CMC Vane Arc Segment Insulation for Thermal Stress Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Implementing ceramic matrix composite (CMC) materials in gas turbine engine airfoils is challenging due to their susceptibility to thermal distress from thermal gradients and stresses, which can be exacerbated by cooling methods intended to improve durability.
Innovation Solution
A vane arc segment design featuring a ceramic airfoil piece supported by metallic hardware through a thermal insulation element, which circumscribes the airfoil's radial flange and limits thermal conductance, and a machining method to achieve a low-tolerance fit between the flange and insulation element to reduce play and thermal stress.
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 susceptibility to thermal distress from thermal gradients and stresses increases
Solution Approach 1:
A thermal insulation element is introduced as an intermediary component between the CMC airfoil piece and the metallic support hardware. This element acts as a thermal barrier that reduces thermal conductance, protecting the CMC material from thermal gradients and thermal shock while allowing the airfoil to operate at higher temperatures.
Solution Approach 2:
The thermal insulation element provides beforehand cushioning by absorbing and mitigating thermal stress before it reaches the CMC airfoil piece. The element is positioned in advance to prevent thermal distress, creating a protective buffer zone that reduces thermal gradients during operation.
2Reliability
If cooling methods are applied to improve CMC durability, then thermal stress resistance is improved, but thermal gradients are exacerbated
Solution Approach 1:
The thermal insulation element serves as a mediator that decouples the cooling effect from the CMC airfoil piece. By positioning the insulation element between the airfoil and the cooling hardware, the system can apply cooling methods to improve durability while the insulation element prevents excessive thermal gradients from developing in the CMC material.
3Strength
If play is reduced between airfoil piece and support hardware, then structural integrity is improved, but thermal stress increases
Solution Approach 1:
The thermal insulation element acts as a compliant intermediary that allows for reduced play and improved structural integrity while accommodating thermal expansion and contraction. The element's material properties enable it to absorb thermal stress while maintaining mechanical contact, thus improving structural integrity without excessively increasing thermal stress on the CMC airfoil piece.
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
The solution effectively reduces thermal stress and play in the vane arc segment, enhancing the durability and performance of CMC airfoils by minimizing thermal gradients and maintaining structural integrity under high-temperature conditions.
Implementation Method 1
a thermal insulation element, which circumscribes the airfoil's radial flange and limits thermal conductance
Data Source
AI summary
A vane arc segment includes an airfoil piece that defines first and second platforms and an airfoil section that extends between the first and second platforms. The first platform defines a gaspath side, a non-gaspath side, and a first platform radial flange that projects from the non-gaspath side. Support hardware supports the airfoil piece via the first platform radial flange. A thermal insulation element is situated adjacent the first platform radial flange. The support hardware supports the airfoil piece through the thermal insulation element.