CMC Heat Shield Collar System for Combustor Dome Attachment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing combustor assemblies in gas turbine engines face challenges with heat shields that require cooling due to high combustion gas temperatures, leading to increased turbine emissions and reduced performance, and complex fabrication and assembly of ceramic matrix composite (CMC) heat shields with intricate shapes.
Innovation Solution
A combustor assembly design featuring a CMC heat shield with a collar system that includes a split-ring collar and attachment pieces to securely attach the heat shield to the combustor dome, accommodating thermal expansion differences and providing anti-rotation features, while simplifying the fabrication process through a method involving layup of CMC plies and subsequent processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal heat shields are used in combustor assemblies, then they can protect the dome from combustion gas heat, but they require cooling fluid flow which increases turbine emissions and reduces performance
Solution Approach 1:
The patent applies ceramic matrix composite (CMC) materials for the heat shield, which can withstand high temperatures without requiring active cooling. The CMC material provides both thermal protection and structural integrity, eliminating the need for cooling fluid flow that would otherwise increase emissions and reduce turbine performance.
2Reliability
If CMC heat shields with complex shapes are fabricated, then they can provide effective thermal protection, but they require complex tooling and intricate assembly with numerous metal pieces
Solution Approach 1:
The collar is divided into a first piece and a second piece that can be separately assembled around the heat shield. This segmentation allows for easier fabrication and assembly, as the pieces can be attached to opposite sides of the heat shield and secured with fewer fasteners, reducing overall assembly complexity while maintaining effective thermal protection.
3Productivity
If CMC heat shields are used to withstand extreme temperatures, then turbine performance can be improved, but they have different thermal expansion characteristics that complicate attachment to the combustor dome
Solution Approach 1:
The attachment features are specifically designed to accommodate thermal expansion differences between the CMC heat shield and the combustor dome. The collar and attachment piece include features that allow for differential movement and expansion, ensuring reliable attachment while maintaining turbine performance benefits from the high-temperature CMC material.
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 the need for cooling fluids, enhances turbine performance and efficiency, minimizes emissions, and simplifies the fabrication and assembly of CMC heat shields by using a collar system that accounts for thermal expansion and maintains the heat shield's position relative to the dome.
Implementation Method 1
a combustor assembly with one or more features for fastening a CMC heat shield to a combustor dome that compensates for any difference in thermal expansion between the CMC heat shield and the combustor dome
Data Source
AI summary
Combustor assemblies having heat shields and features for attaching the heat shields are provided. For example, a combustor assembly includes a combustor dome defining an aperture, and a heat shield defining an opening and including a cup extending about the opening that extends toward the aperture of the combustor dome. The combustor assembly also includes a collar comprising a first piece and a second piece that each surround a portion of the heat shield cup. The collar may include a first arm, a second arm, and a body connecting the first and second arms such that the collar defines a recess between the first and second arms. The combustor assembly also may include an attachment piece with a flange that is positioned in the recess with a heat shield flange; the attachment piece attaches to the combustor dome to couple the heat shield and the combustor dome.