Turbine Nozzle Assembly Mechanical Weld Hybrid Interface
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Solution Overview
Problem
Turbine nozzle assembly fabrication using welds on both entrance and exit sides leads to distortion, increased costs, and lifting issues due to weld shrinkage, as well as the need for significant material removal to create sidewalls leading up to the airfoil.
Innovation Solution
A turbine nozzle assembly design incorporating mechanical interconnections with protruding hooks and corresponding recesses, along with axial and radial mechanical stops, allowing for welding on one side while maintaining assembly integrity, reducing distortion and cost by eliminating the need for flipping parts and minimizing material removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is performed on both entrance and exit sides of the nozzle assembly, then assembly integrity is achieved, but distortion and lifting occur due to weld shrinkage
Solution Approach 1:
The interface between the nozzle and ring is segmented into two distinct sides: a first side with a mechanical interconnection (protruding hook and recess) and a second side with a welded connection. This segmentation allows each side to fulfill different functions - the mechanical interconnection prevents lifting and distortion during welding, while the welded side provides strong permanent bonding.
Solution Approach 2:
The mechanical interconnection (protruding hook and recess) is established at the first side of the interface before welding occurs at the second side. This preliminary mechanical bonding prevents the nozzle from lifting off the ring due to weld shrinkage forces, thereby preventing distortion before it can occur during the welding process.
2Strength
If welding is performed on both sides of the nozzle assembly, then connection strength is improved, but cost increases due to flipping parts
Solution Approach 1:
The connection is segmented into a mechanical interconnection at the first side and a welded connection at the second side. This allows the assembly to achieve strong permanent bonding through welding on one side only, eliminating the need to flip the part for welding the opposite side, thereby reducing manufacturing cost and complexity.
3Strength
If welding is performed on the nozzle assembly, then permanent bonding is achieved, but material must be significantly removed to create sidewalls
Solution Approach 1:
The interface design segments the connection functions between mechanical interconnection and welded bonding, allowing the sidewalls to be formed with minimal material removal while still achieving strong permanent bonding through welding at the second side of the interface.
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 design reduces distortion, lowers costs, and enhances assembly stability by using mechanical interlocks to prevent weld shrinkage-induced lifting, while allowing for easier application of protective coatings and reducing stress concentrations, resulting in a more deterministic structure for analysis and operation.
Implementation Method 1
a second side of the interface is permanently coupled together via a weld
Implementation Method 2
weld shrinkage on the welded side
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Embodiments of this invention include a nozzle assembly (10, 100) for a turbine, the nozzle assembly (10, 100) including an airfoil (12, 102), inner and outer sidewall's (16, 106) and inner and outer ring's (20, 110). Each of these sidewalls and rings are coupled together at an interface (80) through a combination of a mechanical interconnection on one end and a welded connection on the other end. The mechanical interconnection includes either the sidewalls or the rings having a protruding hook (130) and the other having a corresponding hook recess (132). The interconnection can also include axial and radial mechanical stops. The configuration may further include one or more surfaces at an interface (80) between a ring and a sidewall angled away from the interface (80) to form a narrow groove (120). The configuration further may include a ring with a consumable root portion (122).