Vane Arc Segment With Spar Pin Fairing for Cooling Airflow
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Solution Overview
Problem
Implementing ceramic matrix composite (CMC) materials in gas turbine engine airfoils poses unique challenges due to their integration and compatibility with existing structural components.
Innovation Solution
A spar with a pin fairing is integrated into the vane arc segment, featuring a bearing surface and a wear-resistant coating, which includes a pin fairing that seals the pin from the internal passage and guides cooling air flow efficiently, while being formed from high-temperature resistant materials like single crystal metal alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC materials are used in airfoils to extend temperature capability, then temperature resistance is improved, but integration compatibility with existing structural components deteriorates
Solution Approach 1:
A transition layer is introduced between the CMC airfoil and the metallic spar to serve as an intermediary component. This transition layer includes a thermal barrier coating that bridges the thermal and mechanical property gaps between CMC and metal materials, enabling compatible integration while maintaining the high temperature resistance of CMC materials
Solution Approach 2:
The airfoil structure employs a composite material system combining CMC materials with metallic components (spar and transition layer). This composite approach allows each material to contribute its advantageous properties - CMC for high temperature resistance and metal for structural strength and flexibility in integration
2Reliability
If pin fairing is added to seal pin from internal passage, then leakage prevention is improved, but device complexity increases
Solution Approach 1:
The pin fairing is merged with the existing spar structure rather than being a separate component. The fairing is integrated into the spar's geometry, sealing the pin from the internal passage while maintaining a streamlined external surface. This integration prevents leakage without significantly increasing overall device complexity
Solution Approach 2:
The pin fairing serves multiple functions simultaneously: it seals the pin from the internal passage to prevent leakage, provides a streamlined aerodynamic surface, and maintains structural integrity. This multi-functionality achieves reliable sealing without adding unnecessary complexity
3Duration of action of stationary object
If wear-resistant coating is applied to bearing surface, then durability is improved, but manufacturing complexity increases
Solution Approach 1:
The bearing surface undergoes parameter changes through the application of wear-resistant coating, which modifies the surface properties (hardness, friction characteristics) to enhance durability. The coating process changes the surface parameters without fundamentally altering the bulk material or requiring complex manufacturing steps
4Use of energy by moving object
If pin fairing guides cooling air flow efficiently, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The pin fairing incorporates curved and streamlined geometries that guide cooling air flow efficiently around the pin. The curved surfaces promote smooth airflow transitions and reduce turbulence, enhancing cooling efficiency while the fairing remains integrated with the spar structure to limit complexity increases
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the structural integrity and cooling efficiency of CMC airfoils by preventing leakage and reducing pressure loss, thereby extending the temperature capability and lifetime of the airfoils.
Implementation Method 1
the bearing surface includes a wear-resistant coating such as a hardcoat
Implementation Method 2
the pin fairing seals the pin from the internal passage
Implementation Method 3
the pin fairing includes a bearing surface in contact with the pin
Data Source
Figure 1
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AI summary
A vane arc segment (60) includes an airfoil fairing (62) that has first and second fairing platforms (66, 68) and a hollow airfoil section (64). A spar (72) has a spar platform (72a) adjacent the first fairing platform (66) and a hollow spar leg (72b) that extends from the spar platform (72a) and through the hollow airfoil section (64). The hollow spar leg (72b) has an internal passage (72c) for receiving cool air there through, a clevis mount (76), and a pin fairing (86). The clevis mount (76) is distal from the spar platform (72a) and protrudes from the second fairing platform (68). The clevis mount (76) includes first and second prongs (84a, 84b) with aligned holes (77). A pin (82) extends through the aligned holes (77). The pin fairing (86) extends over the pin (82) between the first and second prongs (84a, 84b) for guiding the cooling air around the pin (82). There is a support platform (78) adjacent the second fairing platform (68). The pin (82) locks the support platform (78) to the spar leg (72b).