Hollow Turbomachine Blade Root Fabrication via Segmented Diffusion Bonding
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Solution Overview
Problem
The existing methods for manufacturing hollow blades for turbomachines are costly due to high material and machining expenses, primarily because they require machining of thick plates or multiple parts with complex profiles, which are limited by hot buckling criteria and result in inefficient use of material.
Innovation Solution
A method where only one primary part has a complex shape, with spare material used to form the root part, and a third part acts as a central support, allowing for diffusion bonding and superplastic forming to create the blade, reducing material and machining costs by using simpler elements like sheet metal and forging techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick plates are used to make external parts by machining, then the blade root can be formed with sufficient material volume, but the microstructure becomes coarse and manufacturing costs increase
Solution Approach 1:
The blade is divided into multiple external parts that are manufactured separately and then assembled through diffusion bonding. This segmentation allows each part to be made from thin plates with fine microstructure, while the assembled root achieves the required strength and material volume.
Solution Approach 2:
The blade root is formed as a composite structure assembled from multiple bonded plates. This composite approach enables the root to achieve sufficient material volume and strength while maintaining fine microstructure in each constituent plate, avoiding the coarse grain structure that results from machining thick plates.
2Ease of manufacture
If multiple external parts with complex profiles are machined separately, then the blade preform can be assembled, but material costs and machining costs become extremely high
Solution Approach 1:
The blade is segmented into multiple external parts that can be manufactured using cost-effective processes like rolling and simple machining, then assembled via diffusion bonding. This avoids the need to machine entire complex root structures from expensive thick plates, significantly reducing material and machining costs.
Solution Approach 2:
The manufacturing approach changes from machining thick plates to assembling thin plates through diffusion bonding. This parameter change in the manufacturing process enables the use of cheaper, more efficient production methods for each component while achieving the required root geometry through assembly.
3Manufacturing precision
If thin plates are bonded together to form assemblies, then the microstructure is improved, but the root geometry is limited by hot buckling criterion
Solution Approach 1:
The blade root is constructed from multiple segmented plates that are diffusion-bonded together. This segmentation allows the root to achieve the required thickness and geometry by stacking multiple thin plates, overcoming the hot buckling limitation that would prevent forming thick roots from single thin plates.
Solution Approach 2:
The root is formed as a composite structure of multiple bonded plates, enabling the achievement of sufficient root thickness and complex geometry while maintaining the fine microstructure of thin plates. The composite construction bypasses the hot buckling criterion that limits single-plate thickness.
4Ease of manufacture
If two external parts are made with complex profiles to form the root, then the blade preform can be created, but the device complexity and manufacturing cost increase
Solution Approach 1:
The complex root structure is achieved by segmenting the blade into multiple simpler external parts that are assembled together. This segmentation reduces the complexity of individual parts while maintaining the overall root geometry, making manufacturing more economical.
Solution Approach 2:
The external parts are designed to serve multiple functions: they form the aerodynamic surfaces and collectively build the root structure through diffusion bonding. This multi-functionality reduces the need for separate complex root-forming operations, simplifying the overall manufacturing process.
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 approach significantly lowers fabrication costs by optimizing material use and machining, enabling the production of hollow blades with improved microstructure and aerodynamic profiles at reduced expenses.
Implementation Method 1
diffusion bonding of the preform
Implementation Method 2
undergoes a superplastic forming in order to make a blade with approximately its final shape
Data Source
AI summary
Method of manufacturing a hollow blade (1) for a turbomachine in which the blade (1) is made from a preform (14) obtained from external primary parts (28, 30). In order to reduce costs, the root part (2) of the blade is formed from spare material (34) entirely located on only one of the two external primary parts of the preform (14).