Turbine Seal Segment Mounting Insert for Thermal Expansion
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Solution Overview
Problem
In gas turbine engines, traditional arrangements of components with different coefficients of thermal expansion often fail to accommodate the varying expansion and contraction, leading to potential misalignment and inefficiencies due to the differing thermal expansion rates of materials used in shrouds and vanes exposed to high temperatures.
Innovation Solution
A turbine assembly featuring a ceramic matrix composite seal segment supported by a metallic carrier, with a mounting insert that applies a predetermined force load to maintain engagement and limit axial movement, utilizing a protrusion and bias member to ensure a consistent force threshold within a predetermined range, thereby addressing thermal expansion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional arrangements of components with different coefficients of thermal expansion are used, then the structure is simple and easy to manufacture, but the components cannot accommodate varying expansion and contraction, leading to misalignment and inefficiencies
Solution Approach 1:
The mounting insert incorporates a spring element that provides dynamic, flexible connection between the ceramic seal segment and metallic carrier. This spring mechanism allows the assembly to dynamically adapt to thermal expansion and contraction of the ceramic component while maintaining proper engagement and sealing, resolving the contradiction between adaptability and structural simplicity.
2Reliability
If components with different thermal expansion rates are rigidly coupled, then the structure is stable and simple, but thermal expansion differences cause misalignment and potential damage
Solution Approach 1:
The spring element in the mounting insert acts as a cushioning mechanism that anticipates and absorbs thermal expansion stresses before they can cause damage. By providing this compliant element in advance, the design protects the rigidly coupled ceramic and metallic components from thermal stress-induced misalignment and damage while maintaining engagement stability.
3Ease of manufacture
If a rigid mounting arrangement is used, then manufacturing is simple, but thermal expansion causes excessive stress and potential component failure
Solution Approach 1:
The mounting insert changes the mechanical parameter of connection rigidity by introducing a spring element. This allows the assembly to maintain simple manufacturing processes while fundamentally altering the stress characteristics to accommodate thermal expansion, thereby preventing excessive stress and component failure without complicating the manufacturing process.
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 maintains the seal segment's engagement with the carrier, ensuring efficient operation by controlling thermal expansion and preventing damage from excessive stress, thereby enhancing the turbine assembly's reliability and performance.
Implementation Method 1
The bias member may be engaged with the insert body and the seal segment to apply a force load to the seal segment
Implementation Method 2
Some shrouds and vanes positioned in the turbine may be exposed to high temperatures from products of the combustion reaction in the combustor. Such shrouds and vanes sometimes include components made from materials that have different coefficients of thermal expansion. Due to the differing coefficients of thermal expansion, the components of some turbine assemblies expand at different rates when exposed to combustion products
Data Source
AI summary
A turbine assembly adapted for use in a gas turbine engine includes a seal segment and a carrier. The seal segment includes a shroud wall that extends circumferentially partway around an axis and a mount post that extends radially outward away from the shroud wall. The carrier is shaped to define a channel that receives at least a portion of the mount post. A mounting insert is used to urge the carrier and mount post toward one another.