Variable Flowpath Wall Assembly for Turbofan Tip-Speed Control

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Solution Overview

Problem

Existing turbofan engine flowpath geometries with fixed peripheral boundaries fail to optimize engine performance across various operating modes, necessitating a compromise in performance.

Innovation Solution

Incorporation of an inflatable bladder with a deformable face skin and an actuation system, including an air system and mechanical actuators, to dynamically adjust the flowpath geometry by inflating or deflating the bladder and mechanically deforming the face skin, allowing for adaptable geometry changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fixed peripheral boundaries are used in flowpath geometry, then structural simplicity and manufacturing ease are maintained, but engine performance cannot be optimized across various operating modes

Engineering Contradiction:
Improveengine performance optimizationVSAvoidflowpath geometry
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by transforming the static fixed peripheral boundaries into dynamic adjustable boundaries. The flowpath geometry is made variable through movable walls and adjustable geometric parameters, allowing the engine to adapt its flowpath configuration to different operating modes and optimize performance across various conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by enabling modification of key geometric parameters such as flowpath radius, wall positions, and cross-sectional dimensions. These parameters can be adjusted dynamically to change the flowpath geometry, allowing optimization of engine performance for different operating conditions without requiring complete redesign of the structure.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If fixed flowpath geometry is used, then manufacturing precision is easier to maintain, but propulsor section efficiency cannot be optimized for varying rotor blade tip speeds

Engineering Contradiction:
Improvepropulsor section efficiencyVSAvoidflowpath geometry
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent makes the flowpath geometry dynamic by incorporating movable walls and adjustable components that can change the flowpath configuration during operation. This allows the propulsor section efficiency to be optimized for varying rotor blade tip speeds by adjusting the flowpath geometry to match different operating conditions, while the manufacturing process maintains precision through controlled adjustment mechanisms.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If adaptable flowpath geometry is implemented, then engine performance is optimized, but device complexity increases

Engineering Contradiction:
Improveflowpath geometryVSAvoidactuation system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing actuation mechanisms that can serve multiple functions - adjusting different geometric parameters, controlling various sections of the flowpath, and adapting to different operating modes. This multi-functionality reduces the overall complexity by consolidating control capabilities into integrated systems rather than separate mechanisms for each adjustment.

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

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

Enhances engine performance by optimizing propulsor section efficiency and thrust generation across varying rotor blade tip speeds, facilitating improved aero loading and Mach number management.

Implementation Method 1

The air system is configured to regulate air pressure within the interior volume to deform the deformable face skin and change a geometry of the exterior surface

Methodology Applied
Scientific EffectAir pressure: Pressure Increase

Implementation Method 2

The actuator is configured to mechanically apply a force to the deformable face skin to further change the geometry of the exterior surface

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP4628706A1Assemblies for aircraft propulsion systems
Publication Date: 2025.10.08 RTX CORP
  • EP4628706A1 patent drawingFigure 1
  • EP4628706A1 patent drawingFigure 2
  • EP4628706A1 patent drawingFigure 3A

AI summary

An assembly is provided for an aircraft propulsion system. This assembly includes a flowpath wall (98) and an actuation system (146). The flowpath wall (98) includes an inflatable bladder (104) with a deformable face skin (106) and an interior volume (110). The deformable face skin (106) includes an exterior surface that forms a peripheral boundary of a flowpath (76) along the flowpath wall (98). The interior volume (110) extends within the inflatable bladder (104) to the deformable face skin (106). The actuation system (146) includes an air system (116) and an actuator (132). The air system (116) is fluidly coupled to the interior volume (110). The air system (116) is configured to inflate or deflate the inflatable bladder (104) to change a geometry of the exterior surface. The actuator (132) is disposed in the interior volume (110). The actuator (132) is configured to mechanically apply a force to the deformable face skin (106) to further change the geometry of the exterior surface.