Gas Turbine Combustor Bristle Pack Heat Shield
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Solution Overview
Problem
Current heat shields in gas turbine combustors are prone to cracking and thermal barrier coating spallation due to thermal cycling, which compromises their effectiveness in protecting components from combustion gases.
Innovation Solution
A bristle pack with a base plate and extending bristles, potentially coated with a thermal barrier coating, is used to form a heat shield, deflector, or flare within the combustor, allowing for relative movement during thermal loading and enhanced protection without cracking or spallation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid piece of metal with thermal barrier coating is used as heat shield, then protection from combustion gases is achieved, but cracking and coating spallation occur due to thermal cycling
Solution Approach 1:
The heat shield is segmented into multiple bristles that can move independently relative to each other and the base plate. This segmentation allows the structure to accommodate thermal expansion and cyclic loading without developing cracks, as each bristle can deflect independently to absorb thermal stresses.
Solution Approach 2:
The heat shield transitions from a static solid structure to a dynamic bristle-based structure where bristles can move relative to the base plate and each other. This dynamic capability allows the heat shield to adapt to thermal cycling by permitting controlled movement that prevents crack formation and coating spallation.
2Strength
If a rigid heat shield structure is used, then structural strength is maintained, but thermal cycling causes cracking and thermal barrier coating failure
Solution Approach 1:
The rigid structure is divided into multiple bristle elements that maintain individual structural integrity while collectively providing heat shield functionality. Each bristle can move independently, preventing stress concentration that would lead to cracking and coating failure in rigid structures.
Solution Approach 2:
The heat shield's mechanical parameters change from fixed and rigid to flexible and movable. The bristles can deflect and move relative to the base plate, changing the structural response to thermal loading from brittle (rigid) to ductile (flexible), thereby preventing crack propagation and coating spallation.
3Object-affected harmful factors
If a solid heat shield is used, then component protection is achieved, but thermal expansion and contraction cause cracking
Solution Approach 1:
The heat shield incorporates dynamic movement capability through bristles that can deflect and move relative to the base plate during thermal cycling. This dynamic response allows the structure to accommodate thermal expansion and contraction without developing cracks, maintaining both protection functionality and structural stability.
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 bristle pack effectively shields combustor components from combustion gases, preventing cracking and thermal barrier coating failure, thus improving durability and performance under thermal cycling.
Implementation Method 1
A bristle pack with a base plate and extending bristles, potentially coated with a thermal barrier coating, is used to form a heat shield, deflector, or flare within the combustor, allowing for relative movement during thermal loading
Implementation Method 2
A bristle pack with a base plate and extending bristles, potentially coated with a thermal barrier coating, is used to form a heat shield, deflector, or flare within the combustor
Data Source
AI summary
A combustor for a gas turbine engine includes an inner liner and an outer liner positioned outward of the inner liner along the radial direction such that a combustion chamber is defined between the inner and outer liners. Furthermore, the combustor includes a fuel nozzle configured to supply fuel to the combustion chamber. Moreover, the combustor includes a bristle pack having a base plate and a plurality of bristles extending outward from the base plate such that the bristle pack forms at least a portion of at least one of a heat shield coupled to the fuel nozzle, a deflector of the combustor, or a flare of the combustor.