Swirl Recovery Vane Open Rotor Layout for Stable Core Inlet Flow

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Solution Overview

Problem

Traditional open rotor architectures with a core inlet located axially between the rotor blades and static vanes face challenges in balancing aerodynamic design for propulsive efficiency and compressor stability, particularly at high angles of attack, leading to non-uniform flow and potential disturbances.

Innovation Solution

The core inlet is positioned forward of the rotor, allowing the rotor root to pre-condition airflow for the low-pressure compressor, with a rotating frame between the rotor blades to facilitate airflow without interference, and incorporating variable pitch mechanisms to control airflow and thrust.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the core inlet is located axially between the rotor blades and static vanes (traditional configuration), then the aerodynamic design can be simplified, but the flow uniformity deteriorates and compressor stability worsens, especially at high angles of attack

Engineering Contradiction:
Improveaerodynamic design complexityVSAvoidcompressor stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent inverts the traditional core inlet location from between the rotor blades and static vanes to forward of the rotor. This inversion allows the rotor root to pre-condition the airflow before it enters the core, improving flow uniformity and compressor stability while maintaining manageable design complexity through the rotating frame mechanism

Inventive Principle:
Principle #13The other way round (Inversion)

2Stability of the object's composition

If the core inlet is positioned forward of the rotor, then compressor stability and flow uniformity improve, but the device complexity increases due to the rotating frame mechanism

Engineering Contradiction:
Improvecompressor stabilityVSAvoidrotating frame mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The rotating frame serves multiple functions simultaneously: it supports the inlet splitter, provides structural support for the rotor hub, and actively participates in airflow conditioning. This multi-functionality reduces the need for separate components, making the increased complexity worthwhile for the performance gains

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

Solution Approach 2:

The rotating frame and inlet splitter perform preliminary airflow conditioning before the air enters the core compressor. By pre-conditioning the flow in advance, the system achieves better compressor stability and flow uniformity, reducing the need for complex downstream adjustments

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If a rotating frame is introduced between the rotor hub and rotor blades, then airflow distribution is optimized, but the structural complexity increases

Engineering Contradiction:
Improveairflow distribution uniformityVSAvoidrotating frame structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The rotating frame is designed to rotate with the rotor, dynamically adapting its position relative to the rotor blades during operation. This dynamic configuration allows the frame to maintain optimal airflow paths across varying operating conditions, achieving superior airflow distribution uniformity despite the added structural complexity

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4647343A1Swirl recovery vane open rotor with core inlet forward of rotor
Publication Date: 2025.11.12 RTX CORP
  • EP4647343A1 patent drawingFigure 1A
  • EP4647343A1 patent drawingFigure 1B
  • EP4647343A1 patent drawingFigure 1C

AI summary

An aircraft propulsion system (20a) includes a rotor hub (76), rotor blades (78), a rotating frame (82), and a low-pressure compressor (39). The rotor hub (76) is configured to rotate about a central axis (22). The rotor blades (78) are arranged around the rotor hub (76). Each of the rotor blades (78) is configured to rotate about a radial axis of the rotor hub (76). The rotating frame (82) is positioned between the rotor hub (76) and the plurality of rotor blades (78). The rotating frame (82) is configured to allow air to pass without interference of the rotor blades (78). The low-pressure compressor (39) is configured to receive the air passing through the rotating frame (82).