Aircraft Rotor Disk Lip Geometry for Air Leakage Restriction
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Solution Overview
Problem
Existing air leakage restrictor arrangements in aircraft powerplants do not adequately address the need for improved sealing and structural integrity during normal operation and failure modes, particularly in the interface between rotor disks and stationary structures.
Innovation Solution
The implementation of a bladed rotor with a concave disk surface and a matching convex lip surface in the stationary structure, forming a controlled air gap during normal operation and a line contact for braking during failure modes, ensuring minimal wear and effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gap is maintained between the rotor disk and stationary structure during normal operation, then air leakage is controlled and sealing is improved, but structural protection and braking capability during failure modes are reduced
Solution Approach 1:
The rotor disk surface is formed with a concave curvature and the stationary structure lip is formed with a matching convex curvature. These complementary curved surfaces create a labyrinth seal geometry that effectively restricts air leakage during normal operation while allowing contact during failure modes for structural protection and braking.
2Reliability
If the rotor disk and stationary structure are designed to contact during failure modes, then structural protection and braking are improved, but wear and damage during normal operation increase
Solution Approach 1:
The complementary concave and convex curved surfaces are designed to contact along a line rather than a point during failure modes. This line contact distributes the braking force and reduces localized wear, while the curved geometry ensures that contact only occurs when the gap closes during failure conditions, not during normal operation.
3Reliability
If a labyrinth seal configuration is used, then air leakage is restricted, but device complexity increases
Solution Approach 1:
The labyrinth seal functionality is merged with the structural components themselves. The concave disk surface and convex lip surface that form the air leakage restrictor are integrated into the rotor disk and stationary structure, respectively, rather than being separate seal components. This eliminates additional parts while maintaining effective sealing.
Data Source
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AI summary
An assembly is provided for an aircraft powerplant. This powerplant assembly includes a bladed rotor (40; 64) and a stationary structure (66). The bladed rotor (40; 64) is rotatable about an axis (68). The bladed rotor (40; 64) includes a rotor disk (70) and a plurality of rotor blades (72). The rotor disk (70) includes a web (82) and a rim (84) with a concave disk surface (106) at an inside corner (108) between the web (82) and the rim (84). The concave disk surface (106) has a disk surface sectional geometry in a reference plane parallel with the axis (68). The rotor blades (72) are arranged circumferentially around and project radially out from the rim (84). The stationary structure (66) includes a lip (146) with a convex lip surface (152). The convex lip surface (152) is next to the concave disk surface (106). The convex lip surface (152) has a lip surface sectional geometry in the reference plane that matches the disk surface sectional geometry.