Cooling arrangement including alternating pedestals for gas turbine engine components

A gas turbine engine comprising:

• an array of blades and an array of vanes spaced axially from the array of blades in a gas path, the array of blades are rotatable in the gas path, and an array of blade outer air seals (BOAS) arranged about the array of blades to bound the gas path;
• and
• wherein at least one of the array of blades, the array of vanes and the array of BOAS comprises:
• an external wall between an internal wall surface and an external wall surface, the internal wall surface bounding an internal cavity;
• wherein at least one pair of adjacent bounding pedestals are established in a thickness of the external wall, the adjacent bounding pedestals extend from the external wall surface to establish a cooling passage, a common pedestal is situated between the adjacent bounding pedestals to establish a first branched section and a second branched section that join together at a merged section, the merged section establishes an outlet along the external wall surface between the adjacent bounding pedestals which extend to the outlet, the common pedestal is spaced apart from the outlet, and the adjacent bounding pedestals and the common pedestal establish first and second throats along the respective first and second branched sections and establish respective diffusion zones between the respective first and second throats and the merged section;
• one or more coatings extending into the outlet to establish a coated outlet region of the merged section of the cooling passage;
• and
• wherein the first and second throats establish a local minimum cross-sectional area along the respective first and second branched sections, a local minimum cross-sectional area of the cooling passage along the coated outlet region divided by a total of the local minimum cross-sectional areas of the first and second throats establishes a coated area ratio, and the coated area ratio is greater than or equal to 0.8, and is less than or equal to 1.5.

A method of fabricating a gas turbine engine component comprising:

• establishing an internal cavity bounded by an external wall;
• establishing a cooling passage between adjacent bounding pedestals in the external wall, wherein the adjacent bounding pedestals extend from an external wall surface of the external wall to establish an outlet of the cooling passage, a common pedestal is situated between the adjacent bounding pedestals to establish a first branched section and a second branched section of the cooling passage that join together at a merged section of the cooling passage, the merged section interconnects the first and second branched sections and the outlet, and the common pedestal is spaced apart from the outlet, first and second inlets to the respective first and second branched sections are established between the adjacent bounding pedestals and the common pedestal, and the first and second inlets are coupled to the internal cavity;
• wherein the adjacent bounding pedestals and the common pedestal are dimensioned such that first and second throats are established along the respective first and second branched sections and such that the first and second branched sections expand towards the outlet to establish respective diffusion zones, the diffusion zones interconnecting the merged section and the respective first and second throats;
• forming one or more coatings along the external wall surface and into the outlet to establish a coated outlet region of the cooling passage;
• and
• wherein the first and second throats establish a local minimum cross-sectional area along the respective first and second branched sections, a local minimum cross-sectional area of the cooling passage along the coated outlet region divided by a total of the local minimum cross-sectional areas of the first and second throats establishes a coated area ratio, and the coated area ratio is greater than or equal to 0.8, and is less than or equal to 1.5.