Combustor-Vane Brush Seal Assembly With Cooling Bypass Channels
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Solution Overview
Problem
Gas turbine engines face uncontrolled leakage due to inadequate sealing between the combustor and turbine sections, leading to hot spots and bow wave distress, as existing sealing arrangements may not maintain consistent contact throughout operation and can disrupt cooling mechanisms.
Innovation Solution
The implementation of a dual-seal assembly system, comprising a brush seal and a conformal seal, with a brush seal backing plate, retaining ring, and bristles, along with cooling channels to direct air for controlled cooling, ensuring effective sealing and minimizing leakage while accommodating thermal expansion and movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single seal arrangement is used between the combustor and turbine section, then the device complexity is reduced, but sealing efficiency deteriorates leading to uncontrolled leakage
Solution Approach 1:
The sealing system is divided into two distinct seal arrangements: a primary seal (labyrinth seal) and a secondary seal (brush seal). Each seal performs a specific function - the primary seal provides the first line of defense against leakage while the secondary seal ensures complete sealing. This segmentation allows each seal to be optimized for its specific role, improving overall sealing efficiency without requiring one overly complex seal design
Solution Approach 2:
The brush seal acts as an intermediary element between the combustor shell and turbine vane assembly, providing a secondary sealing mechanism that complements the primary labyrinth seal. The brush seal's flexible bristles accommodate relative movement and thermal expansion between components while maintaining sealing contact, effectively bridging the gap between rigid structural elements
2Reliability
If sealing arrangements are made to maintain contact throughout operation, then sealing efficiency is improved, but thermal expansion and movement are restricted causing distortion
Solution Approach 1:
The brush seal incorporates flexible bristles that can dynamically adjust their position and contact pressure in response to thermal expansion and relative movement between the combustor shell and turbine vane assembly. This dynamic flexibility allows the seal to maintain consistent sealing contact throughout engine operation without restraining the natural thermal expansion of components, preventing distortion while ensuring sealing consistency
Solution Approach 2:
The seal assembly design allows contact pressure and bristle deflection parameters to change in response to operating conditions. As temperature increases and components expand, the brush seal's contact pressure naturally adjusts to maintain sealing effectiveness. This parameter adaptation enables the seal to function consistently across the full operating range without causing thermal stress or distortion to the connected components
3Loss of energy
If leakage is reduced through improved sealing, then energy efficiency is improved, but cooling mechanisms are disrupted causing hot spots
Solution Approach 1:
The cooling channels are strategically positioned to provide localized cooling air flow to specific high-temperature zones, such as the leading edges of turbine vanes and the combustor shell interface. This localized cooling approach allows the seal to reduce overall gas leakage and improve energy efficiency while maintaining targeted cooling where thermal loads are highest, preventing hot spot formation without requiring complete sealing that would disrupt overall cooling flows
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 configuration enhances sealing efficiency, reduces uncontrolled leakage, prevents hot spots, and maintains controlled cooling, thereby improving the operational reliability and efficiency of gas turbine engines.
Implementation Method 1
at least one cooling channel extending from an exterior side of the first shell to an interior side of the first shell
Implementation Method 2
a brush seal forming a first seal between the first shell and a forward face of the first vane stage
Data Source
AI summary
A brush seal system includes a component including a first mating surface. The brush seal system further includes a brush seal including a brush seal backing plate, a retaining ring, and a plurality of bristles retained between the brush seal backing plate and the retaining ring. The brush seal backing plate includes a second mating surface mounted to the first mating surface. The brush seal system further includes at least one cooling channel extending from an exterior side of the component to an interior side of the component so as to bypass the brush seal.