Gas Turbine Bleed-Off Valve Control for Engine Recovery
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Solution Overview
Problem
Existing techniques for gas turbine engine recovery from disturbances such as engine surge or flame-out are inadequate, often leading to cyclical instabilities and incomplete stabilization due to premature closure of bleed-off valves.
Innovation Solution
A method and system for controlling bleed-off valves in gas turbine engines, where the valve is maintained at least partially open upon detection of an unintended disturbance, with closure controlled based on rotor acceleration thresholds to ensure stable recovery, using a processing unit and computer-readable medium to execute the control logic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bleed-off valve is closed early to restore engine operation, then the engine can return to normal operation faster, but the engine may enter cyclical instabilities and fail to fully recover
Solution Approach 1:
The control system continuously monitors rotor acceleration and uses this feedback to dynamically adjust bleed-off valve closure timing. The valve closure is triggered only when rotor acceleration reaches a threshold and is maintained for a specified duration, ensuring the engine has sufficiently recovered before valve closure, thus preventing cyclical instabilities while enabling timely recovery.
Solution Approach 2:
The system transitions from static valve closure timing to dynamic timing based on real-time rotor acceleration conditions. The closure timing adapts to the actual engine recovery state, allowing optimal balance between recovery speed and stabilization reliability under varying operating conditions.
2Reliability
If the bleed-off valve remains open longer to ensure stable recovery, then engine stabilization is improved, but the recovery time increases
Solution Approach 1:
The system uses real-time rotor acceleration feedback to determine the precise moment when stable recovery has been achieved. This allows the bleed-off valve to remain open only as long as necessary for stabilization, then closes promptly to minimize recovery time loss.
Solution Approach 2:
The system changes the operational parameter of valve timing based on rotor acceleration thresholds. By monitoring when acceleration reaches and sustains a threshold value, the system optimizes the balance between maintaining stability and minimizing time loss.
3Ease of operation
If existing techniques are used for valve control, then the system is simple to operate, but the engine cannot fully recover from disturbances
Solution Approach 1:
The control system automatically monitors engine parameters and autonomously determines the optimal valve closure timing based on rotor acceleration. This self-service approach eliminates the need for complex manual control while achieving complete engine recovery, maintaining ease of operation through automated decision-making.
Solution Approach 2:
The system uses automated feedback from rotor acceleration sensors to control valve timing, replacing simple but ineffective manual or fixed-timing control. This feedback mechanism enables complete recovery without increasing operational complexity for the user.
Data Source
AI summary
Methods and systems for controlling a bleed-off valve of a gas turbine engine are described. The method comprises maintaining a first bleed-off valve associated with a first compressor of the gas turbine engine at least partially open upon detection of an unintended engine disturbance causing a drop in pressure of a combustion chamber of the engine; monitoring a rotor acceleration of the first compressor; and controlling closure of the first bleed-off valve when the rotor acceleration of the first compressor reaches a first threshold for a first duration.