Turbomachine Bladed Disk Splined Shaft Assembly
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Solution Overview
Problem
Conventional turbomachine shaft assemblies with one-piece bladed disks and low-pressure compressor rotors are cumbersome, difficult to disassemble, and do not allow for a low hub ratio, which is desirable for engines with small diameters and multiple compressor stages, compromising mechanical strength and ease of maintenance.
Innovation Solution
A one-piece bladed disk with a frustoconical profile and a truncated cone attachment web, featuring a cylindrical splined collar and heel, is adapted to be shrunk onto a low-pressure compressor shaft, utilizing splines and a clamping mechanism for secure attachment and easy disassembly, allowing coaxial alignment and axial support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional flange systems are used to attach the bladed disk and low-pressure compressor rotor to the shaft, then the assembly is structurally stable, but the disassembly process becomes complex and time-consuming
Solution Approach 1:
The attachment system is segmented into modular components: splined collars on the bladed disk and compressor rotor, complementary splines on the shaft, and independent clamping members. This segmentation allows each component to be attached or detached independently, simplifying the disassembly process while maintaining structural stability during operation.
2Strength
If the hub ratio is reduced to achieve low hub ratio fans, then the aerodynamic performance improves, but the mechanical strength of the flange and installation radius are compromised
Solution Approach 1:
The attachment mechanism transitions from a two-dimensional flange interface to a three-dimensional splined collar system with axial, radial, and rotational dimensions. The splined collars extend axially along the shaft with multiple spline teeth providing radial engagement, creating a distributed stress field that maintains mechanical strength even when the hub ratio is reduced.
3Power
If multiple stages of movable blades are added to the low-pressure compressor, then the compression ratio increases, but the device complexity and assembly difficulty increase
Solution Approach 1:
The splined attachment system serves multiple functions simultaneously: it provides rotational coupling, axial positioning, and mechanical strength transmission for the entire multi-stage compressor rotor assembly. This universal attachment mechanism handles all structural requirements for complex multi-stage compressors without requiring additional specialized components for each stage.
4Strength
If the bladed disk is made as a one-piece structure with pinned blades, then the structural integrity improves, but the disassembly and maintenance accessibility deteriorates
Solution Approach 1:
The clamping members are extracted as separate, independently accessible components that can be removed without disassembling the one-piece bladed disk structure. The splined collars are also designed to be extractable from the shaft, allowing maintenance personnel to access and service the bladed disk or compressor rotor by simply removing these external attachment components rather than disassembling the entire assembly.
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 enables a low hub ratio while ensuring mechanical strength and facilitating easy disassembly under wing conditions without requiring disassembly of the low-pressure compressor, maintaining coaxial alignment and reducing the hub and installation radii, thus enhancing mechanical strength and aerodynamic performance.
Implementation Method 1
said disk portion being adapted to be shrunk onto a low-pressure compressor shaft
Data Source
AI summary
An assembly includes a one-piece bladed disk, at least one low-pressure compressor rotor, and a low-pressure compressor shaft. The bladed disk and the low-pressure compressor rotor are both adapted to be shrunk onto the low-pressure compressor shaft and mechanically attached to it by sets of splines. At least one clamping member blocks axially the different collars with respect to the shaft.