Variable-Pitch Stator Blades Floating Ring Sealing
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Solution Overview
Problem
The existing turbomachine compressor designs with floating rings face challenges in reducing the internal diameter of the compressor passage due to bulky sealing means, which prevent efficient airflow increase and are difficult to implement effectively.
Innovation Solution
An annular stator part is interposed between the floating ring and the rotor, with calibrated air leak systems between the stator part and the rotor, and mechanical sealing means between the floating ring and the stator part, allowing for relative displacements and reduced bulkiness of sealing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bulky labyrinth seals are used between the floating ring and rotor to prevent air recirculation, then sealing effectiveness is improved, but the internal diameter of the compressor passage cannot be reduced
Solution Approach 1:
An annular stator part is introduced as an intermediary component between the floating ring and the rotor. This stator part carries the sealing means, separating the sealing function from the rotor and allowing the floating ring to be positioned closer to the rotor without direct bulky sealing between them. The stator part acts as a mediator that enables both effective sealing and reduced passage diameter.
Solution Approach 2:
The sealing arrangement is repositioned from a radial configuration (directly between floating ring and rotor) to an axial configuration (on the stator part between floating ring and rotor). By moving the sealing means to the stator part in the axial direction, the radial space requirements are reduced, allowing for a smaller internal diameter of the compressor passage.
2Reliability
If additional labyrinth seals are added near the bearing enclosure to prevent oil leaks, then oil sealing is improved, but device complexity increases
Solution Approach 1:
The stator part is designed to serve multiple functions: it supports the variable-pitch stator vanes, provides a mounting surface for sealing means to prevent air recirculation, and acts as a barrier to prevent oil leaks toward the bearing enclosure. By consolidating these functions into a single component, the need for separate sealing arrangements is reduced, simplifying the overall device structure.
3Productivity
If the internal diameter of the vein is reduced to increase airflow, then compressor productivity is improved, but the sealing means become more constrained and difficult to implement
Solution Approach 1:
The sealing system is segmented into two independent parts: one sealing arrangement on the stator part for preventing air recirculation, and another sealing arrangement on the bearing enclosure for preventing oil leaks. This segmentation allows each sealing system to be optimized independently and manufactured separately, making implementation easier even with reduced internal diameter constraints.
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 enables a reduction in the size of the floating ring, facilitating a decrease in its external diameter and an increase in airflow, while maintaining effective sealing to prevent oil leaks and air recirculation.
Implementation Method 1
The first sealing means comprise two labyrinth seals
Implementation Method 2
a labyrinth seal which comprises annular wipers carried by the rotor and cooperating with an annular layer of abradable material carried by the floating ring
Implementation Method 3
an annular cavity intended to be supplied with compressed air, this air being intended to flow upstream and downstream and to cross the two labyrinth seals defining the cavity, to prevent the passage of oil through these seals
Data Source
Figure 1~3
AI summary
The invention relates to a turbine engine compressor (10'), comprising at least one annular row of variable-pitch stator blades (12), wherein said blades are substantially radial and comprise pivots (22, 24) at the radial ends thereof, the radially external pivots of the blades being inserted in first openings of a stator housing (20) and the radially internal pivots being inserted in second openings of a floating ring (60) that surrounds a rotor (18) of the compressor, characterized in that an annular stator part (62) is inserted between the floating ring and the compressor rotor, and in that first sealing means are mounted between the stator part and the compressor rotor, and second sealing means are mounted between the floating ring and the stator component.