CMC airfoil with circumventing cooling passage
An airfoil includes an airfoil section that defines a trailing edge region that includes a trailing edge. The airfoil section is formed of a ceramic matrix composite that includes core fiber plies and skin fiber plies. The core fiber plies define a radial tube that has a radiused end in the trailing edge region. The skin fiber plies wrap around the core fiber plies and a filler element in the trailing edge region is aft of the internal cavity and is sandwiched between the skin fiber plies on the pressure side and the skin fiber plies on the suction side. There is at least one cooling passage that includes a first, inlet orifice section that opens to the internal cavity at a location forward of the radiused end and that extends through the core fiber plies, and a second, outlet orifice section that extends through the trailing edge.
1 . An airfoil comprising:
an airfoil section defining pressure and suction sides, a leading edge, and a trailing edge region including a trailing edge, the airfoil section being formed of a ceramic matrix composite that includes fiber plies disposed in a ceramic matrix, the fiber plies including:
core fiber plies defining a radial tube that circumscribes an internal cavity, the radial tube having a radiused end in the trailing edge region, and
skin fiber plies defining an exterior of the airfoil section and wrapping around the core fiber plies from the pressure side of the trailing edge region, through the leading edge, and to the suction side of the trailing edge region;
a filler element in the trailing edge region aft of the internal cavity and sandwiched between the skin fiber plies on the pressure side and the skin fiber plies on the suction side; and
at least one cooling passage including:
a first, inlet orifice section opening to the internal cavity at a location forward of the radiused end and extending through the core fiber plies, wherein there is a number N of the core fiber plies each having a ply thickness t, and the location is forward of the radiused end by a distance D that is greater than the product of N, t, and a multiplier X that is from five to ten,
a second, outlet orifice section extending through the trailing edge, and
a third, intermediate section connecting the first and second sections, and the third section laterally bound by at least one of the skin plies.
2 . The airfoil as recited in claim 1 , wherein the third section is also laterally bound by the filler element.
3 . The airfoil as recited in claim 2 , wherein the filler element includes a filler core and a filler skin ply on the filler core, and the filler skin ply partially bounds the third section.
4 . The airfoil as recited in claim 2 , wherein the third section is bound by at least two of the skin plies.
5 . The airfoil as recited in claim 1 , wherein the location is toward the suction side of the core fiber plies.
6 . The airfoil as recited in claim 1 , wherein the at least one cooling passage includes multiple cooling passages, for a first portion of the multiple cooling passages the location is toward the suction side of the core fiber plies, and for a second portion of the multiple cooling passages the location is toward the pressure side of the core fiber plies.
7 . The airfoil as recited in claim 6 , wherein the multiple cooling passages each include a third, intermediate section connecting the first and second sections, the third section of the first portion of the multiple cooling passages extending adjacent the suction side between at least one of the skin plies and the filler element, and the third section of the second portion of the multiple cooling passages extending adjacent the pressure side between at least one of the skin plies and the filler element.
8 . The airfoil as recited in claim 1 , wherein an inner surface of the at least one of the skin plies bounds the third section, the inner surface facing toward the core fiber plies.
9 . The airfoil as recited in claim 8 , wherein the at least one cooling passage is a single cooling passage, the first inlet orifice section is a single inlet orifice, and the second outlet orifice section is a single outlet orifice.
10 . A gas turbine engine comprising:
a compressor section;
a combustor in fluid communication with the compressor section; and
a turbine section in fluid communication with the combustor, the turbine section having airfoils each including:
an airfoil section defining pressure and suction sides, a leading edge, and a trailing edge region including a trailing edge, the airfoil section being formed of a ceramic matrix composite that includes fiber plies disposed in a ceramic matrix, the fiber plies including:
core fiber plies defining a radial tube that circumscribes an internal cavity, the radial tube having a radiused end in the trailing edge region, and
skin fiber plies defining an exterior of the airfoil section and wrapping around the core fiber plies from the pressure side of the trailing edge region, through the leading edge, and to the suction side of the trailing edge region;
a filler element in the trailing edge region aft of the internal cavity and sandwiched between the skin fiber plies on the pressure side and the skin fiber plies on the suction side; and
at least one cooling passage including:
a first, inlet orifice section opening to the internal cavity at a location forward of the radiused end and extending through the core fiber plies, wherein there is a number N of the core fiber plies each having a ply thickness t, and the location is forward of the radiused end by a distance D that is greater than the product of N, t, and a multiplier X that is from five to ten,
a second, outlet orifice section extending through the trailing edge, and
a third, intermediate section connecting the first and second sections, and the third section laterally bound by at least two of the skin plies.
11 . The gas turbine engine as recited in claim 10 , wherein the location is toward the suction side of the core fiber plies.
12 . The gas turbine engine as recited in claim 10 , wherein the at least one cooling passage includes multiple cooling passages, for a first portion of the multiple cooling passages the location is toward the suction side of the core fiber plies, and for a second portion of the multiple cooling passages the location is toward the pressure side of the core fiber plies.
13 . The gas turbine engine as recited in claim 12 , wherein the multiple cooling passages each include a third, intermediate section connecting the first and second sections, the third section of the first portion of the multiple cooling passages extending adjacent the suction side between at least one of the skin plies and the filler element, and the third section of the second portion of the multiple cooling passages extending adjacent the pressure side between at least one of the skin plies and the filler element.
14 . A method of fabricating an airfoil that has an airfoil section defining pressure and suction sides, a leading edge, and a trailing edge region including a trailing edge, the method comprising:
forming a fiber preform by:
laying-up core fiber plies to form a radial tube that circumscribes an internal cavity, the radial tube having a radiused end in the trailing edge region;
laying-up skin fiber plies to wrap around the core fiber plies to form an exterior of the airfoil section, the skin fiber plies wrap from the pressure side of the trailing edge region, through the leading edge, and to the suction side of the trailing edge region;
arranging a filler element in the trailing edge region aft of the internal cavity and sandwiched between the skin fiber plies on the pressure side and the skin fiber plies on the suction side;
at least one cooling passage being formed in the airfoil section by a first, inlet orifice section that extends through the core fiber plies and that opens to the internal cavity at a location forward of the radiused end, wherein there is a number N of the core fiber plies each having a ply thickness t, and the location is forward of the radiused end by a distance D that is greater than the product of N, t, and a multiplier X that is from five to ten, a second, outlet orifice section that extends through the trailing edge, and a third, intermediate section connecting the first and second sections, the third section laterally bound by at least one of the skin plies; and
densifying the fiber preform with a ceramic matrix to form a ceramic matrix composite.
15 . The method as recited in claim 14 , wherein, prior to the densifying, the core fiber plies and the skin fiber plies contain no ceramic matrix.