Turbojet Duct Damage Detection via Pressure Deviation

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Solution Overview

Problem

Current methods in turbojet engines fail to detect pipe degradation, leading to incidents such as slower acceleration, loss of thrust, or engine shutdown, as they only address sensor malfunctions and not faults within the pipe, which can cause pressure measurement errors.

Innovation Solution

A method involving simultaneous measurement of air pressure at two sensors, calculation of theoretical pressure, and comparison with thresholds to detect deviations, followed by a final test to indicate pipe degradation, which can then be confirmed through visual inspection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant pressure sensors are used to detect sensor malfunctions, then measurement reliability is improved, but pipe degradation cannot be detected

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidpipe degradation detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The invention segments the fault detection problem into two distinct parts: sensor malfunction detection (using redundant sensors) and pipe degradation detection (using the deviation test method). By separating these detection functions, the system can address each type of fault with appropriate methods without interference between them.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an intermediary element - the theoretical pressure model - that mediates between the actual pressure measurements and the fault detection process. By comparing actual readings against this theoretical model, the system can detect pipe degradation effects that would otherwise be indistinguishable from normal pressure variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If visual inspection is used to detect pipe defects, then pipe degradation can be detected, but it requires manual intervention and cannot provide early warning

Engineering Contradiction:
Improvepipe defect detection capabilityVSAvoidresponse time
Core Design Contradiction:
Difficulty of detecting and measuringVSLoss of time

Solution Approach 1:

The invention performs preliminary detection actions continuously through automated pressure monitoring and deviation testing. By constantly comparing actual pressure readings against theoretical values, the system detects pipe degradation early in its development, well before visual inspection would be necessary or possible.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback through automated monitoring that compares pressure measurements against theoretical models. This feedback loop provides real-time detection of deviations indicating pipe degradation, eliminating the time delay inherent in manual visual inspection schedules.

Inventive Principle:
Principle #23Feedback

3Reliability

If the system monitors pressure continuously, then early detection is possible, but false alarms may increase due to normal pressure variations

Engineering Contradiction:
Improveearly detection capabilityVSAvoidsignal-to-noise ratio
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The invention changes the monitoring parameter from absolute pressure values to pressure deviations from theoretical predictions. By monitoring the difference between actual and expected pressure rather than raw pressure values, the system filters out normal pressure variations and focuses on anomalies indicating pipe degradation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system applies a threshold-based approach that triggers alerts only when deviations exceed significant margins. This partial action strategy avoids reacting to every minor fluctuation while still detecting meaningful degradation patterns, balancing sensitivity with false alarm reduction.

Inventive Principle:
Principle #16Partial or excessive 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 method provides a reliable indication of pipe degradation, enabling early detection and potential prevention of engine incidents by triggering an alarm after successive positive tests, thus ensuring safer engine operation.

Implementation Method 1

a pressure unit which measures and converts the pressure of the air routed via a pressure sensor CP

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP3155232B1Method for assisting with the detection of damage to a turbojet duct
Publication Date: 2018.12.12 SAFRAN AIRCRAFT ENGINES SAS
  • EP3155232B1 patent drawingFigure 1~2

AI summary

The invention relates to a method (METH) for assisting with the detection of damage to a duct (CNL), said duct (CNL) being designed such as to convey a pressurised air flow collected at the outlet (S) of a high-pressure compressor (CMP) of a turbine engine (TB) to a first pressure sensor (CP1) and a second pressure sensor (CP2) of a computer (CT), the method (METH) comprising the following steps: (A) measuring a first air pressure (P1) at the first pressure sensor (CP1); (B) measuring a second air pressure (P2) at the second pressure sensor (CP2); (C) determining a theoretical pressure (Pth) of the air flow at the outlet (S) of the high-pressure compressor (CMP); (D) performing a first test (T1) regarding the difference between the first value (V1) and the theoretical pressure (Pth); (E) performing a second test (T2) regarding the difference between the second value (V2) and the theoretical pressure (Pth); and performing a final test (Tf), which is positive if the first difference test (T1) and the second difference test (T2) are positive, and negative otherwise.