Aircraft Rotor Disk Lip Geometry for Leakage Control and Braking

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Solution Overview

Problem

Existing air leakage restrictor arrangements in aircraft powerplants between rotor disks and stationary structures have room for improvement in terms of efficiency and failure modes, particularly in managing air leakage and shaft failure scenarios.

Innovation Solution

The implementation of a bladed rotor and stationary structure design where the rotor disk and stationary structure surfaces have matching concave and convex curvatures, forming a controlled air gap during normal operation and a line contact during shaft failure to minimize wear and facilitate braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a gap is maintained between the rotor disk and stationary structure during normal operation, then air leakage is controlled efficiently, but the structure cannot provide braking function during shaft failure

Engineering Contradiction:

Improveair leakage controlVSAvoidshaft failure response

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The air gap arrangement is designed to be dynamic rather than static. During normal operation, the rotor disk and stationary structure are separated by a controlled gap to minimize air leakage. During shaft failure, the rotor disk can contact the stationary structure along a line contact to provide braking function. This dynamic adaptability resolves the contradiction between maintaining air leakage control and providing failure response.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The stationary structure with convex curvature is designed to serve multiple functions: (1) forming a controlled air gap with the rotor disk during normal operation to control air leakage, and (2) providing a line contact braking surface during shaft failure. This multi-functionality resolves the contradiction by making the same structure effective for both air leakage control and failure response.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the rotor disk contacts the stationary structure during shaft failure, then braking function is provided, but wear increases due to contact

Engineering Contradiction:

Improvebraking functionVSAvoidcomponent wear

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

Both the rotor disk and stationary structure are designed with matching concave and convex curvatures. This curved surface design creates a line contact rather than a point contact during shaft failure, distributing the braking force along the line of contact. This reduces localized wear and extends component life while maintaining effective braking function.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The contact between rotor disk and stationary structure during shaft failure, which would normally cause wear and damage, is converted into a beneficial braking mechanism. The matching curvatures ensure that the contact occurs along a controlled line, transforming the harmful wear effect into a useful friction-based braking function that safely stops the rotor.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Duration of action of stationary object

If matching curvatures are used between rotor disk and stationary structure, then line contact is achieved reducing wear, but manufacturing precision requirements increase

Engineering Contradiction:

Improvewear reductionVSAvoidcurvature matching

Core Design Contradiction:

Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The use of matching concave and convex curvatures creates a line contact interface that is more tolerant to manufacturing variations compared to point contact. The curved surfaces naturally accommodate minor deviations and still achieve effective line contact, reducing wear while maintaining feasible manufacturing precision requirements.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS20260063044A1Air leakage restrictor arrangement for an aircraft powerplant

Publication Date: 2026.03.05 PRATT & WHITNEY CANADA CORP

AI summary

An assembly is provided for an aircraft powerplant. This powerplant assembly includes a bladed rotor and a stationary structure. The bladed rotor is rotatable about an axis. The bladed rotor includes a rotor disk and a plurality of rotor blades. The rotor disk includes a web and a rim with a concave disk surface at an inside corner between the web and the rim. The concave disk surface has a disk surface sectional geometry in a reference plane parallel with the axis. The rotor blades are arranged circumferentially around and project radially out from the rim. The stationary structure includes a lip with a convex lip surface. The convex lip surface is next to the concave disk surface. The convex lip surface has a lip surface sectional geometry in the reference plane that matches the disk surface sectional geometry.