Variable Stator Vane Control for Gas Turbine Compressor Tip Clearance
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Solution Overview
Problem
Existing compressor tip clearance management systems in high-pressure compressors fail to effectively adjust tip clearance to prevent blade rub conditions and efficiency losses due to limitations in controlling rotor speed and vane positioning.
Innovation Solution
A system and method that utilize variable stator vanes controlled by a controller to adjust the high-pressure compressor rotor speed, closing vanes to increase clearance when tip clearance is low and opening vanes to decrease clearance when it is high, based on predictive and sensed conditions, to maintain an optimal clearance range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If variable guide vanes are adjusted to optimize low pressure compressor characteristics, then low pressure compressor operating line and stall margin are improved, but high pressure compressor tip clearance cannot be controlled
Solution Approach 1:
The compressor is divided into two independent control zones: variable guide vanes control low pressure compressor characteristics while variable stator vanes control high pressure compressor tip clearance. This segmentation allows each section to be optimized independently without interfering with the other.
Solution Approach 2:
Variable stator vanes are introduced as an intermediary mechanism between the high pressure compressor rotor and the casing. By adjusting the angle of these intermediate vanes, the rotor speed is modified, which in turn controls the tip clearance of the high pressure compressor blades.
2Length of moving object
If high pressure compressor rotor speed is increased to decrease tip clearance, then clearance is reduced, but blade rub condition may occur
Solution Approach 1:
The control system continuously monitors tip clearance conditions and adjusts the variable stator vane position accordingly. When clearance approaches minimum safe limits, the system provides feedback to reduce rotor speed, preventing blade rub while maintaining optimal clearance.
Solution Approach 2:
The system dynamically adjusts rotor speed through variable stator vane positioning to maintain tip clearance within a safe operating range. This dynamic control allows the system to adapt to changing operating conditions and prevent both excessive clearance and blade rub conditions.
3Adaptability or versatility
If variable stator vanes are used to control high pressure compressor rotor speed, then tip clearance can be adjusted, but device complexity increases
Solution Approach 1:
The variable stator vanes serve multiple functions: they control high pressure compressor tip clearance, influence rotor speed, and can be integrated with existing engine control systems. This multi-functionality reduces the need for separate dedicated clearance control mechanisms.
Solution Approach 2:
The tip clearance control function is merged with the existing variable stator vane system. By combining clearance control with the existing vane architecture and control electronics, the system achieves enhanced functionality without proportionally increasing overall device complexity.
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
Effectively prevents blade rub conditions and improves efficiency by dynamically adjusting tip clearance, ensuring the high-pressure compressor operates within a predetermined range, thereby enhancing the overall performance and reliability of the gas turbine engine.
Implementation Method 1
The adjusting step includes closing the variable stator vanes, thereby decreasing the high pressure compressor rotor speed
Data Source
Figure 1
Figure 2~3
AI summary
A compressor tip clearance management system includes a compressor section having a low pressure compressor and a high pressure compressor arranged downstream from the low pressure compressor. A variable stator vane is arranged upstream from the high pressure compressor. The variable stator vane is connected to an actuator, and a controller is in communication with the actuator. The controller is configured to provide a command to the actuator to move the variable stator vane in response to a high pressure compressor clearance condition. A high pressure compressor rotor speed is altered, and the high pressure compressor clearance condition is changed to a desired clearance.