EP4613974A1

EP4613974A1 - Process of forming a capillary airfoil design for active heating and cooling, and solid airfoil

Info

Publication number: EP4613974A1
Application number: EP25161699.1A
Authority: EP
Inventors: David E. Bitter; Paul Owen Kelson; Matthew Michael Massaro; Lucas O. McCaslin; Bryan A. L. Hofferd; William John Oldach; Ramons A. Reba
Original assignee: RTX Corp
Current assignee: RTX Corp
Priority date: 2024-03-05
Filing date: 2025-03-04
Publication date: 2025-09-10

Abstract

A solid airfoil assembly (60) comprises:
- a solid airfoil body (62) including a leading edge (70) and a trailing edge (72), a suction side (74) opposite a pressure side (72), a first trunnion (78) proximate the leading edge opposite a second trunnion (80) proximate the leading edge;
- a faceplate cavity (88) formed within the solid airfoil body;
- an inlet port (82) formed through the first trunnion;
- a major airflow passage (90) formed within the faceplate cavity, the major airflow passage being in fluid communication with the inlet port;
- a minor airflow passage (92) formed within the solid airfoil body within the faceplate cavity, the minor airflow passage being in fluid communication with the major airflow passage;
- an exit port (94) in fluid communication with the minor airflow passage, the exit port being in fluid communication with the inlet port; and
- a cover (64) attached to the faceplate cavity enclosing each of the major airflow passage and the minor airflow passage.

Description

BACKGROUND

The present disclosure is directed to an airfoil with a solid body that is machined to form a pocket with a series of air capillaries fluidly coupled to a passage formed in a trunnion of the airfoil. A cover is attached to seal the pocket and form a desired vane geometry.
Hollow vanes are typically utilized to enable air, either hot or cold, to flow through the part to achieve a desired thermal effect. Historically, hollow vanes have been manufactured by casting the external airfoil shape with cores located internally within the mold. This method results in a hollow cavity within the cast part, however, castings, from both a process capability and supplier willingness perspectives, are not capable of meeting the dimensional and material requirements as demanded by the engine operating environment.

SUMMARY

In accordance with the present disclosure, there is provided a process of forming a capillary airfoil design for active heating and cooling comprising forming a solid airfoil body, the solid airfoil body including a leading edge and a trailing edge opposite the leading edge, the solid airfoil body including a suction side opposite a pressure side, the solid airfoil body including a first trunnion proximate the leading edge opposite a second trunnion proximate the leading edge; forming a faceplate cavity within the solid airfoil body; forming an inlet port through the first trunnion; forming a major airflow passage in the solid airfoil body within the faceplate cavity, the major airflow passage being in fluid communication with the inlet port; forming a minor airflow passage within the solid airfoil body within the faceplate cavity, the minor airflow passage being in fluid communication with the major airflow passage; forming an exit port in fluid communication with the minor airflow passage, the exit port being in fluid communication with the inlet port; forming a cover, the cover being configured to attach to the faceplate cavity to enclose each of the major airflow passage and the minor airflow passage; and attaching the cover to the solid airfoil body.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising forming the airflow passages in a shape selected from the group consisting of channels, furrows, cavities and the like.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the minor airflow passage is configured as multiple cooling channels that allow for cooling fluid to flow through the solid airfoil body.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising forming an airfoil from the combination of the solid body bonded together with the cover.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising forming a single walled structure having contoured surfaces.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the solid airfoil body comprises a monolithic body.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising forming the major airflow passage and the minor airflow passage by varying of a cross-sectional area across a chord and span of the solid airfoil body to balance an airflow through the major airflow passage and the minor airflow passage to create uniform heat transfer.
In accordance with the present disclosure, there is provided a solid airfoil assembly comprising a solid airfoil body including a leading edge and a trailing edge opposite the leading edge, the solid airfoil body including a suction side opposite a pressure side, the solid airfoil body including a first trunnion proximate the leading edge opposite a second trunnion proximate the leading edge; a faceplate cavity formed within the solid airfoil body; an inlet port formed through the first trunnion; a major airflow passage formed in the solid airfoil body within the faceplate cavity, the major airflow passage being in fluid communication with the inlet port; a minor airflow passage formed within the solid airfoil body within the faceplate cavity, the minor airflow passage being in fluid communication with the major airflow passage; an exit port in fluid communication with the minor airflow passage, the exit port being in fluid communication with the inlet port; and a cover attached to the faceplate cavity enclosing each of the major airflow passage and the minor airflow passage.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the airflow passages are in a shape selected from the group consisting of channels, furrows, cavities and the like.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include an airfoil is formed from the combination of the solid body bonded together with the cover.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the minor airflow passage is configured as multiple cooling channels that allow for cooling fluid to flow through the solid airfoil body.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the solid airfoil body comprises a single walled structure having contoured surfaces.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the solid airfoil body comprises a monolithic body.
In accordance with the present disclosure, there is provided a process for joining a cover to a solid airfoil body comprising forming a solid airfoil body, the solid airfoil body including a leading edge and a trailing edge opposite the leading edge, the solid airfoil body including a suction side opposite a pressure side, the solid airfoil body including a first trunnion proximate the leading edge opposite a second trunnion proximate the leading edge; forming a faceplate cavity within the solid airfoil body; forming an inlet port through the first trunnion; forming a major airflow passage in the solid airfoil body within the faceplate cavity, the major airflow passage being in fluid communication with the inlet port; forming a minor airflow passage within the solid airfoil body within the faceplate cavity, the minor airflow passage being in fluid communication with the major airflow passage; forming an exit port in fluid communication with the minor airflow passage, the exit port being in fluid communication with the inlet port; forming a cover, the cover being configured to attach to the faceplate cavity to enclose each of the major airflow passage and the minor airflow passage; and attaching the cover to the solid airfoil body.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising removing material from the solid airfoil body with predetermined faceplate cavity dimensions; and installing the cover within the faceplate cavity.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising removing material from the solid airfoil body from at least one of the suction side and the pressure side of the solid airfoil body form the faceplate cavity.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising extending the major airflow passage substantially spanwise along a length of the solid airfoil body between the first trunnion and the second trunnion.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising extending the minor airflow passages chordwise from the leading edge side to the trailing edge side of the solid airfoil body.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising closing the major airflow passage and the minor airflow passage with the cover; and forming a three-dimensional flow passage with walls configured to surround air flowing within the major airflow passage and minor airflow passage.
A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising forming the cover from a plate stock material compatible with the solid airfoil body.
Other details of the capillary airfoil design for active heating and cooling are set forth in the following detailed description and the accompanying drawings wherein like reference numerals depict like elements.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a cross section view of an exemplary gas turbine engine.
Fig. 2 is a schematic representation of an exemplary solid airfoil and cover.
Fig. 3 is a schematic representation of an exemplary solid airfoil assembly.
Fig. 4 is a schematic representation of a cross-sectional view (cut A) of the exemplary solid airfoil assembly of Fig. 3.
Fig. 5 is a schematic representation of a forward looking aft cross-sectional view (cut B) of the exemplary solid airfoil assembly of Fig. 3.
Fig. 6 is a schematic representation of an exemplary solid airfoil.
Fig. 7 is a schematic representation of an exemplary solid airfoil with material removed.
Fig. 8 is a schematic representation of a cross-sectional view (cut C) of the exemplary solid airfoil of Fig. 7.
Fig. 9 is a schematic representation of an exemplary solid airfoil assembly.
Fig. 10 is a schematic representation of a cross-sectional view (cut D) and (cut E) of the exemplary solid airfoil assembly of Fig. 9.
Fig. 11 is a process map.

DETAILED DESCRIPTION

Figure 1 schematically illustrates a gas turbine engine 20. The gas turbine engine 20 is disclosed herein as a two-spool turbofan that generally incorporates a fan section 22, a compressor section 24, a combustor section 26 and a turbine section 28. The fan section 22 may include a single-stage fan 42 having a plurality of fan blades 43. The fan blades 43 may have a fixed stagger angle or may have a variable pitch to direct incoming airflow from an engine inlet. The fan 42 drives air along a bypass flow path B in a bypass duct 13 defined within a housing 15 such as a fan case or nacelle, and also drives air along a core flow path C for compression and communication into the combustor section 26 then expansion through the turbine section 28. A splitter 29 aft of the fan 42 divides the air between the bypass flow path B and the core flow path C. The housing 15 may surround the fan 42 to establish an outer diameter of the bypass duct 13. The splitter 29 may establish an inner diameter of the bypass duct 13. Although depicted as a two-spool turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with two-spool turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures.
The exemplary engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine central longitudinal axis A relative to an engine static structure 36 via several bearing systems 38. It should be understood that various bearing systems 38 at various locations may alternatively or additionally be provided, and the location of bearing systems 38 may be varied as appropriate to the application.
The low speed spool 30 generally includes an inner shaft 40 that interconnects, a first (or low) pressure compressor 44 and a first (or low) pressure turbine 46. The inner shaft 40 is connected to the fan 42 through a speed change mechanism, which in the exemplary gas turbine engine 20 is illustrated as a geared architecture 48 to drive the fan 42 at a lower speed than the low speed spool 30. The inner shaft 40 may interconnect the low pressure compressor 44 and low pressure turbine 46 such that the low pressure compressor 44 and low pressure turbine 46 are rotatable at a common speed and in a common direction. In other embodiments, the low pressure turbine 46 drives both the fan 42 and low pressure compressor 44 through the geared architecture 48 such that the fan 42 and low pressure compressor 44 are rotatable at a common speed. Although this application discloses geared architecture 48, its teaching may benefit direct drive engines having no geared architecture. The high speed spool 32 includes an outer shaft 50 that interconnects a second (or high) pressure compressor 52 and a second (or high) pressure turbine 54. A combustor 56 is arranged in the exemplary gas turbine 20 between the high pressure compressor 52 and the high pressure turbine 54. A mid-turbine frame 57 of the engine static structure 36 may be arranged generally between the high pressure turbine 54 and the low pressure turbine 46. The mid-turbine frame 57 further supports bearing systems 38 in the turbine section 28. The inner shaft 40 and the outer shaft 50 are concentric and rotate via bearing systems 38 about the engine central longitudinal axis A which is collinear with their longitudinal axes.
Airflow in the core flow path C is compressed by the low pressure compressor 44 then the high pressure compressor 52, mixed and burned with fuel in the combustor 56, then expanded through the high pressure turbine 54 and low pressure turbine 46. The mid-turbine frame 57 includes airfoils 59 which are in the core flow path C. The turbines 46, 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion. It will be appreciated that each of the positions of the fan section 22, compressor section 24, combustor section 26, turbine section 28, and fan drive gear system 48 may be varied. For example, gear system 48 may be located aft of the low pressure compressor, or aft of the combustor section 26 or even aft of turbine section 28, and fan 42 may be positioned forward or aft of the location of gear system 48.
The low pressure compressor 44, high pressure compressor 52, high pressure turbine 54 and low pressure turbine 46 each include one or more stages having a row of rotatable airfoils. Each stage may include a row of static vanes adjacent the rotatable airfoils. The rotatable airfoils and vanes are schematically indicated at 47 and 49.
Referring also to Fig. 2 and Fig. 3 showing an exemplary solid airfoil assembly 60. The solid airfoil assembly 60 includes a body 62 that can be a single piece design, being completely integral and monolithic. The solid airfoil assembly 60 includes a faceplate cover 64 that is attachable to the body 62. The body 62 and cover 64 are combined to form an airfoil 66. The airfoil 66 can be used as a vane 68. The airfoil 66 includes a leading edge 70 and a trailing edge 72 opposite the leading edge 70. The airfoil 66 includes a suction side 74 and a pressure side 76 opposite the suction side 74. It is contemplated that the solid airfoil assembly 60 can also be configured as other single walled structures having contoured surfaces, such as a turbine blade. The solid airfoil assembly 60 can include a three dimensionally contoured shape. The three-dimensional contoured surface can refer to a surface defined by an X, Y, and Z axis. The three-dimensional contoured surface can vary from point to point to include surface variation of X, Y and Z coordinates.
Referring also to Fig. 4 and Fig. 5, the solid airfoil assembly 60 can include a first trunnion 78 and a second trunnion 80 opposite the first trunnion 78. The trunnions 78, 80 can be configured as a cylindrical protrusion used as a mounting or pivoting point for the vane 68. The first trunnion 78 can include an inlet port 82. The inlet port 82 can be a hollow portion configured to fluidly couple air 84 to the solid airfoil assembly 60 from an air source 86 as seen in Fig. 3.
A faceplate cavity 88 can be formed into the body 62. The faceplate cavity 88 can be formed by removing material from the body 62 shaped as a pocket to a predetermined size that matches the dimensions of the cover 64, such that the cover 64 can fit within the faceplate cavity 88. The faceplate cavity 88 predetermined size can be responsive to the size of the cover 64, such that the cover 64 when nested within the faceplate cavity 88, completes the airfoil 66 shape. The predetermined size can also be related to the location of cooling passages 90, 92 needed for cooling the body 62.
A major airflow passage 90 can be formed in the body 62 fluidly coupling the inlet port 82 to a minor airflow passage 92. There can be multiple minor airflow passages 92 formed into the body 62 that branch off the major airflow passage 90. The minor airflow passages 92 can be capillary sized passages relative to the major airflow passage 90. The minor airflow passages 92 extend from the major airflow passage 90 along the body 62 generally along a chordwise direction from the leading edge 70 to the trailing edge 72. The minor airflow passages 92 terminate proximate the trailing edge 72 allowing the air 84 to exit the airfoil 66 to atmosphere through exit ports 94.
It is contemplated that the airflow passages 90, 92 can have surface features that enhance fluid flow and heat transfer properties between the surfaces of the airflow passages 90, 92 and the air 84.
The major airflow passage 90 and minor airflow passages 92 can be formed by removing material from the body 62. The faceplate cavity 88 allows access for machinery/cutting tools to form the airflow passages 90, 92 in the body 62. It is contemplated that chemical material removal processes can be employed to form the airflow passages 90, 92. The airflow passages 90, 92 can be shaped as channels, furrows, cavities and the like, having a length, width and depth dimensions.
The air 84 flowing into the inlet port 82 through the first trunnion 78 and into the major airflow passage 90 can have relatively higher static/dynamic pressure P1 than the air 84 flowing in the major airflow passage 90 proximate the second trunnion 80 well downstream of the first trunnion 78 at a relatively lower static/dynamic pressure P2. The fluid mechanics of the air flowing proximate the first trunnion 78 through the major airflow passage 90 can bias the air 84 to flow into the minor airflow passages 92 proximate that region and starve some of the minor airflow passages 92 more distal from the first trunnion 78. The minor airflow passages 92 can be formed with varying cross-sectional area to compensate for the pressure differentials and fluid flow properties of the airflow passages 90, 92 to provide more even supply of air 84 throughout the solid airfoil assembly 60. The airflow passages 90, 92 can be tuned by variation of the cross-sectional area across the chord and span of the vane 68. The major airflow passage 90 and the minor airflow passage 92 can be tuned by varying the cross-sectional area across a chord and span of the solid airfoil body 62 to balance airflow through the major airflow passage 90 and the minor airflow passage 92 to create uniform heat transfer.
Referring also to Fig. 6 through Fig. 11, the process 100 of forming the exemplary solid airfoil assembly 60 can be discussed. Fig, 6 shows a solid body 62. At step 110, the solid body 62 can be formed. The solid body 62 includes the appropriate shape and dimensions for a vane 68 or other end use. A variety of processes can be employed to create the solid body 62 of the solid airfoil assembly 60.
Referring to Fig. 7 and Fig. 8, at step 112 the faceplate cavity 88 can be formed. Material is removed from the body 62 in the predetermined dimensions to allow for a tight fit installation of the cover 64. In the exemplary embodiment shown, both the suction side 74 and the pressure side 76 of the body 62 can have the material removed to form the faceplate cavity 88. In another embodiment, only a single side may have the material removed.
The next step 114 includes forming the inlet port 82 through the first trunnion 78. The first trunnion 78 material is drilled out to form the inlet port 82 as shown at Fig. 9 and Fig. 10. A hole can be drilled from the exterior of the first trunnion 78 into the body 62 of the solid airfoil 60.
The next step 116 includes forming the major airflow passage 90. The major airflow passage 90 can be coupled with the inlet port 82 such that there is fluid communication between the inlet port 82 and the major airflow passage 90. The major airflow passage 90 can extend from the inlet port 82 proximate the first trunnion 78 substantially proximate the leading edge 70 proximate to the second trunnion 80. The major airflow passage 90 can extend substantially spanwise along the length of the body 62 between the first trunnion 78 and second trunnion 80. It is contemplated that the length dimension L, width dimension w and depth dimension d can be varied to tailor the flow properties of the air 84 flowing in the major airflow passage 90.
The next step 118 includes forming the minor airflow passages 92. The minor airflow passages 92 can be coupled along the major airflow passage 90 spanwise and extend chordwise between the leading edge 70 side and the trailing edge 72 side of the body 62. The minor airflow passage 92 can terminate at the exit port 94 proximate the trailing edge 72. The material of the body 62 can be removed forming the furrow, slot, channel, and the like shape of the minor airflow passage 90. The length L of the minor airflow passage 92 can be responsive to the chordwise dimension of the airfoil 66. It is contemplated that the length dimension L, width dimension w and depth dimension d can be varied to tailor the flow properties of the air 84 flowing in the minor airflow passage 92.
The next step 120 includes forming the cover 64. The cover 64 can be formed from plate stock materials compatible with the solid body 62. The cover 64 can be dimensioned to fit within the faceplate cavity 88. The cover 64 can close in the open channels of the major airflow passage 90 and the minor airflow passages 92 to transform an open channel into a three-dimensional flow passage 90, 92 with walls that completely surround the air 84 that flows within the airflow passages 90, 92. The cover 64 material can be stamped or machined to the proper dimensions.
The next step 122 includes attaching the cover 64 to the body 62. The cover 64 is bonded to the body 62. The cover 64 can be set in place and be flush with an outer surface 96 of the airfoil 66 to form smooth aerodynamic flow surfaces for the airfoil 66. A braze joint can be utilized to secure the cover 64 to the body 62.
A technical advantage of the capillary airfoil design for active heating and cooling can include enabling a process for fabricating an airfoil with active air cooling/heating.
Another technical advantage of the capillary airfoil design for active heating and cooling can include the selection of a manufacturing method that meets the geometric requirements of the hardware while reducing the metallurgical shortfalls imposed by when casting hollow vanes.
Another technical advantage of the capillary airfoil design for active heating and cooling can include allowing for the air to locally heat the surfaces.
Another technical advantage of the capillary airfoil design for active heating and cooling can include solving significant structural problems and airflow requirements of previous designs.
Another technical advantage of the capillary airfoil design for active heating and cooling can include direct machining access within the internal passageways of the vane.
Another technical advantage of the capillary airfoil design for active heating and cooling can include capacity to optimize ice protection air flow.
Another technical advantage of the capillary airfoil design for active heating and cooling can include the ability to perform low-cost visual surface inspections of the open body and cover plate for voids or surface flaws, such as fluorescent penetrant inspection (FPI), before the pieces are brazed together.
There has been provided a capillary airfoil design for active heating and cooling. While the capillary airfoil design for active heating and cooling has been described in the context of specific embodiments thereof, other unforeseen alternatives, modifications, and variations may become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations which fall within the broad scope of the appended claims.

Claims

A process of forming a capillary airfoil design for active heating and cooling comprising:
forming a solid airfoil body, the solid airfoil body including a leading edge and a trailing edge opposite the leading edge, the solid airfoil body including a suction side opposite a pressure side, the solid airfoil body including a first trunnion proximate the leading edge opposite a second trunnion proximate the leading edge;

forming a faceplate cavity within the solid airfoil body;

forming an inlet port through the first trunnion;

forming a major airflow passage in the solid airfoil body within the faceplate cavity, the major airflow passage being in fluid communication with the inlet port;

forming a minor airflow passage within the solid airfoil body within the faceplate cavity, the minor airflow passage being in fluid communication with the major airflow passage;

forming an exit port in fluid communication with the minor airflow passage, the exit port being in fluid communication with the inlet port;

forming a cover, the cover being configured to attach to the faceplate cavity to enclose each of the major airflow passage and the minor airflow passage; and

attaching the cover to the solid airfoil body.
The process according to claim 1, further comprising:
forming the airflow passages in a shape selected from the group consisting of channels, furrows, cavities and the like.
The process according to claim 1 or 2, wherein the minor airflow passage is configured as multiple cooling channels that allow for cooling fluid to flow through the solid airfoil body.
The process according to any of the preceding claims, further comprising:
forming an airfoil from the combination of the solid body bonded together with the cover;
and/or

forming a single walled structure having contoured surfaces.
The process according to any of the preceding claims, wherein the solid airfoil body comprises a monolithic body.
The process according to any of the preceding claims, further comprising:
forming the major airflow passage and the minor airflow passage by varying of a cross-sectional area across a chord and span of the solid airfoil body to balance an airflow through the major airflow passage and the minor airflow passage to create uniform heat transfer.
The process according to any of the preceding claims, further comprising:
removing material from the solid airfoil body with predetermined faceplate cavity dimensions and installing the cover within the faceplate cavity;
and/or

removing material from the solid airfoil body from at least one of the suction side and the pressure side of the solid airfoil body to form the faceplate cavity.
The process according to any of the preceding claims, further comprising:
extending the major airflow passage substantially spanwise along a length of the solid airfoil body between the first trunnion and the second trunnion;
and/or

extending the minor airflow passages chordwise from the leading edge side to the trailing edge side of the solid airfoil body.
The process according to any of the preceding claims, further comprising:
closing the major airflow passage and the minor airflow passage with the cover; and

forming a three-dimensional flow passage with walls configured to surround air flowing within the major airflow passage and minor airflow passage.
The process according to any of the preceding claims, further comprising:
forming the cover from a plate stock material compatible with the solid airfoil body.
A solid airfoil assembly comprising:
a solid airfoil body including a leading edge and a trailing edge opposite the leading edge, the solid airfoil body including a suction side opposite a pressure side, the solid airfoil body including a first trunnion proximate the leading edge opposite a second trunnion proximate the leading edge;

a faceplate cavity formed within the solid airfoil body;

an inlet port formed through the first trunnion;

a major airflow passage formed in the solid airfoil body within the faceplate cavity, the major airflow passage being in fluid communication with the inlet port;

a minor airflow passage formed within the solid airfoil body within the faceplate cavity, the minor airflow passage being in fluid communication with the major airflow passage;

an exit port in fluid communication with the minor airflow passage, the exit port being in fluid communication with the inlet port; and

a cover attached to the faceplate cavity enclosing each of the major airflow passage and the minor airflow passage.
The solid airfoil assembly according to claim 11, wherein the airflow passages are in a shape selected from the group consisting of channels, furrows, cavities and the like.
The solid airfoil assembly according to claim 11 or 12, wherein an airfoil is formed from the combination of the solid body bonded together with the cover.
The solid airfoil assembly according to any of claims 11 to 13, wherein the minor airflow passage is configured as multiple cooling channels that allow for cooling fluid to flow through the solid airfoil body.
The solid airfoil assembly according to any of claims 11 to 14,
wherein the solid airfoil body comprises a single walled structure having contoured surfaces;
and/or

wherein the solid airfoil body comprises a monolithic body.