Gas Turbine Fan Bushing Deformable Energy Absorption
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Solution Overview
Problem
The existing connection between the blades and the disc in turbomachines is prone to failure, leading to stress on fixings and potential breakage, which can result in the ejection of platforms into the airflow path and damage to downstream turbine engine components.
Innovation Solution
Incorporating a deformable sleeve with a rigid part and deformable part, where the deformable part comprises two parallel half-cylinders connected by webs, allows for tilting and energy absorption during blade impact, preventing platform ejection and facilitating maintenance by replacing only the deformed sleeve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid fixings are used to connect platform flanges to disc flanges, then connection strength is improved, but impact energy absorption is worsened leading to fastener breakage and platform ejection
Solution Approach 1:
The bushing structure is modified by introducing a deformable portion that changes the mechanical properties of the connection. The deformable portion allows the bushing to transition from a rigid structure to one with controlled flexibility, enabling it to absorb impact energy through elastic and plastic deformation while maintaining connection integrity.
Solution Approach 2:
The bushing incorporates a deformable portion that acts as a flexible element between the rigid platform flange and disc flange. This flexible portion deforms under impact loads, absorbing energy and preventing the transmission of destructive forces to the fasteners and platform structure.
2Reliability
If deformable zones are formed on platform side edges, then impact energy absorption is improved, but platform structural integrity is worsened leading to potential platform deformation
Solution Approach 1:
The deformability function is extracted from the platform structure itself and relocated to the bushing component. The bushing's deformable portion absorbs impact energy independently, preventing the transmission of deforming forces to the platform flanges and maintaining platform structural integrity.
Solution Approach 2:
The bushing acts as an intermediary element between the platform flange and disc flange. Its deformable portion serves as a buffer that absorbs impact energy, mediating the interaction between the rigid platform and disc structures and preventing direct force transmission that would cause platform deformation.
3Object-affected harmful factors
If abutment zones are formed on disc flanges, then platform contact with blades is prevented, but flexibility of connection is worsened reducing impact energy absorption capability
Solution Approach 1:
The protective function against blade contact is extracted from the disc flange abutment zones and relocated to the bushing's deformable portion. The bushing absorbs impact energy through deformation, eliminating the need for rigid abutment zones on the disc flange and preserving connection flexibility.
Solution Approach 2:
The bushing serves as an intermediary that absorbs impact energy through its deformable portion, replacing the need for abutment zones on the disc flange. This intermediary function maintains both protection against blade contact and flexibility of the platform-disc connection.
4Strength
If threaded rods are used to fix platform flanges to disc flanges, then connection strength is improved, but maintenance complexity is worsened requiring complete assembly disassembly for bushing replacement
Solution Approach 1:
The bushing is designed as a separable component that can be independently accessed and replaced. The deformable portion is structured to allow removal and installation without requiring disassembly of the threaded rod connections between the platform flange and disc flange, simplifying maintenance operations.
Solution Approach 2:
The bushing is designed as a removable component that can be extracted and replaced independently from the threaded rod assembly. This extraction capability allows maintenance personnel to replace deformed bushings without disassembling the fastening system, significantly reducing maintenance complexity.
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 effectively absorbs impact energy, preventing platform ejection and reducing damage to the turbomachine, while allowing for efficient maintenance by replacing only the deformed sleeve, thus maintaining the platform's position until engine stoppage.
Implementation Method 1
the deformable part being intended to allow tilting of the platform in the event of an impact of a blade on the platform and to absorb part of the energy of the impact
Data Source
Figure 1
Figure 2~4
AI summary
turbomachine blower (10), comprising blades (12) and inter-blade platforms (18) having radial flanges (20) fixed to flanges (22) of a rotor disc (16) by means of threaded rods inserted into bushings (26) mounted in orifices of the flanges of the platforms (18), wherein each bushing (26) includes at least one deformable portion (30) interposed transversely between the threaded rod (24) and an edge of the orifice in which the bushing (26) is mounted, this deformable portion (30) being intended to permit tilting of the platform (18) in the event of a collision of a blade (12) with the platform (18) and to absorb part of the energy of the collision.