Spring-Loaded CMC Combustor Liner Sealing
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Solution Overview
Problem
Ceramic matrix composite (CMC) combustor liners in gas turbine engines face challenges due to thermal expansion mismatches with metallic components, leading to stress concentrations, vibration-induced wear, and leakage, which hinder efficient operation at high temperatures.
Innovation Solution
A spring-loaded clamping assembly is used to apply axial force on CMC combustor liners, resisting vibration and ensuring a sealed contact despite thermal expansion differences, thereby maintaining a proper seal and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic matrix composite combustor liners are used to operate at high temperatures, then temperature resistance is improved, but stress concentrations and component failure occur due to thermal expansion mismatch with metallic components
Solution Approach 1:
The patent applies a spring-loaded mounting assembly that changes the mechanical constraints on the CMC liner. The spring mechanism allows the liner to expand freely in the axial direction while maintaining radial positioning, accommodating thermal expansion differences between CMC and metallic components without generating excessive stress concentrations.
Solution Approach 2:
The mounting assembly transitions from a rigid fixed constraint to a dynamic spring-loaded constraint. This allows the system to adapt to thermal expansion variations during operation, maintaining proper positioning while accommodating dimensional changes in the CMC liner as temperature increases.
2Stability of the object's composition
If ceramic matrix composite combustor liners are restrained and cooled on one surface, then structural stability is maintained, but stress concentrations develop leading to component failure
Solution Approach 1:
The spring-loaded assembly modifies the boundary conditions from fixed restraint to compliant support. This allows the liner to maintain structural stability while accommodating thermal gradients and cooling effects without developing damaging stress concentrations at constrained surfaces.
3Reliability
If spring-loaded clamping assembly is used to apply axial force on CMC combustor liners, then sealing and vibration resistance are improved, but device complexity increases
Solution Approach 1:
The spring acts as an intermediary element between the mounting structure and the CMC liner. It provides the necessary axial clamping force to ensure sealing contact while accommodating thermal expansion, and simultaneously dampens vibration between the liner and mounting structure, without requiring complex active control systems.
4Object-affected harmful factors
If spring-loaded clamping assembly is used to apply axial force on CMC combustor liners, then vibration resistance is improved, but device complexity increases
Solution Approach 1:
The spring mechanism serves as a vibration-damping intermediary between the rigid mounting structure and the CMC liner. It absorbs and dissipates vibrational energy through elastic deformation, reducing wear and preventing loose contact without requiring complex vibration control systems.
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 a sealed contact and resists vibration, preventing premature wear and leakage, leading to improved durability and efficiency of the combustor operation, reducing emissions and lowering overhaul costs.
Implementation Method 1
a first spring forcing the outer liner in an axial direction against the outer liner retainer
Data Source
AI summary
A combustor liner assembly of a gas turbine engine comprises a dome having a central axis aligned with an engine axis, the dome arranged at an inlet end of a combustor, a first spring disposed at a radially outward position of the dome, an outer liner retainer engaging a radially outer cowl and, the outer liner retainer having a sealing surface disposed in a radial plane for receiving an axial force, a ceramic matrix composite outer combustor liner having an outer liner sealing surface which is seated against the outer liner retainer, the first spring forcing the outer liner in an axial direction against the liner outer liner retainer, a ceramic matrix composite inner combustor liner having an inner liner sealing surface and engaging a radially inward surface of the dome, a second spring engaging the radially extending surface of the inner combustor liner, acting in an axial direction.