Dynamic Engine Motoring for Rotor Bow Mitigation
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Solution Overview
Problem
Gas turbine engines experience rotor bowing due to thermal gradients after shutdown, leading to potential damage and extended downtime as the engine components cool unevenly, making it unsafe to restart until the bow dissipates to an acceptable level.
Innovation Solution
A dynamic motoring method and system that initiates engine rotation for an initial duration and interval, measuring real-time engine parameters like temperature to adjust the motoring duration and interval dynamically, controlling the engine speed to mitigate rotor bowing by ensuring uniform cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine is shut down for cooling, then the thermal gradient and rotor bowing are reduced, but the engine downtime and productivity are increased
Solution Approach 1:
The system performs motoring action before engine restart to pre-mitigate rotor bowing. By rotating the engine at controlled speeds and durations prior to startup, the system reduces thermal gradients and rotor distortion in advance, allowing shorter cooling wait times and faster turnaround between operations.
Solution Approach 2:
Instead of idle cooling wait time, the system continuously performs useful motoring actions during the cooling period. The engine is motor ed at intervals to maintain rotational motion that distributes thermal energy and prevents severe bowing, transforming unproductive cooling time into productive rotor conditioning.
2Device complexity
If fixed motoring duration and interval are used, then the control system is simple, but the rotor bow mitigation efficiency is insufficient
Solution Approach 1:
The motoring system transitions from fixed static parameters to dynamic adjustable parameters. The control system modifies motoring duration and interval based on real-time engine temperature measurements and operational conditions, optimizing rotor bow mitigation efficiency while adapting to varying thermal states without requiring overly complex control architecture.
Solution Approach 2:
The system changes operational parameters (motoring duration and interval) based on measured engine conditions. By adjusting these parameters dynamically according to temperature readings and thermal gradient assessments, the system achieves superior rotor bow mitigation compared to fixed parameters, while maintaining reasonable control system complexity through rule-based adaptation.
3Reliability
If real-time parameter measurement and dynamic adjustment are implemented, then the rotor bow mitigation is improved, but the measurement and control complexity increases
Solution Approach 1:
The system implements feedback loops where engine temperature and operational parameters are continuously measured and fed back to the control system. This feedback enables real-time adjustment of motoring duration and interval to optimize rotor bow mitigation, achieving high reliability through adaptive control while managing complexity through systematic feedback processing.
Solution Approach 2:
The control system automatically adjusts motoring parameters based on measured engine conditions without requiring external intervention. The system self-regulates by monitoring its own operational state and making necessary adjustments to motoring duration and interval, reducing the need for complex external control infrastructure while maintaining high mitigation effectiveness.
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 the lock-out time by dynamically managing the engine's motoring duration and interval based on real-time temperature measurements, thereby minimizing rotor distortion and enabling safer, quicker engine restarts.
Implementation Method 1
measuring at least one engine parameter in real-time during the motoring, the at least one engine parameter comprising a temperature of the engine
Implementation Method 2
As the temperature of the engine decreases towards ambient temperature, a thermal gradient develops in the engine leading to the upper portion of the engine cooling more slowly than the lower portion. This results in distortion (or bowing) of the engine components due to thermal expansion (or contraction).
Implementation Method 3
A dynamic motoring method and system that initiates engine rotation for an initial duration and interval, measuring real-time engine parameters like temperature to adjust the motoring duration and interval dynamically, controlling the engine speed to mitigate rotor bowing by ensuring uniform cooling.
Data Source
AI summary
There is provided a dynamic motoring system and method for an aircraft engine. Motoring of the engine is initiated for an initial motoring duration and at an initial motoring interval. At least one engine parameter is measured in real-time during the motoring, the at least one engine parameter comprising a temperature of the engine. The initial motoring duration and the initial motoring interval are modified in real-time, based on a value of the at least one engine parameter during the motoring, to obtain a modified motoring duration and a modified motoring interval. The motoring continues for the modified motoring duration and at the modified motoring interval, with a speed of rotation of the engine being controlled using the modified motoring interval.