Curved Air Guide Tubes Reduce Pressure Loss in Turbine Rotors

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Solution Overview

Problem

Conventional air guiding devices in turbomachines suffer from high pressure losses and inefficient cooling due to vortex formation and suboptimal flow guidance, which affects the efficiency and cooling of turbine components.

Innovation Solution

A rotor with an air guiding device featuring air guiding tubes with inflow areas oriented in the direction of rotation, integrated with a support ring, and valve devices activated by centrifugal force, which reduces pressure losses and enhances flow guidance and stability, allowing for adjustable cooling air flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional radial tubes are used to guide cooling air, then air can be drawn radially inwards from an annular space, but high pressure losses occur due to vortex formation and suboptimal flow guidance

Engineering Contradiction:
Improvepressure lossesVSAvoidflow guidance efficiency
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The air guiding tubes are curved in the direction of rotation rather than being straight radial tubes. This curvature aligns the flow path with the rotational direction, reducing vortex formation and pressure losses while improving flow guidance efficiency throughout the tube length

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The inflow areas are oriented in the direction of rotation rather than radially inward. This parameter change in flow direction at the inlet reduces turbulent entry and vortex formation, thereby reducing pressure losses while maintaining effective cooling air guidance

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the air guiding device is designed with simple radial tubes, then the structure is simple, but vortex formation occurs leading to reduced cooling efficiency

Engineering Contradiction:
Improvestructural simplicityVSAvoidcooling efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The air guiding tubes are designed with curvature in the direction of rotation instead of simple straight radial configuration. This curved geometry suppresses vortex formation and improves cooling efficiency while remaining manufacturable through conventional or additive processes

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The air guiding device is divided into multiple individual air guiding tubes distributed around the rotor shaft. Each tube can be independently designed with optimal curvature and inflow orientation, allowing for improved cooling efficiency while maintaining manufacturing simplicity through modular production

Inventive Principle:
Principle #1Segmentation

3Reliability

If cooling air flow is increased to improve cooling, then cooling efficiency improves, but pressure losses increase

Engineering Contradiction:
Improvecooling efficiencyVSAvoidpressure losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The curved air guiding tubes in the direction of rotation reduce flow separation and vortex formation, allowing higher cooling air flows to be maintained with reduced pressure losses compared to straight radial tubes

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

Orienting the inflow areas in the direction of rotation reduces entry losses and creates more favorable flow conditions throughout the tubes. This parameter change enables more efficient use of cooling air, reducing the pressure penalty associated with high cooling air flows

Inventive Principle:
Principle #35Parameter changes

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

The solution significantly reduces pressure losses, improves cooling efficiency, and optimizes ventilation in turbomachines by minimizing vortex formation and stabilizing the air flow, leading to improved thermal management and mechanical resilience.

Implementation Method 1

the formation of high-loss vortices is almost completely or completely suppressed on the inlet side

Methodology Applied
Scientific EffectVortex formation: Vortex Ring

Implementation Method 2

the flow pattern and thus the flow guidance of the cooling air into the air guide tubes is improved

Methodology Applied
Scientific EffectFlow guidance:

Implementation Method 3

the at least one valve device can be activated by centrifugal force, it being possible for the at least one air guide tube to be opened or closed at high speeds

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 4

The calmed flow within the air-guiding tubes results in a reduced pressure loss on the outlet side

Methodology Applied
Scientific EffectPressure loss reduction: Pressure Drop

Data Source

PatentEP2617941B1Ventilation device and method for producing a ventilation device, rotor and fluid flow engine
Publication Date: 2019.03.13 MTU AERO ENGINES GMBH
  • EP2617941B1 patent drawingFigure 1
  • EP2617941B1 patent drawingFigure 2~3
  • EP2617941B1 patent drawingFigure 4~5

AI summary

The device (1) has air conduit tubes (14) for guiding air from an outer annular space radially toward a rotor shaft, and a support ring (12) for arranging the air conduit tubes in a radially closed intermediate space between two adjacent rotor disks. The support ring forms a radially inner boundary of the intermediate space in a mounted state of the device. The air conduit tubes comprise inflow regions (40) oriented in a rotation direction. The flowing regions are formed in an arc-shape and passes to a radial air conduit tube region i.e. neck region (42). An independent claim is also included for a method for manufacturing a ventilation device.