Compressor Air Bleed Duct Routing for Variable Pitch Systems

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Solution Overview

Problem

In turbojet engines, the presence of variable-pitch systems on the outer casing makes it difficult to accommodate both air bleed manifolds and their associated ducts, resulting in a limited footprint for housing equipment and accessories.

Innovation Solution

An arrangement of air bleed circuits with intersecting duct sections and an adapter piece that allows separate and non-mixing flow paths for air from moving and fixed blades, enabling efficient air collection and transport while maintaining a compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If air bleed manifolds and ducts are installed on the outer casing, then air collection from compressor blades is improved, but the available space for variable-pitch systems and other equipment is reduced

Engineering Contradiction:
Improveair collection efficiencyVSAvoidavailable space on outer casing
Core Design Contradiction:
Quantity of substanceVSArea of stationary object

Solution Approach 1:

The patent transitions from a two-dimensional planar arrangement of manifolds on the outer casing to a three-dimensional configuration where ducts traverse through the compressor structure. The ducts pass through the moving bladed wheel and fixed bladed wheel assemblies, utilizing the radial and axial dimensions to route air bleed paths without occupying additional circumferential space on the outer casing surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The air bleed ducts are nested within the existing compressor structure by routing them through the hollow centers of the moving and fixed bladed wheel assemblies. The ducts are positioned concentrically within the radial structure of the compressor stages, effectively utilizing the internal volume of existing components rather than adding external attachments.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If variable-pitch systems are installed on the outer casing, then compressor stage adaptability is improved, but the space available for air bleed manifolds is reduced

Engineering Contradiction:
Improvecompressor stage adaptabilityVSAvoidspace for air bleed manifolds
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The air bleed system utilizes the radial and axial dimensions by routing ducts through the depth of the compressor assembly rather than occupying circumferential space. This dimensional transition allows variable-pitch mechanisms to be positioned on the outer casing while air bleed ducts traverse internally through the compressor stages.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The air bleed system is segmented into separate collection points for moving blade air bleed and fixed blade air bleed, with dedicated ducts for each. This segmentation allows independent routing paths that can be optimized to avoid interference with variable-pitch systems while maintaining effective air collection from both blade types.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If separate air bleed circuits for moving and fixed blades are implemented, then air flow control precision is improved, but device complexity increases

Engineering Contradiction:
Improveair flow control precisionVSAvoidcircuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The air bleed system is divided into separate circuits: one circuit collects air from the moving bladed wheel through dedicated orifices and ducts, while another circuit collects air from the fixed bladed wheel through separate orifices and ducts. This segmentation enables independent control and measurement of air flow from each blade type, improving precision while maintaining manageable complexity through modular design.

Inventive Principle:
Principle #1Segmentation

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

This solution allows for the simultaneous operation of air bleed systems and variable-pitch systems, optimizing space usage and enabling the placement of additional equipment on the compressor periphery, while maintaining efficient air flow and reduced size requirements.

Implementation Method 1

said adapter piece comprising a first section of duct forming a first flow path from said moving wheel manifold to a first outlet, said first section of duct and said second section of duct having respective directions which intersect

Methodology Applied
Scientific EffectFluid flow through ducts:

Data Source

PatentEP1959145B1Arrangement of air intake circuits for a compressor stage
Publication Date: 2017.08.02 SAFRAN AIRCRAFT ENGINES SAS
  • EP1959145B1 patent drawingFigure 1
  • EP1959145B1 patent drawingFigure 2~3
  • EP1959145B1 patent drawingFigure 4~5

AI summary

The arrangement has a rotor wheel controller (24) controlling air flow aspired on a revolving blade (8), and a stator wheel controller controlling the air flow aspired on a stator blade (9). The controller (24) is disposed on periphery of a compressor based on a rotor wheel (10), and the stator wheel controller is superimposed to the collector (24). Connecting tubes (32) are connected to the periphery of the compressor based on a stator wheel (12) and the stator wheel controller.