Drained Fluid Evacuation Stub Using Dynamic Pressure

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Solution Overview

Problem

Existing aircraft propulsion units face challenges in managing drained fluids, as the limited retention box volume requires fluid discharge, which can lead to leaks on the ground due to the lack of a reliable drainage mechanism independent of engine computer control or pressure measurements.

Innovation Solution

A stub with a pressure-difference-measuring mechanism that uses dynamic pressure to autonomously initiate fluid discharge when the aircraft reaches a certain velocity, featuring a movable member that opens the discharge orifice when external dynamic pressure exceeds a predetermined threshold, preventing fluid release on the ground.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the retention box volume is limited to reduce space requirements, then the space requirement is reduced, but the ability to retain fluids without discharge is worsened

Engineering Contradiction:

Improveretention box volumeVSAvoidfluid retention reliability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The drainage system uses the aircraft's own motion (dynamic pressure) to activate drainage automatically when in flight, without requiring external control systems. The stub self-regulates based on flight conditions, opening when dynamic pressure exceeds the threshold and closing when it drops below, ensuring reliable fluid discharge only during appropriate flight phases.

Inventive Principle:

Principle #25Self-service

2Reliability

If engine computer control or pressure measurement systems are used to control drainage, then drainage control reliability is improved, but device complexity is increased

Engineering Contradiction:

Improvedrainage control reliabilityVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The drainage stub functions autonomously by directly utilizing the dynamic pressure from aircraft motion to operate the closure member. The system requires no engine computer intervention, no pressure sensors, and no complex control electronics. The physical dynamic pressure difference between flight and ground conditions directly actuates the drainage mechanism, achieving reliable control with minimal complexity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention replaces complex electronic control systems (engine computer, pressure sensors, electrical actuators) with a simple mechanical system that directly converts dynamic pressure into mechanical motion of the closure member. This mechanical substitution eliminates the need for complex control systems while maintaining reliable drainage control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the stub discharges fluids autonomously based on dynamic pressure, then fluid discharge reliability during flight is improved, but the risk of fluid discharge on ground is increased

Engineering Contradiction:

Improvefluid discharge reliabilityVSAvoidfluid leakage risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system exploits the change in dynamic pressure parameter between ground and flight conditions. On the ground, dynamic pressure is near zero, keeping the closure member closed. During flight, dynamic pressure increases above the threshold, automatically opening the closure member for discharge. This parameter-based control ensures discharge occurs only under appropriate flight conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts the potentially harmful effect of dynamic pressure (which could cause unintended discharge) into a beneficial control mechanism. The same dynamic pressure that represents aircraft motion is used as the activating signal for safe discharge, ensuring fluids are only discharged when the aircraft is already in flight and motion is expected.

Inventive Principle:

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

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

Ensures safe and efficient drainage of fluids during flight by utilizing the aircraft's velocity-induced dynamic pressure, reducing the risk of fluid loss on the ground and eliminating the need for engine computer intervention or pressure measurements.

Implementation Method 1

the invention makes it possible to use a pressure difference such as the external dynamic pressure and therefore the velocity of the aircraft to trigger the drainage of the retention stub

Methodology Applied

Scientific EffectDynamic pressure: Pressure Gradient

Implementation Method 2

The more the velocity of the aircraft increases, the more the dynamic pressure increases. The stub is designed so that its drainage is actuated when the dynamic pressure has reached a certain threshold

Methodology Applied

Scientific EffectDynamic pressure force: Pressure Gradient

Data Source

PatentUS10017238B2Drained fluid evacuation stub for a propulsion assembly

Publication Date: 2018.07.10 SAFRAN AIRCRAFT ENGINES SAS

AI summary

Stub for discharging drained fluids for a propulsion unit. The stub includes a cavity for storing the drained fluids and at least one orifice for discharging the fluids contained in the storage cavity, and elements for measuring a difference in pressure outside the stub and a member for draining the storage cavity. The member is able to move between a first position of closing the discharge orifice and a second position of releasing the orifice, and is configured so as to move from the first to the second position when the difference in pressure is greater than, or equal to, a predetermined value.