Hybrid Rotor with Solid and Hollow Blades for Gas Turbines

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Solution Overview

Problem

Conventional gas turbine engines face challenges with mistuned blades in integrally bladed rotors, which reduce aerodynamic efficiency and complicate machining, while mechanically bladed rotors suffer from increased stress and limited machinability due to reduced rotor disk material.

Innovation Solution

A hybrid rotor design incorporating both solid and hollow rotor blades, with each type independently tuned to respond differently at the engine stability pinch point, and mechanically retained in a hybrid configuration that allows for easier repair and reduced stress, using different materials for varying fatigue resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mistuned blades are used in integrally bladed rotors, then vibratory response is reduced, but aerodynamic efficiency is reduced

Engineering Contradiction:

Improvevibratory responseVSAvoidaerodynamic efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating zones of different blade tuning characteristics within the rotor. Specifically, it uses a hybrid configuration where some blades are tuned to a first frequency and other blades are tuned to a second frequency, allowing different local regions to have optimized properties for their specific functional requirements.

Inventive Principle:

Principle #3Local quality

2Strength

If integrally bladed rotor design is used, then structural integrity is improved, but machining difficulty increases due to limited space between blades

Engineering Contradiction:

Improvestructural integrityVSAvoidmachining difficulty

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent applies segmentation by dividing the rotor blade structure into multiple tunable segments or groups. Instead of treating all blades as a single integral unit, the rotor is configured with distinct blade sets that can be independently tuned, allowing for modular manufacturing approaches while maintaining overall structural integrity.

Inventive Principle:

Principle #1Segmentation

3Weight of moving object

If mechanically bladed rotor design is used with reduced rotor disk material, then weight is reduced, but fan blade pull load increases

Engineering Contradiction:

Improverotor weightVSAvoidfan blade pull load

Core Design Contradiction:

Weight of moving objectVSForce

Solution Approach 1:

The patent applies composite materials by combining different blade tuning configurations within the same rotor structure. This hybrid approach integrates blades with different frequency characteristics, allowing the rotor to achieve weight reduction while distributing stress more effectively through the varied blade responses.

Inventive Principle:

Principle #40Composite materials

4Ease of repair

If mechanically bladed rotor design is used, then blade replacement is easier, but rotor disk stress increases

Engineering Contradiction:

Improveblade replacementVSAvoidrotor disk stress

Core Design Contradiction:

Ease of repairVSStress or pressure

Solution Approach 1:

The patent applies local quality by creating distinct zones with different blade configurations. The mechanically retained blades are positioned in specific circumferential zones where they can be independently replaced, while the integrally bladed zones provide structural support, thereby localizing the repair capability without compromising overall stress distribution.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10954804B2Rotary machines including a hybrid rotor with hollow and solid rotor blade sets

Publication Date: 2021.03.23 RTX CORP

AI summary

A hybrid rotor may comprise a rotor disk having a peripheral rim, a plurality of solid rotor blades extending outwardly from the rotor disk, and a plurality of hollow rotor blades extending outwardly from the rotor disk in a blade array with the plurality of solid rotor blades. In various embodiments, the plurality of solid rotor blades may be integrally coupled to the rotor disk. In various embodiments, the plurality of hollow rotor blades may be mechanically retained in the rotor disk.