Turbine Root Spacer Gap Design for Shock Absorption

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Solution Overview

Problem

Existing rotor spacers in turbine engines do not effectively manage stress and rotation during normal operation and foreign object collisions, leading to potential engine damage and failure.

Innovation Solution

A rotor assembly design featuring a root spacer with radially extending side surfaces that engage the root base segment and side segments, allowing for a gap with the rotor disk, which supports the root during normal operation and enables rotation and shock absorption during collisions by pivoting within the slot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a root spacer is used to fill the gap between the root and rotor disk, then slippage and wear are reduced during low centrifugal loading, but internal stresses increase when foreign objects collide with the fan blade

Engineering Contradiction:
Improvereduction of slippage and wearVSAvoidinternal stresses on fan blade
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The root spacer incorporates a gap between its outer surface and the rotor disk, creating a localized region that allows stress relief while maintaining engagement with the root base segment. This local modification enables the spacer to reduce wear during normal operation while accommodating shock loads during collisions without transmitting full internal stresses to the fan blade.

Inventive Principle:
Principle #3Local quality

2Reliability

If the root spacer creates a rigid connection between the rotor disk and fan blade, then slippage is reduced, but the fan blade cannot absorb shock loads effectively during collisions

Engineering Contradiction:
Improvereduction of slippageVSAvoidshock absorption capability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The root spacer design transitions from a fully rigid connection to a dynamic system where the gap between the spacer's outer surface and the rotor disk allows controlled movement. During normal operation, the spacer maintains engagement to prevent slippage, but during collision events, the gap enables the fan blade to pivot and rotate slightly, allowing the structure to absorb shock loads dynamically rather than transmitting rigid forces.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If the root spacer engages the root base segment with its outer surface, then rotational stability is improved, but the fan blade loses the ability to rotate and absorb shock during collisions

Engineering Contradiction:
Improverotational stabilityVSAvoidability to rotate and absorb shock
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The root spacer features a specifically designed gap between its outer surface and the rotor disk, creating a localized region that permits controlled rotation and movement. This local modification maintains engagement with the root base segment for rotational stability during normal operation, while the gap provides the necessary adaptability for the fan blade to rotate and absorb shock loads during collision events.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2935785B1Root spacer for arranging between a rotor disk and a root of a rotor blade
Publication Date: 2019.03.27 UNITED TECH CORP
  • EP2935785B1 patent drawingFigure 1
  • EP2935785B1 patent drawingFigure 2~3
  • EP2935785B1 patent drawingFigure 4

AI summary

A rotor assembly is provided that includes a rotor blade, a root spacer, and a rotor disk with a slot. The rotor blade includes a blade root arranged within the slot. The blade root includes a root base segment and a pair of root side segments. The root base segment is laterally separated from the rotor disk by the root side segments. The root spacer is arranged within the slot, and includes a side surface that extends radially between an inner surface and an outer surface. The side surface is approximately laterally aligned with an intersection between the root base segment and a first of the root side segments. The outer surface engages the root base segment.