Gas Turbine Compressor Control During Acceleration
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Solution Overview
Problem
Conventional gas turbine engine compressors face issues during acceleration, where the low-pressure compressor operates at a low pressure ratio due to slow rotation and high pressure ratio across the high-pressure compressor, leading to restricted mass flow and reduced engine power, potentially causing 'overshoot' and damage.
Innovation Solution
A controller is configured to control the low-pressure compressor's variable geometry actuator based on both low-pressure compressor speed and high-pressure compressor parameters, switching between schedules to adjust inlet guide vane angles and bleed valve positions, ensuring optimal operation and preventing excessive high-pressure compressor rotational speed increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the low-pressure compressor operates at high rotational speed, then the compressor pressure ratio increases, but the high-pressure compressor rotational speed increases excessively causing runaway and potential damage
Solution Approach 1:
The controller continuously monitors the high-pressure compressor rotational speed and adjusts the low-pressure compressor variable geometry actuator accordingly. When the high-pressure compressor speed exceeds a threshold, the controller modifies the low-pressure compressor's inlet guide vane angle or bleed valve position to reduce its pressure ratio, thereby preventing excessive speed increase in the high-pressure compressor.
Solution Approach 2:
The system dynamically changes the operational parameters of the low-pressure compressor (inlet guide vane angle, bleed valve position) based on the high-pressure compressor speed conditions. By adjusting these geometric parameters, the low-pressure compressor's pressure ratio is modified to control the mass flow and prevent runaway conditions in the high-pressure compressor.
2Speed
If the low-pressure compressor operates at low pressure ratio, then the high-pressure compressor speed is controlled, but the engine power is reduced
Solution Approach 1:
The system dynamically adjusts the low-pressure compressor's variable geometry actuator during acceleration transients to temporarily reduce pressure ratio and control high-pressure compressor speed. Once the transient condition passes, the system returns to optimal pressure ratio settings to maximize engine power, achieving both speed control and power maintenance through time-varying control.
3Device complexity
If conventional single-schedule control is used, then the control system is simple, but it cannot prevent overshoot and damage during acceleration
Solution Approach 1:
The controller implements feedback control by monitoring high-pressure compressor rotational speed and adjusting the low-pressure compressor variable geometry actuator in real-time. This closed-loop control prevents overshoot and potential damage during acceleration without requiring complex multi-schedule control tables, maintaining simplicity while improving reliability.
Data Source
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AI summary
A gas turbine engine compressor operating system for a gas turbine engine (10) is disclosed. The gas turbine engine (10) comprises a low pressure compressor (14) and a high pressure compressor (15). The low and high pressure compressors (14, 15) are driven by low and high pressure shafts (26, 27) respectively, with the high pressure compressor (15) being provided downstream in core mass flow of the low pressure compressor (14). The compressor operating system comprises a controller (42) configured to control a variable geometry actuator (32, 34) of the low pressure compressor (14). The controller (42) is configured to control the variable geometry actuator (32, 34) on the basis of low pressure compressor (14) rotational speed (N1) and a high pressure compressor operating parameter such as one or more of core mass flow rate (m), high pressure compressor pressure ratio (P30:P26), high pressure compressor rotational speed (N2), and high pressure compressor variable guide vane angle (α).