Variable Stator Vane Rigging with Offset Actuator Holes
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Solution Overview
Problem
Existing variable stator vane systems in gas turbine engines face challenges in accurately calibrating and adjusting the angle of incidence, leading to aerodynamic inefficiencies and flow separation at low operational speeds and pressures, particularly with high compressor pressure ratios.
Innovation Solution
The introduction of an actuator with offset rigging holes in the actuator body and ram, allowing for precise alignment and fixation of the actuator ram to the variable stator vanes, enabling adjustable connection and accurate setting of the angle of incidence, which can be adjusted during the rigging process to accommodate design changes and correct mal-schedule issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high compressor pressure ratios are used, then the compressor can achieve higher power output, but the inlet to exit area ratios of stator vanes result in aerodynamic inefficiency and flow separation at low operational speeds and pressures
Solution Approach 1:
The patent implements variable stator vanes that can dynamically change their angle of incidence during compressor operation. The vanes are connected to an actuator mechanism that adjusts their position based on operational conditions, allowing the compressor to maintain optimal aerodynamic efficiency across different speed and pressure ranges while achieving high power output
2Reliability
If variable stator vanes are implemented to correct angle of incidence, then aerodynamic stability is improved at low speeds, but the complexity of the vane adjustment mechanism increases
Solution Approach 1:
The actuator mechanism serves multiple functions: it adjusts the angle of incidence of variable stator vanes, provides calibration capability through adjustable connecting arrangements, and enables verification of vane positions. This multi-functionality reduces the need for separate calibration devices and simplifies the overall system while maintaining aerodynamic stability
3Ease of manufacture
If previous calibration arrangements for vane position and actuator position are used, then the system can be set up, but sufficient adjustment capability is not provided for setting the relationship between actuator position and vane position
Solution Approach 1:
The connecting arrangement between the actuator and variable stator vanes is designed to be adjustable rather than fixed. This allows the calibration position to be dynamically modified during setup and operation, providing sufficient adjustment capability to establish the correct relationship between actuator position and vane position while maintaining ease of manufacture
Solution Approach 2:
The patent enables calibration by allowing adjustment of parameters such as the connecting arrangement geometry and actuator positioning. This provides the necessary adaptability to set precise relationships between actuator and vane positions, overcoming the limitations of fixed calibration arrangements while keeping the manufacturing process straightforward
Data Source
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AI summary
A method and apparatus for rigging a variable stator vane arrangement (100) for a gas turbine engine (10) is provided. The arrangement provides at least two sets of rigging holes to an actuator (200), with the actuator extension during rigging being dependent on which of the sets of holes are aligned. This allows the actuator extension to be adjustable during rigging, thereby facilitating different relationships between actuator extension and variable vane angle in use.