Variable Inlet Vane Scheduling for Gas Turbine Foreign Object Deflection
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Solution Overview
Problem
Gas turbine engines face operational challenges due to inclement weather conditions such as hail, ice, and dirt, which can affect the low pressure compressor's efficiency and reliability, especially at altitudes between 10,000 to 25,000 feet and during idle power settings, where existing control systems are not responsive enough to protect the engine.
Innovation Solution
The implementation of a method and gas turbine engine design that includes a plurality of inlet vanes capable of moving between a non-diversion and diversion position, deflecting foreign objects through a downstream bleed, with the vanes moving about 15° to 50° in response to programmed flight conditions, using an actuator to adjust their position based on altitude and power settings to protect the engine from debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If variable inlet vanes are used to improve low pressure compressor operability, then compressor efficiency is improved, but the engine becomes more vulnerable to foreign object ingestion during specific flight conditions
Solution Approach 1:
The inlet vane system transitions from a static configuration optimized for compressor efficiency to a dynamic system that can change position based on flight conditions. The controller automatically adjusts vane angle according to altitude and power setting, enabling the system to switch between efficiency-optimized and protection-optimized configurations as needed
Solution Approach 2:
The system changes the operational parameters of the inlet vanes based on flight conditions. At high altitude idle conditions, the vanes are positioned at a larger angle (15-50 degrees) to deflect foreign objects, while at other conditions they are positioned at smaller angles to optimize compressor operability and efficiency
2Reliability
If inlet vanes are positioned to deflect foreign objects, then engine protection is improved, but compressor operability and efficiency deteriorate
Solution Approach 1:
The system dynamically adjusts vane position based on real-time flight conditions rather than maintaining a fixed protective position. This allows the compressor to operate at optimal efficiency during most flight conditions while providing protection only when and where it is needed
Solution Approach 2:
The vane angle parameter is changed based on flight condition parameters (altitude and power setting). During high altitude idle conditions, the angle increases to 15-50 degrees for protection; during other conditions, the angle decreases to optimize compressor operability and efficiency
3Device complexity
If a fixed vane position system is used, then device complexity is reduced, but the system cannot respond to changing weather and flight conditions
Solution Approach 1:
The system incorporates feedback from flight condition sensors (altitude and power setting) to the controller, which automatically adjusts vane position accordingly. This feedback loop enables the system to adapt to changing conditions without requiring complex manual intervention or overly sophisticated sensor systems
Solution Approach 2:
The system is self-regulating based on flight conditions. The controller automatically determines when protective positioning is needed and adjusts the vanes accordingly, eliminating the need for complex manual control systems or overly sophisticated external monitoring
Data Source
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AI summary
A method of protecting a gas turbine engine according an exemplary aspect of the present disclosure includes, among other things, the steps of determining at least one flight condition of an aircraft and comparing the at least one flight condition to a programmed condition. The method further includes the steps of moving a plurality of inlet vanes of a low pressure compressor from a first position to a second position if the step of comparing the at least one flight condition to the programmed flight condition determines the programmed flight condition are met and deflecting any foreign objects with the plurality of inlet vanes.