Gas Turbine Cooling Cover with Elastomeric Flexure
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Solution Overview
Problem
The existing cooling passage covers in gas turbines suffer from leakage of cooling air due to sliding sealing members, leading to reduced efficiency and increased operational costs, as they require frequent replacement and are not designed to withstand thermal deformation and centrifugal forces effectively.
Innovation Solution
A cooling passage cover with a cylindrical cover portion and a flexible portion that allows axial flexure, integrated with the cover, which absorbs distortion and deformation, reducing air leakage and eliminating the need for replacement parts by using a radially bulging peripheral wall and drain holes to manage condensation droplets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a sealing member is provided to allow sliding movement in the axial direction to absorb thermal deformation, then the cover can accommodate distortion, but cooling air leakage occurs in the sliding portion
Solution Approach 1:
The patent employs a flexible portion made of elastomeric material that can elastically deform in the axial direction to absorb thermal distortion. This flexible membrane structure maintains sealing effectiveness while accommodating dimensional changes, eliminating the need for sliding sealing members that cause leakage.
Solution Approach 2:
The invention changes the physical state of the sealing mechanism from rigid sliding contact to elastic deformation. The elastomeric material transitions from a fixed sealing surface to a dynamically adaptable membrane that deforms with thermal expansion, maintaining seal integrity under varying thermal conditions.
2Adaptability or versatility
If a sliding sealing member is used to allow axial movement, then thermal deformation can be absorbed, but the sealing member wears and requires frequent replacement
Solution Approach 1:
The elastomeric flexible portion has no moving parts and experiences no mechanical wear like sliding sealing members. The material's elasticity allows it to repeatedly deform and recover without degradation, significantly extending service life and eliminating replacement needs.
Solution Approach 2:
The invention replaces the mechanical sliding sealing mechanism with an elastic deformation-based sealing system. Instead of relying on friction and contact between sliding surfaces, the system uses elastic recovery to maintain sealing, eliminating wear and extending operational life.
3Manufacturing precision
If the cooling passage cover is made rigid to maintain structural strength, then manufacturing precision is improved, but the cover cannot absorb distortion and deformation
Solution Approach 1:
The cooling passage cover is divided into a rigid cover portion that maintains structural strength and a separate flexible portion that absorbs distortion. This segmentation allows each component to optimize its function: the rigid portion provides manufacturing precision and structural integrity, while the flexible elastomeric portion accommodates thermal deformation.
Solution Approach 2:
Different portions of the cover have different mechanical properties. The cover portion is made rigid for structural strength and precision, while the flexible portion is made elastomeric for distortion absorption. This local differentiation of material properties allows simultaneous achievement of both structural integrity and thermal adaptability.
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 significantly reduces cooling air leakage and extends the lifespan of the cover, improving the efficiency of the gas turbine by maintaining airtightness and preventing the accumulation of condensation droplets, while allowing for long-term operation without the need for replacement parts.
Implementation Method 1
a flexible portion that is formed integrally with the cover portion and allows flexure in an axial direction of the turbine
Implementation Method 2
a temperature difference between an upstream side (a front side) and a downstream side (a rear side) of a flow of combustion gas in the turbine centering on the cavity 53 is large, and thus distortion occurs in the cavity 53 in an axial direction of the turbine
Implementation Method 3
because opposite ends of a rotor 4 are supported by bearings and a central part of the rotor 4 deforms in a radial direction of the turbine due to a centrifugal force
Implementation Method 4
the flexible portion is formed by a peripheral wall of the cover portion bulging radially outward and formed thinner than the cover portion
Data Source
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AI summary
To provide a cover (54) of a cooling passage that forms a cooling passage (5) for supplying cooling air to a turbine rotor blade at the last stage via inside of a disk (35) of a turbine, and the cover comprises: a cylindrical cover portion (541) that covers a cavity (53) provided in a annular pattern in an outer circumference of the disk (35) in a mode where a first passage (51) opened from inside of the disk (35) to the cavity (53) and a second passage (52) opened from a cooling passage of the turbine rotor blade at the last stage to the cavity (53) are connected to each other; and a flexible portion (542) that is formed integrally with the cover portion (541) and allows flexure in an axial direction of the turbine.