Jet Engine Nozzle Assembly for Solid Particle Cleaning

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Solution Overview

Problem

Aircraft jet engines face contamination issues due to insects, dust, salt mist, and combustion residues, which reduce efficiency and increase fuel consumption, and existing cleaning methods like hot water or coal dust are either ineffective or leave residues.

Innovation Solution

A nozzle device introducing a cleaning medium containing thermolabile solids like solid carbon dioxide or ice, carried by compressed air, effectively cleans the compressor stages by ensuring the solids are conveyed to the rear stages without premature contact with engine walls, using a carrier gas and precise nozzle placement to optimize cleaning efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hot water is used as cleaning medium, then cleaning effectiveness is improved, but water residues remain inside the engine

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidwater residues
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the physical state parameter of the cleaning medium from liquid (hot water) to solid (thermolabile solids like dry ice or ice particles). This parameter change allows the cleaning medium to be conveyed as solids that can be removed without leaving liquid residues, while still providing effective cleaning through the solids' kinetic energy and phase change effects.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If coal dust is used as cleaning medium, then abrasive cleaning action is improved, but surface damage and residues occur

Engineering Contradiction:
Improvecleaning actionVSAvoidsurface damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material composition parameter of the cleaning medium from hard abrasive particles (coal dust) to thermolabile solids (dry ice or ice particles). This parameter change provides cleaning effectiveness through the solids' sublimation or melting effects and kinetic energy, while avoiding the surface damage caused by hard abrasives.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses thermolabile solids that are consumed during the cleaning process through sublimation or melting. These short-living cleaning particles provide their cleaning effect and then disappear, leaving no persistent residues or damaging deposits on engine surfaces, unlike durable abrasive materials.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If solids are introduced with high kinetic energy, then cleaning effectiveness is improved, but solids collide with compressor walls prematurely

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidsolids collision with walls
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent employs dynamic control of the carrier gas flow to convey solids through the compressor stages. The solids are introduced with controlled kinetic energy that allows them to follow the gas flow path and reach the desired cleaning zones without premature wall collisions, adapting to the flow dynamics within the engine.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses carrier gas as an intermediary medium to transport the thermolabile solids through the compressor stages. The carrier gas protects the solids from direct contact with compressor walls by maintaining them in suspension and guiding them along the flow path, while still allowing the solids to contact and clean the blade surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The method achieves thorough and uniform cleaning of all compressor stages, reducing contamination and maintaining thermodynamic efficiency while minimizing water introduction and avoiding residue issues.

Implementation Method 1

the solids are carried along by the gas flow in the engine and thus also conveyed to the rearmost compressor stages

Methodology Applied
Scientific EffectEntrainment: Entrainment

Implementation Method 2

thermolabile solids such as carbon dioxide or ice (water ice) are preferred

Methodology Applied
Scientific EffectSublimation: Sublimation

Implementation Method 3

ensure that thermolabile solids, such as carbon dioxide or ice, do not release all their kinetic energy and/or sublimate or melt in the front stages of the compressor

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP3189934B1Device for cleaning a jet engine
Publication Date: 2021.04.07 LUFTHANSA TECHNIK AG
  • EP3189934B1 patent drawingFigure 1~2
  • EP3189934B1 patent drawingFigure 3

AI summary

The invention relates to a nozzle assembly with at least one nozzle (107) designed for introducing a cleaning medium containing solids into a jet engine, which has means for a rotationally fixed connection to the shaft of the turbofan of a jet engine, and which has a rotary coupling (105) to which a line connection can be attached. According to the invention, the lines (108) for guiding the cleaning medium from the rotary coupling (105) to the nozzles (107) are designed such that a solid can follow the flow unhindered and does not condense on the pipe walls or sublimate. A further aspect of the invention is a correspondingly designed arrangement comprising such a nozzle assembly and an engine.