Aircraft Engine Compressor Flow Control for Surge Margin

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Solution Overview

Problem

Gas turbine engines experience undesirable high power engine surges due to compressor stalls, which can have significant consequences, and existing methods fail to effectively manage aerodynamic stability to prevent these events while optimizing engine performance.

Innovation Solution

A method and system for operating aircraft engines that determine a compressor mass flow limit based on actual operating parameters, comparing it to the actual compressor mass flow to govern engine operation and maintain aerodynamic stability by adjusting power or rotational speed to prevent surges, using a compressor map and real-time monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the engine operates at high power, then the engine power output increases, but the risk of compressor surge increases

Engineering Contradiction:
Improveengine powerVSAvoidaerodynamic stability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The control system proactively reduces engine power before a compressor surge actually occurs. By monitoring operating parameters and predicting surge conditions, the system takes preventive action by reducing power output, thereby avoiding the harmful surge event while still allowing high power operation under safe conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors engine operating parameters (such as compressor inlet pressure, temperature, and flow rate) and uses this feedback to adjust power output in real-time. When parameters indicate approaching surge conditions, the control system responds by reducing power, creating a closed-loop control that maintains aerodynamic stability while maximizing safe power output.

Inventive Principle:
Principle #23Feedback

2Reliability

If the compressor mass flow is increased to prevent surge, then the surge margin is maintained, but the engine power output is reduced

Engineering Contradiction:
Improvesurge marginVSAvoidengine power output
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The system dynamically adjusts the compressor mass flow limit based on real-time operating conditions rather than using a fixed conservative limit. By continuously updating the mass flow limit according to actual engine state (speed, temperature, pressure), the system maintains adequate surge margin while allowing maximum possible power output for each operating condition.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system changes the operating parameters (specifically the compressor mass flow limit) as a function of engine operating conditions. The mass flow limit is adjusted based on parameters such as engine speed, inlet temperature, and pressure ratio, allowing the system to maintain surge protection while optimizing power output for each specific operating point.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4105470B1Method and system for operating an engine to prevent high power engine surges
Publication Date: 2026.03.04 PRATT & WHITNEY CANADA CORP
  • EP4105470B1 patent drawingFigure 1
  • EP4105470B1 patent drawingFigure 2
  • EP4105470B1 patent drawingFigure 3A

AI summary

Methods and systems for operating an aircraft engine (100) having a compressor are described. The method comprises determining, based on actual operating parameters of the aircraft engine (100), a compressor mass flow limit for an aerodynamic stability of the aircraft engine (100); determining an actual compressor mass flow of the compressor of the aircraft engine (100), wherein the actual compressor mass flow is based on measured values of the aircraft engine (100); comparing the actual compressor mass flow to the compressor mass flow limit; and governing operation of the aircraft engine (100) to cause an alternative compressor mass flow when the actual compressor mass flow reaches or is anticipated to reach the compressor mass flow limit.