Turbomachine Rotor Shroud Segmentation for Thermal Expansion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Turbine performance is reduced due to air bypassing the blades, and existing sealing systems face issues with radial clearance changes caused by differential expansion, leading to mechanical stresses and reduced lifespan.
Innovation Solution
A rotary assembly with a rotor shroud and stator ring that uses axial or oblique contact portions to decouple the radial expansion of rotor stages from the rotor shroud, allowing for controlled thermal expansion and reduced mechanical stresses, while maintaining effective sealing through wipers and abradable tracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the rotor blade tips are equipped with grooves to seal the flow, then air bypass is reduced, but radial clearance increases due to differential expansion, reducing sealing effectiveness
Solution Approach 1:
The rotor shell is segmented into multiple axial sections (first rotor shell section, second rotor shell section) that can expand independently. This segmentation allows each section to accommodate differential thermal expansion while maintaining the overall sealing function, preventing clearance increase despite temperature variations.
Solution Approach 2:
The invention changes the thermal expansion parameters of different rotor shell sections by using different materials or structures. The first rotor shell section has different expansion characteristics than the second section, allowing them to compensate for each other's expansion and maintain stable radial clearance at the blade tips.
2Manufacturing precision
If cold air is circulated along the outer wall to cool the turbine housing, then radial clearance is controlled, but a significant volume of fresh air is consumed
Solution Approach 1:
The rotor shell sections perform self-regulation of their radial dimensions through controlled thermal expansion. Each section expands or contracts based on its own temperature and material properties, automatically maintaining optimal clearance without requiring external cooling systems or additional air circulation.
Solution Approach 2:
The invention deliberately utilizes thermal expansion of the rotor shell sections rather than fighting it with cooling. The first and second rotor shell sections have different expansion characteristics that are designed to compensate for each other, transforming the thermal expansion problem into a solution that maintains clearance stability.
3Stability of the object's composition
If the rotor shell is rigidly connected to rotor stages, then structural stability is improved, but mechanical stresses increase due to differential expansion
Solution Approach 1:
The rotor shell is divided into multiple independent axial sections that are not rigidly connected to each other. This segmentation allows each section to expand and contract independently in response to thermal gradients, preventing the buildup of mechanical stresses while maintaining overall structural stability through the coordinated expansion of sections.
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 stabilizes the radial position of the rotor shroud, reduces air bypass, and extends the lifespan of the assembly by minimizing mechanical stresses, improving turbine performance and efficiency.
Implementation Method 1
Given the high and heterogeneous temperatures within the turbine, differential expansion of certain components can occur, altering the clearances between some parts
Implementation Method 2
the rotor blade tips are generally equipped with grooves designed to cut a track of abradable material carried by the stator
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a rotary assembly for a turbine engine, comprising a rotor with two consecutive rotor stages (10a, 10b) equipped with a plurality of movable vanes (20), and an annular rotor collar (50) connecting the two consecutive rotor stages; a stator comprising a stator stage (11), provided with a plurality of fixed vanes (30) and disposed between the two rotor stages, and an annular stator ring (60) mounted on the fixed vanes. Either the rotor collar or the stator ring bears at least one tab (51) designed to cooperate with an abradable track (62) on the other of the rotor collar and stator ring, such that the rotor collar comprises at at least one of its upstream or downstream ends an inclined contact portion (154) resting on an inclined bearing surface (173a) of the corresponding rotor stage, the bearing surface being the outer surface of a projection (173) extending from a base portion (127) of the corresponding rotor stage.