Removable Stator Vane for Gas Turbine Compressor Mid-Plane Balancing
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Solution Overview
Problem
Conventional methods for trim balancing a compressor mid-plane rotor assembly in gas turbines require partial disassembly of the compressor case, leading to high time, energy, and risk due to the need to access the balance location underneath the blade platform, and lack effective sealing at the compressor mid-plane.
Innovation Solution
A stator assembly with an inner diameter ring assembly, an outer diameter ring assembly, and a removable stator vane that allows access to the mid-plane trim balance rotor disc via a radial pathway, providing sealing and interference fits to prevent fluid passage and foreign object intrusion, enabling in situ trim balancing without disassembling the compressor case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional trim balancing methods are used requiring partial disassembly of compressor case, then access to balance location is achieved, but time, energy, and risk increase significantly
Solution Approach 1:
The stator assembly is segmented into removable stator vanes that can be individually extracted through the compressor case, allowing access to the balance location without disassembling the entire compressor case. This segmentation enables selective access while maintaining the integrity of the overall structure.
Solution Approach 2:
A removable stator vane is extracted through the compressor case to create an access pathway to the mid-plane balance location. This extraction principle allows direct access to the rotor balance area without requiring partial disassembly of the compressor case, significantly reducing maintenance time and risk.
2Ease of operation
If conventional trim balancing methods are used requiring partial disassembly, then access to balance location is achieved, but complexity and risk of disassembly increase
Solution Approach 1:
The stator assembly is designed with segmented, removable vanes that can be individually accessed and removed through the compressor case. This segmentation simplifies the access procedure by allowing technicians to work with individual components rather than disassembling the entire compressor case structure.
Solution Approach 2:
The removable stator vane is extracted through the compressor case to provide direct access to the balance location. This extraction approach reduces procedural complexity by eliminating the need for complex disassembly and reassembly operations, requiring only the removal and reinstallation of a single stator vane.
3Ease of operation
If seal ring with aperture is used for access, then access to rotor disc is enabled, but fluid passage through aperture occurs
Solution Approach 1:
The removable stator vane is extracted through the compressor case to create an access pathway that does not require a permanent aperture in the seal ring. This extraction approach allows temporary access during maintenance while maintaining the sealing integrity of the seal ring during normal operation.
Solution Approach 2:
The seal ring aperture is dynamically controlled by the removable stator vane, which can be inserted to seal the aperture during operation and removed to provide access during maintenance. This dynamic configuration allows the system to switch between sealed and accessible states, eliminating fluid leakage during operation while enabling access when needed.
4Object-generated harmful factors
If removable stator vane with interference fit is used, then sealing against fluid passage is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The removable stator vane is designed to be extracted through the compressor case, creating a temporary access pathway. The interference fit between the vane and its seating provides sealing during operation, but the design accommodates reasonable manufacturing tolerances by relying on the compressive force of the interference fit rather than requiring extremely precise clearance fits.
Solution Approach 2:
The interference fit parameters (dimensions, tolerances, material properties) are optimized to provide sufficient sealing force while accommodating practical manufacturing capabilities. The design balances the sealing requirement with manufacturability by selecting appropriate interference fit values that ensure fluid tightness without requiring ultra-precise manufacturing.
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
Enables efficient trim balancing and sealing of the compressor mid-plane rotor assembly in situ, reducing vibration, increasing reliability, and extending the service life of engine components by allowing access and adjustment of the mid-plane trim balance rotor disc without disassembling the compressor case, while maintaining gas path flow sealing and protecting against foreign object damage.
Implementation Method 1
the profile of the button being sized and shaped to match the profile of the shroud ring aperture so as to form an interference fit, such that, when the removable stator vane is seated within the stator assembly, the button completely fills the shroud ring aperture and covers the seal ring aperture restricting fluid passage from one side of the seal ring to the other side of the seal ring along the radial axis R
Implementation Method 2
the profile of the outer diameter ring assembly aperture corresponding to a profile of the platform to form an interference fit with the platform
Implementation Method 3
labyrinth seals located on the mid-plane trim balance rotor disc underneath the seal ring preventing fluid passage from one side of the seal ring to the other side of the seal ring along longitudinal axis L of stator assembly
Data Source
Figure 1
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AI summary
A stator assembly (100), at a compressor mid-plane in a gas turbine engine, to be mounted around a rotor disc (810), enables access to the rotor disc (810) (e.g., for trim balancing), without requiring disassembly of the stator assembly (100) and/or a compressor case (700), via a removable stator vane (400). The stator assembly (100) may comprise vane apertures (222, 312, 322), aligned along a radial axis, that hold the removable stator vane (400) when inserted into the stator assembly (100), and provide a radial pathway to the rotor disc (810), when the removable stator vane (400) is removed. A case access assembly (600) may seal the removable stator vane (400) in place within a compressor case (700) when engaged, and provide access to the removable stator vane (400) and radial pathway through the compressor case (700) when disengaged. This enables trim balancing of a mid-plane compressor rotor assembly (800).