Aircraft Engine Entrained Particle Separation With Turning Duct Bleed Valves

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Solution Overview

Problem

Existing aircraft turbine engines face issues with entrained particles causing component erosion, corrosion, and clogging of cooling holes and passages, necessitating an improved system for particle removal.

Innovation Solution

A gas turbine engine design incorporating a turning duct assembly with axial and return segments to redirect airflow, coupled with bleed valves to selectively remove entrained particles, and a power turbine to utilize purged airflow for additional motive force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If particles are allowed to pass through the engine without removal, then the system complexity remains low, but component erosion, corrosion, and clogging occur

Engineering Contradiction:
Improvecomponent protection from erosion and corrosionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts harmful particles from the main airflow by introducing a separate particle removal system. The turning duct assembly diverts a portion of the compressed air to create a particle-concentrated stream that is separated from the clean airflow path, allowing particles to be removed without affecting the main engine operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary particle removal mechanism between the compressor and turbine sections. The turning duct assembly and associated valves act as intermediaries to intercept and remove particles before they reach critical turbine components, protecting them without requiring direct modification of the main gas path.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a particle removal system is implemented, then particle contamination is reduced, but the device complexity increases

Engineering Contradiction:
Improveparticle contaminationVSAvoidsystem complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The turning duct assembly serves multiple functions: it redirects compressed air for particle removal, maintains pressure differential for particle separation, and integrates with existing engine components. This multi-functionality reduces the need for additional dedicated particle removal devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the engine's own compressed air as the working fluid for particle removal, eliminating the need for external power sources or additional working fluids. The high-pressure air from the compressor automatically provides the force needed to drive particles into the turning duct and remove them from the clean airflow.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If airflow is redirected through turning duct segments, then particles are separated from the main flow, but pressure loss occurs

Engineering Contradiction:
Improveparticle separationVSAvoidpressure loss
Core Design Contradiction:
Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The system removes only a portion of the compressed air through the turning duct assembly, rather than redirecting the entire airflow. This partial action allows particle separation to occur in a controlled manner while minimizing the impact on overall engine pressure and performance.

Inventive Principle:
Principle #16Partial or excessive action

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

Effectively removes entrained particles upstream of critical engine components, preventing fouling and enhancing engine performance by leveraging airflow redirection and bleed valve mechanisms.

Implementation Method 1

The first return segment provides an arcuate passage from the FAS exit end to the SAS inlet end. The second return segment provides an arcuate passage from the SAS exit end to an inlet of the HPC.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

The first bleed valve is in fluid communication with the first return segment.

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP4579070A1Aircraft engine entrained particle separation system and method
Publication Date: 2025.07.02 RTX CORP
  • EP4579070A1 patent drawingFigure 1
  • EP4579070A1 patent drawingFigure 2
  • EP4579070A1 patent drawingFigure 3

AI summary

A gas turbine engine (22) is provided that includes a bypass duct (82), fan (32), compressor (34), combustor (36), and turbine (38) sections, a nozzle (40), a turning duct assembly (68), and a first bleed valve (106). The compressor section (34) includes a compressor inlet (84) and low and high pressure compressors (42, 44). The turning duct assembly (68) has first and second axial segments (86, 88) and first and second return segments (90,91). The first axial segment (86) is in fluid communication with the low pressure compressor (42) and the first return segment (90). The second axial segment (88) is in fluid communication with the first return segment (90) and the second return segment (91). The high pressure compressor (44) is in fluid communication with the second return segment (91). The first and second axial segments (86, 88) and the first and second return segments (90, 91) are configured to provide an airflow passage between the low and high pressure compressors (42, 44). The first bleed valve (106) is in fluid communication with the first return segment (90).