Aircraft Labyrinth Seal Cavities for Higher Tightness With Two Lips
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Solution Overview
Problem
Current labyrinth seals for turbomachines, which rely on rotating wipers and abradable elements, face limitations in achieving optimal tightness and efficiency due to the need for multiple wipers and complex gas flow management.
Innovation Solution
A simplified labyrinth seal design utilizing only two wipers with radially extending cavities and axial partitions that create 'bathtub' spaces for gas flow, enhancing turbulence and tightness by disturbing the gas flow multiple times as it passes through the seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple wipers are used to improve seal tightness, then the sealing performance improves, but the device complexity and number of components increase
Solution Approach 1:
The patent merges the functions of multiple wipers into a single wiper structure. This single wiper incorporates multiple lips that can contact the abradable element at different positions, combining the sealing functions of what would traditionally require multiple separate wipers. This reduces component count while maintaining the ability to create multiple flow disturbances for effective sealing
Solution Approach 2:
The wiper is segmented into multiple lips or sealing edges that contact the abradable element at different locations. This segmentation allows a single wiper to create multiple flow disturbances in the gas stream, achieving the sealing effect of multiple wipers through one divided component
2Reliability
If the radial clearance between wiper and abradable element is reduced to improve tightness, then the seal performance improves, but the risk of contact and wear increases
Solution Approach 1:
The abradable element is designed with localized soft or sacrificial material properties at specific contact zones, allowing controlled wear in predetermined areas. This enables the wiper to maintain very close radial clearance for high tightness while the abradable material absorbs wear damage, protecting the harder wiper structure from damage
3Reliability
If the number of wipers is increased to enhance turbulence and tightness, then the seal performance improves, but the manufacturing cost and assembly difficulty increase
Solution Approach 1:
Multiple sealing functions are merged into a single wiper assembly that can be manufactured and installed as one unit. The wiper incorporates multiple lips and the cavity structure with partitions in a unified design, eliminating the need to assemble multiple separate wiper components, thereby simplifying manufacturing and installation while achieving enhanced turbulence through multiple flow disturbances
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
Significantly improves the seal's tightness by creating multiple disturbances in the gas flow, reducing radial clearances and increasing turbulence, thus enhancing the overall performance of the seal.
Implementation Method 1
the wipers 12 have the function of disturbing the flow of gas which tries to flow between the elements 14, 16 from upstream to downstream, that is to say from left to right in the drawings. This creates turbulence in the gas flow which generates pressure drops and thus improves the tightness of the joint.
Implementation Method 2
This creates turbulence in the gas flow which generates pressure drops and thus improves the tightness of the joint.
Data Source
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AI summary
The invention relates to a labyrinth sealing joint (100) for a turbomachine, in particular of an aircraft, comprising a rotor element (114) extending about an axis (A), and a stator element (116) extending around the rotor element (114), the rotor element (114) comprising two annular lips (112a, 112b) extending radially outwards and surrounded by at least one abradable element (118) carried by said stator element (116). The invention is characterized in that a plurality of gas passage cavities are arranged circumferentially next to one another between the two lips (112a, 112b) which are interconnected by connecting partitions, and in that at least one of said lips (112a, 112b) comprises at least one axial gas passage opening that leads into at least some of said cavities.