Unitary Gas Turbine Flow Path Assembly Positioning
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Solution Overview
Problem
Gas turbine engines face challenges with complex and heavy flow path assemblies due to separate components requiring numerous seals, which can lead to leakage and increased weight, and thermal expansion issues between ceramic matrix composite (CMC) and metallic materials.
Innovation Solution
A flow path assembly with a unitary construction, featuring a hub and spoke configuration using positioning members to center and constrain the assembly, allowing for thermal growth while integrating combustor and turbine portions as a single unitary structure, and allowing axial and radial movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate components are used to form the outer boundary and inner boundary of the flow path, then the flow path can be constructed with modular parts, but the number of parts increases and leakage points are created between components
Solution Approach 1:
The patent integrates the outer boundary and inner boundary components into a unified flow path assembly, eliminating the interfaces between separate components. This merging reduces the total number of parts and eliminates leakage points while maintaining the modular benefits of separate manufacturing and assembly capabilities.
2Reliability
If separate components with seals are used to minimize leakage, then leakage between components is reduced, but the weight and complexity of the gas turbine engine increase
Solution Approach 1:
By integrating the boundary components into a unified structure, the patent eliminates the need for multiple seals and sealing mechanisms. This reduces the overall weight of the engine while maintaining or improving leakage prevention through the continuous, seal-free interface between components.
3Temperature
If CMC flow path assembly is used, then high temperature performance is improved, but thermal expansion differences with metallic support components affect positioning
Solution Approach 1:
The patent employs positioning members with adjustable parameters that can accommodate thermal expansion. These positioning members are configured to allow for dimensional changes in the CMC flow path assembly as temperature varies, maintaining proper positioning despite the different thermal expansion rates between CMC and metallic materials.
Solution Approach 2:
The positioning members act as intermediaries between the CMC flow path assembly and the metallic support components. These intermediaries are designed to compensate for thermal expansion differences, allowing the CMC component to expand freely while maintaining its positional relationship with the metallic structure.
4Device complexity
If a unitary construction is used for the flow path assembly, then leakage is reduced and weight is decreased, but accommodation of thermal growth between different materials becomes more difficult
Solution Approach 1:
The patent incorporates dynamic positioning members that can adjust their configuration in response to thermal growth. These positioning members are designed with degrees of freedom that allow them to adapt to the dimensional changes of the CMC flow path assembly, maintaining proper positioning throughout the thermal cycle while preserving the benefits of unitary construction.
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
This solution reduces leakage, weight, and complexity by integrating components, while accommodating thermal expansion differences between CMC and metallic materials, maintaining proper positioning and performance of the flow path assembly.
Implementation Method 1
the CMC flow path assembly and the support components may thermally expand at different rates, which could affect the positioning of the flow path assembly within the gas turbine engine
Data Source
AI summary
Flow path assemblies having features for positioning the assemblies within a gas turbine engine are provided. For example, a flow path assembly comprises an inner wall and a unitary outer wall that includes an integral combustion portion and turbine portion, the combustor portion extending through a combustion section of the gas turbine engine and the turbine portion extending through at least a first turbine stage of a turbine section of the gas turbine engine. The flow path assembly further comprises at least two positioning members for radially centering the flow path assembly within the gas turbine engine. The positioning members extend to the flow path assembly from one or more structures external to the flow path assembly, constrain the flow path assembly tangentially, and allow radial and axial movement of the flow path assembly. Other embodiments for positioning flow path assemblies also are provided.