Combustor Support Structure With Radial Studs for Thermal Expansion
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Solution Overview
Problem
Conventional combustor section support structures in gas turbine engines face issues with thermal mismatches causing high stresses due to different thermal expansion rates of components, leading to inefficiencies and increased weight and cost, and traditional systems fail to properly meter air into the combustor, creating hot spots.
Innovation Solution
A combustor section support structure that includes radial stud assemblies allowing radial movement of the fuel manifold relative to the engine case while fixing it axially, using ball joint assemblies to prevent axial movement and accommodate thermal expansion, thereby reducing stress and improving sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional rigid support structures are used to connect combustor components, then structural stability is maintained, but high thermal stresses occur due to thermal expansion mismatches between components at different temperatures
Solution Approach 1:
The support structure transitions from a rigid fixed connection to a dynamic mechanism that allows controlled movement. The stud assembly with slot and pivot joint enables the fuel manifold to move radially outward with thermal expansion while maintaining axial positioning, accommodating differential thermal expansion between the cold fuel manifold and hot combustor components without generating excessive thermal stresses
Solution Approach 2:
The support mechanism changes its constraint parameters based on thermal conditions. At operating temperatures, the fuel manifold expands radially and the support structure accommodates this by allowing radial movement through the slot-pivot mechanism while maintaining axial fixation, effectively adapting the structural parameters to thermal expansion requirements
2Stress or pressure
If burner seals and labyrinth seals are used to accommodate thermal expansion, then thermal stress is reduced, but air metering precision deteriorates causing hot spots in combustor
Solution Approach 1:
The invention removes the intermediary seal components (burner seals, labyrinth seals) from the connection between fuel injectors and engine case. By directly mounting fuel injectors to the engine case with precise positioning features, it eliminates the air leakage paths that these seals create, thereby maintaining precise air metering while still accommodating thermal expansion through the stud assembly mechanism
3Stress or pressure
If multiple seal components are used to accommodate thermal expansion, then thermal stress is managed, but device complexity and weight increase
Solution Approach 1:
The invention combines multiple functions into integrated components. The stud assembly with slot and pivot joint simultaneously provides thermal expansion accommodation, axial positioning, and radial movement capability in a single integrated mechanism, eliminating the need for separate burner seals, labyrinth seals, and adjustment mechanisms, thereby reducing overall device complexity and weight
4Force
If load is carried through hot components like dome plate and combustor liner, then structural support is provided, but component strength decreases due to high temperature
Solution Approach 1:
The invention introduces a cold fuel manifold as an intermediary structural element. The fuel manifold, which remains relatively cool due to fuel flow, serves as the primary load-bearing component that carries the weight of combustor components. This transfers the mechanical load away from hot components like the dome plate and combustor liner to a cooler, stronger structure, thereby maintaining higher component strength while still providing necessary structural support
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 stress and weight by allowing radial movement of the fuel manifold, maintaining a sealed relationship, and ensuring proper air metering, thus enhancing the performance and efficiency of the combustor section.
Implementation Method 1
Axial thermal expansion of different components (such as engine case and combustor liner) can occur because of different material properties and different temperatures. Also, radial thermal expansion can occur within circular components which are heated (such as engine case).
Implementation Method 2
These thermal mismatches can cause high stresses in components which are connected rigidly.
Data Source
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AI summary
A combustor section support structure (100) can include a fuel manifold (101) and one or more radial stud assemblies (103) connected to the fuel manifold (101) and configured to allow the fuel manifold (101) to move radially relative to an engine case (105) and to fix the fuel manifold (101) axially relative to the engine case (105). Each of the one or more radial stud assemblies (103) can include a first portion (103a) mounted to the fuel manifold (101) and a second portion (103b) configured to mount to an engine case (105). The first portion (103a) and the second portion (103b) can be configured to slide relative to each other to allow relative radial movement, but to prevent substantial axial relative movement. The first portion (103a) and the second portion (103b) form a ball joint assembly configured to allow misalignment induced rotation at the ball joint assembly.