Nacelle Fluid Drain Labyrinth Gutter Aft Siphon

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Solution Overview

Problem

The elimination of the lower bifurcation in new aircraft engine nacelle designs necessitates a new fluid drainage system to effectively remove flammable fluids from the core compartment without compromising aerodynamics or fire safety.

Innovation Solution

The aircraft engine nacelle incorporates a labyrinth gutter with a drain fin and a siphon system, where the gutter is configured to drain fluids aft through the inner fixed structure, and the siphon utilizes air pressure differentials to assist fluid removal, ensuring gravitational drainage and fire safety by preventing ignition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the lower bifurcation is eliminated to simplify nacelle structure, then device complexity is reduced, but fluid drainage capability deteriorates

Engineering Contradiction:

Improvenacelle structureVSAvoidfluid drainage

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The fluid drainage system is segmented into multiple functional components: a gutter for collecting fluids, a siphon tube for transporting fluids, and a drain fin for directing fluids outward. This segmentation allows the drainage function to be maintained without requiring the lower bifurcation structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The siphon tube acts as an intermediary mechanism that transfers fluids from the core compartment through the inner fixed structure to the exterior. It mediates the fluid drainage process by utilizing air pressure differentials and gravitational forces, enabling effective drainage without the lower bifurcation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If a traditional fluid drain system is used without lower bifurcation, then aerodynamic performance is improved, but fire safety deteriorates

Engineering Contradiction:

Improveaerodynamic performanceVSAvoidfire risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The labyrinth gutter design converts the potentially harmful accumulation of flammable fluids into a beneficial drainage pathway. The labyrinth structure forces fluids to travel a extended path with multiple directional changes, ensuring complete drainage while the drain fin directs the flow away from the core compartment, thereby reducing fire risk.

Inventive Principle:

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

Solution Approach 2:

The siphon tube utilizes pneumatic principles by creating air pressure differentials to drive fluid movement. The siphon effect, combined with gravitational forces, enables reliable fluid transport through the inner fixed structure, ensuring that fluids are continuously removed from the core compartment to minimize fire hazards.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Use of energy by stationary object

If gravitational drainage is used, then energy consumption is reduced, but drainage efficiency deteriorates

Engineering Contradiction:

Improveenergy consumptionVSAvoiddrainage efficiency

Core Design Contradiction:

Use of energy by stationary objectVSProductivity

Solution Approach 1:

The system merges multiple drainage mechanisms: gravitational drainage for passive fluid movement, siphon action for active fluid transport, and air pressure differentials for enhanced flow. This combination achieves high drainage efficiency while minimizing energy consumption by utilizing natural forces wherever possible.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The drainage system operates continuously through periodic siphon cycles, where air pressure differentials are repeatedly established to move fluids through the siphon tube. This periodic action ensures consistent drainage efficiency without requiring continuous external energy input.

Inventive Principle:

Principle #19Periodic action

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 solution enables efficient and safe drainage of fluids from the core compartment, reducing the risk of fire by utilizing a labyrinth design that prevents ignition and leveraging air pressure to facilitate fluid movement, even in designs without a lower bifurcation.

Implementation Method 1

The gutter may comprise a labyrinth structure

Methodology Applied

Scientific EffectLabyrinth structure:

Implementation Method 2

The siphon may comprise a tube configured to transfer air from a bypass duct to an exit of the gutter

Methodology Applied

Scientific EffectAir pressure differential: Pressure Gradient

Implementation Method 3

A siphon located in the inner fixed structure and comprising an orifice in an outer surface of the inner fixed structure

Methodology Applied

Scientific EffectSiphon effect: Syphon

Implementation Method 4

the gutter is configured to drain fluids in an aft direction through the inner fixed structure

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS10167741B2Nacelle fluid drain

Publication Date: 2019.01.01 ROHR INC

AI summary

An aircraft nacelle may comprise an inner fixed structure and an outer sleeve. The aircraft nacelle may comprise an O-duct thrust reverser. A drain gutter may be located in the inner fixed structure. The drain gutter may comprise a labyrinth configuration. The drain gutter may drain fluids in an aft direction through the inner fixed structure. The fluids may exit through a drain fin located at a station plane aft of the outer sleeve.