Aircraft Thrust Recovery Outflow Valve Aerodynamic Design

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Solution Overview

Problem

Conventional outflow valves in aircraft cabin pressurization systems generate noise and reduce thrust recovery due to noise suppression mechanisms that alter airflow patterns, resulting in inefficient thrust recovery and increased drag.

Innovation Solution

The thrust recovery outflow valve is designed with an aerodynamic convergent-divergent profile and orientation to align the thrust vector parallel to the aircraft's direction of flight, maximizing thrust recovery efficiency by directing exhausted air aft and using side plates to prevent lateral exit, thus reducing drag and fuel burn.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If noise suppression mechanisms are added to outflow valves, then noise levels are reduced, but thrust recovery efficiency decreases and drag increases

Engineering Contradiction:
ImprovenoiseVSAvoidthrust recovery efficiency
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent removes noise suppression mechanisms from the outflow valve system entirely. By extracting these harmful components, the invention eliminates the interference they cause to airflow patterns, thereby restoring optimal thrust recovery efficiency while managing noise through alternative means such as aerodynamic design of the exhaust plume.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the previously harmful direct exhaust flow into a beneficial force by precisely orienting the outflow valve to align the thrust vector with the aircraft's direction of flight. The exhaust plume, which would normally create drag, is now directed to provide forward thrust, converting a harmful effect into a beneficial propulsive force.

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

2Reliability

If conventional outflow valves are used, then cabin pressurization is maintained, but thrust recovery is reduced and drag is increased

Engineering Contradiction:
Improvecabin pressurization controlVSAvoiddrag
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The outflow valve is designed with adjustable orientation capabilities, allowing the thrust vector direction to be dynamically optimized. The valve can be positioned at specific angles relative to the aircraft's longitudinal axis to align the exhaust flow with the direction of flight, converting drag into thrust while maintaining cabin pressurization control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the orientation parameter of the outflow valve to optimize thrust recovery. By adjusting the valve's angular position and alignment, the exhaust flow direction is modified to match the aircraft's flight path, transforming the harmful drag effect into beneficial forward thrust while preserving the essential cabin pressurization function.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If noise suppressors are installed, then acoustic tones are suppressed, but airflow patterns are disturbed and momentum is lost

Engineering Contradiction:
Improveacoustic noiseVSAvoidairflow momentum
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

The patent extracts and removes noise suppressor components from the outflow valve assembly. By eliminating these devices that interfere with airflow, the system preserves the natural momentum and directional integrity of the exhaust plume, allowing it to provide effective thrust recovery without acoustic suppression mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

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 design increases thrust recovery efficiency by 10% compared to conventional valves, reducing drag and fuel consumption while maintaining acceptable noise levels without noise suppressors, enhancing aircraft performance and efficiency.

Implementation Method 1

The thrust recovery outflow valve is designed with an aerodynamic convergent-divergent profile and orientation to align the thrust vector parallel to the aircraft's direction of flight

Methodology Applied
Scientific EffectAerodynamic profile: Aerofoil

Implementation Method 2

maximizing thrust recovery efficiency by directing exhausted air aft and using side plates to prevent lateral exit, thus reducing drag and fuel burn

Methodology Applied
Scientific EffectThrust recovery: Jet

Data Source

PatentEP3225553B1Thrust recovery outflow valves for use with aircraft
Publication Date: 2021.11.17 THE BOEING CO
  • EP3225553B1 patent drawingFigure 1
  • EP3225553B1 patent drawingFigure 2
  • EP3225553B1 patent drawingFigure 3~4

AI summary

Thrust recovery outflow valves (200) for aircraft are disclosed. An example thrust recovery outflow valve (200) includes a flow control member (216) having a first aerodynamic surface (230) and a second aerodynamic surface (246) to define at least a portion of a fluid flow passageway between an inlet (204) and an outlet (208) of the thrust recovery outflow valve (200). A first portion (422) of the first aerodynamic surface (230) and a first portion (434) of the second aerodynamic surface (246) provides a converging profile between the inlet (204) and a throat (408) of the fluid flow passageway. A second portion of the first aerodynamic surface (230) and a second portion of the second aerodynamic surface (246) provides a diverging profile between the throat (408) and the outlet (208) of the fluid flow passageway. The fluid flow passageway is positioned at a small angle relative to an outer surface (412) of an aircraft to enable fluid exiting the fluid flow passageway to provide a thrust recovery vector (416) oriented substantially parallel to the outer surface (412) of the aircraft and opposite a direction of drag.