Internally cooled brush seal backing plate and method

A cooled brush seal for use with a ceramic matrix composite (CMC) blade outer air seal (BOAS) of a gas turbine engine, the CMC BOAS formed of a plurality of segments having a hot side configured for exposure to a hot gas path of the gas turbine engine and an opposing side having a seal land and a cavity for feeding a cooling flow to at least one film cooling hole of the CMC BOAS, the cooled brush seal comprising:

• an outer diameter (OD) backing plate;
• an inner diameter (ID) backing plate;
• a plurality of brush seal bristles sandwiched between the OD backing plate and the ID backing plate;
• a first hole for each segment forming a first passage extending through the OD backing plate, the brush seal bristles, and the ID backing plate;
• and
• a cover plate attached by being welded or brazed to an inner surface of the ID backing plate and including a second hole for each segment circumferentially offset from the first hole and forming a second passage into the cavity of the segment,
• wherein one of the ID backing plate and the cover plate includes a serpentine channel such that the ID backing plate and the cover plate form a circumferentially-extending serpentine cooling passage for each segment extending between the first hole and the second hole.

A method of cooling a brush seal for use with ceramic matrix composite (CMC) component of a gas turbine engine, the CMC component having a hot side configured for exposure to a hot gas path of the gas turbine engine and an opposing side having a seal land and a cavity for feeding a cooling flow to at least one film cooling hole of the CMC component, the method comprising:

• joining an outer diameter (OD) backing plate, an inner diameter (ID) backing plate, and a plurality of brush seal bristles sandwiched between the OD backing plate and the ID backing plate;
• forming a first passage with a first hole extending through the OD backing plate, the brush seal bristles, and the ID backing plate;
• attaching a cover plate to an inner surface of the ID backing plate, the cover plate including a second hole circumferentially offset from the first hole and forming a second passage into the cavity of the CMC component, wherein the ID backing plate and the cover plate form a circumferentially-extending cooling passage segment extending between the first hole and the second hole;
• and
• feeding a cooling flow through the first hole into the cooling passage segment and through the second hole into the cavity to supply the at least one film cooling hole.