Segmented Shaft Torque Transmission for Turbine Nozzles
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Solution Overview
Problem
Existing turbine engine variable nozzle systems face durability, leakage, constructability, and installation issues due to challenges in translating torque from driver arms to nozzle airfoils, limiting their efficiency and reliability across varying operational conditions.
Innovation Solution
A segmented shaft torque transmission method is introduced, utilizing spherical bearings and universal joints to connect and secure segments of the shaft, allowing for efficient rotation of variable nozzle airfoils while preventing radial and rotational binding under load, and incorporating seals to mitigate leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional integrated shaft design is used to transmit torque from driver arm to nozzle airfoils, then the structure is simple, but durability and reliability deteriorate due to binding under load
Solution Approach 1:
The shaft is divided into multiple segments (first segment, second segment, third segment) that can rotate relative to each other about the radial axis. This segmentation allows each segment to independently accommodate radial binding forces while maintaining torque transmission, thereby improving durability and reliability without requiring a completely complex overall structure.
Solution Approach 2:
The shaft segments are designed with dynamic freedom to rotate relative to one another about the radial axis, allowing the structure to adapt to varying load conditions. This dynamic capability prevents binding under heavy loads while maintaining structural integrity, resolving the contradiction between simplicity and reliability.
2Ease of operation
If a rigid fixed connection is used between shaft segments, then manufacturing is easier, but ease of operation deteriorates due to binding under load
Solution Approach 1:
The shaft segments are pre-configured with spherical bearings and universal joints during manufacturing, which are designed to accommodate relative rotation. This preliminary preparation allows the segments to be easily assembled and ensures smooth operation during use, as the rotation capability is built into the structure before installation.
Solution Approach 2:
Spherical bearings and universal joints serve as intermediary elements between shaft segments, enabling smooth relative rotation while maintaining structural connection. These intermediaries facilitate ease of operation by preventing binding, while their standardized design keeps manufacturing and assembly complexity manageable.
3Reliability
If seals are added to prevent leakage, then reliability improves, but device complexity increases
Solution Approach 1:
The seal elements are integrated with the shaft segments and bearing structures, combining multiple functions into unified components. This merging approach prevents leakage to improve reliability while avoiding the need for separate, complex sealing systems, thereby limiting the increase in overall device complexity.
4Productivity
If variable geometry capabilities are added to nozzles, then efficiency over range of conditions improves, but constructability and installation deteriorate
Solution Approach 1:
The variable nozzle system is divided into modular segments that can be independently manufactured and then assembled. This segmentation allows each component to be optimized and constructed separately, improving overall constructability while maintaining the variable geometry capabilities that deliver efficiency across a wide range of operating conditions.
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 enhances the durability and constructability of variable nozzle assemblies, improves installation, and reduces variability in output, ensuring continued rotation and efficient operation under heavy loads while minimizing fluid leakage.
Implementation Method 1
connecting the first segment to the downstream outer platform by loading a first bearing about the protruding spherical shaped section of the outer stem
Implementation Method 2
linking segments of the segmented shaft via a casing opening
Data Source
AI summary
A method for constructing a variable nozzle assembly within a turbine engine that includes: constructing a variable nozzle sub-assembly; attaching the variable nozzle sub-assembly to a casing; and linking segments of a segmented shaft via an opening. Constructing the variable nozzle sub-assembly may include: attaching a downstream inner platform to a upstream inner platform; inserting an outer stem of a first segment through an outer stem opening formed through the downstream outer platform; connecting the first segment to the downstream outer platform by loading a first bearing about a protruding spherical shaped section of the outer stem; inserting the inner stem through an opening formed through the downstream inner platform while aligning sidewalls of the downstream and upstream outer platforms; mechanically securing the aligned sidewalls; and connecting the first segment to the downstream inner platform by loading a second bearing about a protruding spherical shaped section of the inner stem.