Vane Arc Segment Insulation Fit for Thermal Stress Reduction
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Solution Overview
Problem
Implementing ceramic matrix composite (CMC) materials in gas turbine 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 hollow airfoil piece with a radial flange and thermal insulation element, where the thermal insulation element is machined to fit closely with the radial flange using a digital three-dimensional model, reducing play and thermal conductance, and is made of ceramic or ceramic matrix composite materials to minimize thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling methods are applied to CMC airfoils to improve durability, then temperature control is improved, but thermal gradients and thermal stress increase
Solution Approach 1:
A thermal insulation element made of CMC material is introduced as an intermediary component between the cooling system and the airfoil structure. This mediator allows controlled thermal isolation, enabling cooling to be applied where needed while preventing harmful thermal gradients and stress concentrations in critical areas of the airfoil.
2Strength
If thermal insulation element is added to reduce thermal stress, then thermal stress resistance is improved, but device complexity increases
Solution Approach 1:
The thermal insulation element is constructed from the same CMC material as the airfoil itself, creating a homogeneous material system. This eliminates material interface complexities and compatibility issues, reducing overall device complexity while maintaining thermal stress resistance benefits.
3Manufacturing precision
If light scan and machining are used to reduce play, then manufacturing precision is improved, but manufacturing complexity increases
Solution Approach 1:
A digital three-dimensional model is created through light scanning before the actual machining process. This preliminary digital representation allows for precise planning and simulation of the machining operations, enabling high manufacturing precision to be achieved while minimizing trial-and-error and rework, thus reducing overall manufacturing complexity.
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 durability and maintaining high-temperature resistance while minimizing thermal gradients, thus improving the performance and longevity of CMC airfoils in gas turbine engines.
Implementation Method 1
a thermal insulation element is located adjacent the radial flange
Implementation Method 2
performing a light scan of the radial flange to produce a digital three-dimensional model of the radial flange
Data Source
AI summary
Disclosed is a method of reducing play in a vane arc segment. The vane arc segment includes an airfoil piece that defines first and second platforms and a hollow airfoil section that has an internal cavity and that extends between the first and second platforms. The first platform defines a gaspath side, a non-gaspath side, and a radial flange that projects from the non-gaspath side. Support hardware supports the airfoil piece via the radial flange, and a thermal insulation element is located adjacent the radial flange. The method includes performing a light scan of the radial flange to produce a digital three-dimensional model of the radial flange, and then machining the thermal insulation element in accordance with the digital three-dimensional model to provide a low-tolerance fit between the radial flange and the thermal insulation element that limits play between the airfoil piece and the thermal insulation element.