extending axially from the downstream end of the central portion, the second rail terminating with a second circular cross section having a diameter greater than a thickness of a remainder of the second rail;
a ceramic matrix composite (CMC) sleeve extending circumferentially in an arc, the CMC sleeve formed of a plurality of stacked plies to have a uniform thickness and having a uniform axial cross section that includes:
an arcuate upstream curve;
an arcuate downstream curve; and
an axial portion extending between the arcuate upstream curve and the arcuate downstream curve; and
a flexible insulation blanket formed of carbon/graphite felt disposed on an inside surface of the CMC sleeve,
wherein the CMC sleeve is attached to the support component by circumferentially sliding onto the first and second rails with the flexible insulation blanket disposed therebetween.
10 . The BOAS segment of claim 9 , further comprising a metal leaf spring disposed between the first and second rails of the metal support component and the flexible insulation blanket to drive the flexible insulation blanket against the CMC sleeve.
11 . The BOAS segment of claim 10 , wherein the arcuate upstream curve is dimensioned to accommodate the flexible insulation blanket and an upstream end of the metal leaf spring disposed on the first circular cross section and wrap around more than 180° of the first circular cross section; and
the arcuate downstream curve is dimensioned to accommodate the flexible insulation blanket and a downstream end of the metal leaf spring disposed on the second circular cross section and wrap around more than 180° of the second circular cross section.