Jet Engine Cleaning via Low-Velocity Solid Medium

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Solution Overview

Problem

Aircraft jet engines face efficiency reduction due to contamination from insects, dust, salt spray, and combustion residues, which existing cleaning methods like hot water or coal dust either fail to effectively remove or leave residues behind.

Innovation Solution

A method using thermolabile solids such as solid carbon dioxide and ice, introduced into the engine with a dispensing device that releases the cleaning medium at a low exit speed of 80 m/s or less, allowing the solids to be carried by the air flow through the engine for thorough cleaning without excessive kinetic energy loss or residue formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If cleaning medium is introduced at high velocity to improve cleaning effectiveness, then cleaning power increases, but surface damage and residue formation increase

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidsurface damage and residue

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the velocity parameter of the cleaning medium from high to low (80 m/s or less), transforming the cleaning mechanism from kinetic impact-dominated to airflow-convection-dominated. This parameter change resolves the contradiction by maintaining cleaning effectiveness through prolonged contact time and airflow transport while eliminating excessive kinetic energy that causes surface damage and residue.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes airflow (pneumatic system) to transport the cleaning medium through the engine rather than relying on high-velocity injection. The airflow carries the cleaning medium along the engine components, providing continuous contact and effective cleaning without the harmful high-impact effects of high-velocity projection.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Manufacturing precision

If thermolabile solids are used as cleaning medium to reduce residue, then cleaning purity improves, but kinetic energy loss increases

Engineering Contradiction:

Improvecleaning purityVSAvoidkinetic energy loss

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent employs airflow to compensate for the reduced kinetic energy of thermolabile solids. The gas stream carries the cleaning medium through the engine, maintaining sufficient energy for effective cleaning while the solids sublimates or melts without causing damage, achieving high cleaning purity with acceptable energy utilization.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent utilizes phase transition (sublimation or melting) of thermolabile solids like solid carbon dioxide or ice as the cleaning mechanism. These solids transition from solid to gas or liquid phase within the engine, providing cleaning action through phase change rather than kinetic impact, thereby achieving high purity cleaning with minimal kinetic energy requirements.

Inventive Principle:

Principle #36Phase transitions

3Strength

If cleaning medium is released at low velocity to reduce surface damage, then surface integrity improves, but cleaning reach to rear stages decreases

Engineering Contradiction:

Improvesurface integrityVSAvoidcleaning reach

Core Design Contradiction:

StrengthVSLength of moving object

Solution Approach 1:

The patent uses airflow as a transport medium to extend the cleaning reach. The gas stream carries the cleaning medium from the inlet through the entire engine length, including rear compressor stages, without relying on the initial velocity of the cleaning medium. This resolves the contradiction by decoupling cleaning reach from injection velocity.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The airflow is generated beforehand to create a transporting stream that carries the cleaning medium through the engine. This preliminary action of establishing airflow ensures that even low-velocity cleaning medium can reach all engine sections, as the airflow itself provides the necessary transport capability.

Inventive Principle:

Principle #10Preliminary 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 approach ensures effective cleaning of the compressor stages across the entire engine length, including rear stages, with minimal surface damage and residue introduction, maintaining engine efficiency and reducing fuel consumption.

Implementation Method 1

is conveyed through the engine by this airflow

Methodology Applied

Scientific EffectAir flow convection: Convection

Implementation Method 2

thermolabile solids such as solid carbon dioxide and ice

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentEP4197659A1Method and device for cleaning a jet engine

Publication Date: 2023.06.21 LUFTHANSA TECHNIK AG

Figure 1~2

AI summary

Method and apparatus for cleaning a jet engine with a cleaning medium containing solids, which are introduced into the engine by means of at least one discharge device (11). It is provided that the cleaning medium exits the discharge device (11) at an exit velocity of 80 m/s or less.