Bowed Rotor Motoring Control via Dynamic Speed Adjustment

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Solution Overview

Problem

Conventional bowed rotor motoring methods for gas turbine engines are inefficient and prolonged, risking engine damage due to thermal expansion-induced bowing, as they operate at constant speeds without real-time parameter monitoring.

Innovation Solution

A method and system that actively monitor and adjust the speed and time of motoring based on gap, speed, and vibration parameters using sensors and a controller to optimize motoring speed and duration, preventing blade rub and destructive vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gas turbine engine is motored at a constant speed for an extended period to cool down the rotor, then the bowed rotor condition is mitigated, but the motoring time is prolonged and engine damage risk increases

Engineering Contradiction:
Improvebowed rotor mitigation effectivenessVSAvoidmotoring time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies dynamics by transitioning from constant speed motoring to variable speed motoring. The controller dynamically adjusts the motoring speed based on real-time feedback from sensors monitoring gap parameters, speed parameters, and vibration parameters. This allows the system to optimize cooling effectiveness while reducing overall motoring time by operating at higher speeds when conditions permit.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback control by continuously monitoring engine parameters (gap between rotor and stator, rotational speed, vibration levels) and using this information to adjust the motoring speed. The controller receives sensor data and modifies the ATS operation accordingly, enabling adaptive speed adjustment that balances cooling effectiveness with time efficiency and safety.

Inventive Principle:
Principle #23Feedback

2Loss of time

If the motoring speed is increased to reduce cooling time, then the motoring duration is shortened, but the risk of blade rub and destructive vibrations increases

Engineering Contradiction:
Improvemotoring timeVSAvoidblade rub and vibration damage risk
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The feedback control system continuously monitors vibration parameters and gap measurements, allowing the controller to detect early signs of blade rub or excessive vibrations. When such conditions are detected, the system automatically reduces speed or terminates motoring, preventing damage while still allowing high-speed operation when safe.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts motoring speed based on real-time condition assessment. Rather than maintaining a fixed conservative speed limit, the system can operate at higher speeds when sensor data indicates safe conditions, and rapidly reduce speed when hazards are detected, optimizing the balance between time efficiency and safety.

Inventive Principle:
Principle #15Dynamics

3Productivity

If real-time parameter monitoring and dynamic speed adjustment systems are implemented, then motoring efficiency and safety are improved, but the device complexity increases

Engineering Contradiction:
Improvemotoring efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies universality by utilizing the existing ATS infrastructure and integrating sensor systems that may already be present in the engine for other monitoring purposes. The control system leverages available sensor data (gap measurements, vibration sensors, speed sensors) and repurposes them for bowed rotor motoring optimization, reducing the need for entirely new specialized components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Loss of time

If the gas turbine engine is motored at high speed for a short duration, then the motoring time is reduced, but the cooling effectiveness may be insufficient

Engineering Contradiction:
Improvemotoring timeVSAvoidrotor temperature reduction
Core Design Contradiction:
Loss of timeVSTemperature

Solution Approach 1:

The system employs periodic monitoring and adjustment of motoring parameters. Rather than a single continuous high-speed phase, the controller implements cycles of high-speed motoring interspersed with monitoring periods where sensor data is assessed and speed adjustments are made. This periodic action ensures adequate cooling while minimizing total time through optimized high-speed intervals.

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 approach reduces bowed rotor motoring time and prevents engine damage by dynamically adjusting motoring speed and duration based on real-time engine conditions, enhancing the efficiency and safety of the process.

Implementation Method 1

use the ATS to drive rotation (i.e., cool-down motoring) of a spool within the engine for an extended period of time at a selected speed

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 2

detecting a gap parameter of a gas turbine engine; detecting a speed parameter of the gas turbine engine; detecting a vibration parameter of the gas turbine engine

Methodology Applied
Scientific EffectGap measurement:

Implementation Method 3

motoring the gas turbine at a second speed in response to at least one gap parameter, speed parameter, and vibration parameter

Methodology Applied
Scientific EffectFeedback control: Feedback

Data Source

PatentEP3406864B1Bowed rotor motoring control
Publication Date: 2020.10.07 HAMILTON SUNDSTRAND CORP
  • EP3406864B1 patent drawingFigure 1
  • EP3406864B1 patent drawingFigure 2A~2B
  • EP3406864B1 patent drawingFigure 3~4A

AI summary

A method of motoring a gas turbine engine (250) is provided. The method comprises: determining a first speed to motor a gas turbine engine (250) for cooling; motoring a gas turbine engine (250) at the first speed; detecting a gap parameter of a gas turbine engine (250) ; detecting a speed parameter of the gas turbine engine (250) ; detecting a vibration parameter of the gas turbine engine (250); and motoring the gas turbine at a second speed in response to at least one gap parameter, speed parameter, and vibration parameter.