Textured Stator Vane Mounting Feet for Braze Overflow Control
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Solution Overview
Problem
Existing gas turbine engine stator stages face challenges in maintaining secure braze joints between vanes and shrouds, particularly due to braze material overflow and migration to high-stress fillet transitions, leading to potential cracking and delamination.
Innovation Solution
Implementing texturing on the periphery of vane mounting feet, such as knurling, grooves, or abrasions, to trap and accommodate braze material, preventing overflow to fillet transitions and improving aerodynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If smooth periphery of mounting foot is used, then braze material can flow freely, but braze material overflows to fillet transitions causing cracking and delamination
Solution Approach 1:
The mounting foot periphery is given a localized textured surface with specific surface roughness characteristics. This local modification creates regions that selectively interact with braze material - the textured areas promote braze material retention while smooth areas allow controlled flow, preventing overflow to fillet transitions without compromising overall joint integrity
Solution Approach 2:
The textured surface is applied to the mounting foot periphery before the brazing process. This preliminary surface preparation creates predetermined zones that will trap and accommodate braze material during the subsequent brazing operation, proactively preventing the harmful overflow effect before it occurs
2Reliability
If texturing is applied to mounting foot periphery, then braze material overflow is prevented, but manufacturing complexity increases
Solution Approach 1:
The surface characteristics of the mounting foot periphery are modified by changing physical parameters such as surface roughness, texture depth, and pattern geometry. These parameter changes create the desired braze material retention effect without fundamentally altering the mounting foot structure or requiring complex additional components
3Manufacturing precision
If braze material is allowed to flow to fillet transition, then complete joint coverage is achieved, but aerodynamic performance deteriorates
Solution Approach 1:
The textured surface is applied locally to specific regions of the mounting foot periphery where braze material retention is most critical. This localized treatment ensures adequate joint coverage in key areas while preventing braze material from reaching the aerodynamically sensitive fillet transition regions, thus maintaining aerodynamic performance
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
Enhances the integrity of braze joints by reducing cracking and delamination risks while maintaining aerodynamic efficiency by limiting braze material overflow, thus improving the overall performance and reliability of the stator stage.
Implementation Method 1
The mounting foot has a periphery with texturing. Braze material joins the texturing to a surface of the associated aperture.
Data Source
Figure 1
Figure 2
Figure 3~3A
AI summary
A stator stage (20) has: at least a first shroud (22; 24) being an inner diameter shroud (22) or an outer diameter shroud (24); and vanes (26) mounted to the first shroud (22; 24). Each vane (26) has a mounting foot (32; 34) received in an aperture (48) in the first shroud (22; 24) and brazed thereto. The mounting foot (32; 34) has a periphery (46) with texturing. Braze material joins the texturing to a surface (50) of the associated aperture (48).