Wedge-Shaped Ceramic Heat Shield for Gas Turbine Combustion
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Solution Overview
Problem
Existing heat shields in gas turbine combustion chambers are inefficient in protecting the supporting structure from thermal overload due to geometric limitations and tolerance issues, allowing hot gas to penetrate through expansion gaps and cause damage.
Innovation Solution
A heat shield element with a spoiler shape that increases in height towards the peripheral sides, creating a projection to deflect hot gas flow and prevent ingress into expansion gaps, and a method to minimize expansion gaps by adjusting the width of heat shield elements to match ideal dimensions, ensuring effective protection despite component tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If small individual heat shield elements are used to allow thermal expansion, then thermal stress is prevented, but expansion gaps remain that allow hot gas penetration and thermal overload of the supporting structure
Solution Approach 1:
The heat shield element transitions from a conventional flat geometry to a three-dimensional spoiler shape with increased height in the direction of hot gas flow. This dimensional change creates a projection that extends beyond the supporting structure, forming an effective barrier against hot gas penetration into expansion gaps while preserving the individual element configuration for thermal expansion accommodation
2Reliability
If the supporting structure is protected from hot gas attack, then component life is extended, but geometric limitations of conventional heat shield elements leave uncovered surfaces and projecting edges vulnerable to thermal overload
Solution Approach 1:
The heat shield element employs asymmetric geometry with different heights on opposite peripheral sides, creating a spoiler shape that strategically extends over uncovered surfaces and projecting edges of the supporting structure. This asymmetric configuration provides enhanced protection for previously vulnerable areas while maintaining the necessary expansion gaps
3Object-affected harmful factors
If expansion gaps are minimized to reduce hot gas penetration, then thermal protection is improved, but tolerance zones of combustion chamber components result in excessively large gaps that cannot be optimally controlled
Solution Approach 1:
The invention converts the harmful effect of tolerance-induced gap variations into a beneficial outcome by designing the spoiler-shaped heat shield element to effectively block hot gas penetration even when gaps vary within tolerance zones. The projection geometry ensures protection regardless of the exact gap size, transforming the manufacturing challenge into a robust design feature
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 heat shield effectively prevents damage from hot gas ingress by redirecting gas flow and minimizing expansion gaps, thereby reducing thermal overload on the supporting structure and protecting adjacent components.
Implementation Method 1
the heat shield element changes the flow of a hot gas flowing in the direction over the hot side of the heat shield element so as to counter hot gas ingress into the expansion gap
Implementation Method 2
Ceramic materials are suitable for the material of the heat shield elements. In contrast to metallic materials, ceramic materials have high temperature resistance, corrosion resistance and low thermal conductivity
Data Source
AI summary
A heat shield element for a heat shield has a support structure. The heat shield element includes a hot side which can be exposed to hot gas, a cold side opposite the hot side, and peripheral sides connecting the hot side to the cold side. The heat shield element can be fastened to the support structure of the heat shield with the cold side facing the support structure and has a height running vertically to the cold side. The height of the heat shield element increases in a rising direction, the rising portion of the heat shield element running in the rising direction substantially up to at least one peripheral side or up to a projection that extends the hot side over the base surface of the cold side.