Thermal Flow Effectors for Turbofan Inlet Overheat Cooling

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Solution Overview

Problem

Existing turbofan engine inlets face structural failure due to excessive heating during 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 ambient 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 inlet, then ice formation on the inlet is prevented, but the internal temperature of the inlet structures can exceed normal operating temperatures leading to structural failure

Engineering Contradiction:

Improveice formation on inletVSAvoidinternal temperature of inlet structures

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

The flow effector transitions from a static component to a dynamic one that can change position based on temperature conditions. It moves from a retracted position (normal operation) to an extended position (overtemperature condition) to alter airflow characteristics and provide cooling to the inlet structure.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention converts the harmful overtemperature condition into a beneficial cooling effect. When the temperature exceeds the threshold, the extended flow effector creates turbulent flow that enhances heat transfer and cools the inlet structure, turning the harmful thermal condition into a trigger for active cooling.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If static flow effectors are used in the inlet, then ice accumulation is addressed, but fan noise increases and certification issues arise

Engineering Contradiction:

Improveice accumulationVSAvoidfan noise

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The flow effector is designed to be movable rather than static, allowing it to adapt to different operating conditions. During normal operation, it remains retracted and does not interfere with airflow, thus avoiding noise generation. During overtemperature conditions, it extends to provide cooling functionality.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The flow effector is equipped with a thermal sensor and control system that enable it to autonomously detect overtemperature conditions and transition to the extended position without external intervention. This self-regulating capability eliminates the need for continuous mechanical actuation and reduces noise.

Inventive Principle:

Principle #25Self-service

3Temperature

If the flow effector transitions to extended position during overtemperature, then cooling efficiency improves, but device complexity increases

Engineering Contradiction:

Improvecooling efficiency of inlet structureVSAvoidcomplexity of flow control device

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The invention replaces complex mechanical actuation systems with a thermal-responsive mechanism. The flow effector uses a thermal sensor and control system that automatically trigger the transition to the extended position, eliminating the need for external actuators, linkages, and control mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The flow effector's position is changed in response to a temperature parameter threshold. When the temperature exceeds the predetermined threshold, the effector transitions from retracted to extended position. This parameter-based control simplifies the system by using the existing thermal field as the control signal.

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

Implementation Method 1

one or more flow effectors are to transition from a retracted position to an extended position on the second side of the lip skin surface in response to an ambient temperature on the first side of the fan cowl surface exceeding a first threshold

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the one or more flow effectors are to transition from a retracted position to an extended position... to create turbulent flow and enhance cooling

Methodology Applied

Scientific EffectTurbulence: Turbulence

Data Source

PatentUS12540561B1Thermally activated flow control device

Publication Date: 2026.02.03 THE BOEING CO

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.