Turbofan Inlet Flow Effectors for Thermal Anti-Ice Failure

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Solution Overview

Problem

Existing turbofan engine inlets face structural failure due to excessive heating from engine anti-ice system failures, which static flow effectors fail to adequately address, leading to ice accumulation and increased fan noise.

Innovation Solution

Movable flow effectors, such as bi-metallic materials, wax motors, or piezoelectric actuators, transition between retracted and extended positions based on temperature thresholds to create turbulent flow and enhance cooling during EAI failures, while maintaining laminar flow during normal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the engine anti-ice system delivers heated air to the turbofan inlet, then ice formation on the inlet is prevented, but excessive heating can occur leading to structural failure of the inlet structures

Engineering Contradiction:
Improveice formation on inletVSAvoidinternal temperature of inlet structures
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The flow effectors are designed to dynamically change position based on temperature conditions. During normal EAI operation, they remain retracted to maintain laminar flow. When excessive temperature is detected, they extend to create turbulent flow and enhance cooling, providing a dynamic response to changing thermal conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the flow regime parameter from laminar to turbulent by extending the flow effectors. This parameter change alters the cooling characteristics of the inlet, enabling enhanced heat dissipation when temperatures exceed safe operating limits

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If static flow effectors are used in the turbofan inlet, then ice accumulation is reduced, but fan noise increases due to flow distortion

Engineering Contradiction:
Improveice accumulationVSAvoidfan noise
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The flow effectors transition from a static configuration to a dynamic one, remaining retracted during normal operation to avoid noise generation, and extending only when needed for ice prevention or excessive cooling, thus minimizing their impact on fan noise

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The flow effectors are positioned to be self-adjusting based on flow conditions, reducing the need for external control systems while maintaining their ice-prevention function without continuous noise generation

Inventive Principle:
Principle #25Self-service

3Temperature

If flow effectors are extended to create turbulent flow for cooling, then cooling efficiency improves, but device complexity increases

Engineering Contradiction:
Improvecooling efficiency of inletVSAvoidcomplexity of flow control device
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The flow effectors are designed to respond automatically to temperature or flow conditions without requiring external sensors, control systems, or power sources. The effectors self-actuate based on the physical conditions in the inlet, reducing system complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system utilizes natural parameter changes in the flow field to trigger the extension of flow effectors, leveraging physical phenomena rather than complex electronic control to achieve the desired cooling effect

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

Prevents structural failure and ice accumulation, reduces fan noise, and improves cooling efficiency during engine anti-ice system failures without additional certification issues.

Implementation Method 1

Movable flow effectors, such as bi-metallic materials, wax motors, or piezoelectric actuators, transition between retracted and extended positions based on temperature thresholds

Methodology Applied
Scientific EffectBi-metallic material thermal response: Bi-Metallic Strip

Implementation Method 2

Movable flow effectors, such as bi-metallic materials, wax motors, or piezoelectric actuators, transition between retracted and extended positions based on temperature thresholds

Methodology Applied
Scientific EffectWax motor thermal expansion: Thermal Expansion

Implementation Method 3

Movable flow effectors, such as bi-metallic materials, wax motors, or piezoelectric actuators, transition between retracted and extended positions based on temperature thresholds

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 4

transition from a retracted position to an extended position on the second side of the inlet surface in response to an ambient temperature on the first side of the inlet surface exceeding a first threshold

Methodology Applied
Scientific EffectTurbulent flow: Turbulence

Data Source

PatentEP4711598A1Thermally activated flow control device
Publication Date: 2026.03.18 THE BOEING CO
  • EP4711598A1 patent drawingFigure 1
  • EP4711598A1 patent drawingFigure 2
  • EP4711598A1 patent drawingFigure 3~4

AI summary

Systems, apparatuses and methods can provide for technology includes a turbofan engine subassembly having an inlet surface with a first side and a second side, and one or more flow effectors coupled to the inlet surface, wherein the flow effector(s) transition from a retracted position to an extended position on the second side of the inlet surface in response to an ambient temperature on the first side of the inlet surface exceeding a first threshold. The flow effector(s) may also transition from the extended position to the retracted position in response to the ambient temperature on the first side of the inlet surface falling below a second threshold.