Stub-Tandem Variable Inlet Guide Vanes for Swirl Control
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Solution Overview
Problem
Gas turbine engines experience nonsynchronous vibration and flow instability due to aerodynamic mismatch effects, particularly in high-pressure-ratio multistage compressors, which can lead to blade damage and reduced performance.
Innovation Solution
The implementation of stub-tandem variable inlet guide vanes, comprising a full-span and part-span vane configuration, provides two degrees of freedom to control swirl distribution, adjusting pitch to reduce tip incidence and nonsynchronous vibration in compressor rotor blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-pressure-ratio multistage compressors are used to improve engine performance, then power output increases, but nonsynchronous vibration and flow instability occur due to aerodynamic mismatch effects
Solution Approach 1:
The inlet guide vane assembly is segmented into multiple independently controllable rows of vanes rather than a single unified structure. Each row can be adjusted to different angles, allowing differential control of airflow at various radial positions. This segmentation enables optimization of airflow distribution to prevent aerodynamic mismatch and nonsynchronous vibration while maintaining high-pressure-ratio compression.
Solution Approach 2:
The inlet guide vanes are made dynamically adjustable during engine operation through actuation systems that change vane angles based on operating conditions. This dynamic capability allows the compressor to maintain optimal airflow patterns across varying power settings, preventing flow instability and nonsynchronous vibration that would occur with fixed-geometry designs at high pressure ratios.
2Stability of the object's composition
If variable inlet guide vanes are implemented to control swirl distribution, then nonsynchronous vibration is reduced, but device complexity increases
Solution Approach 1:
The vane assembly is divided into multiple rows that can be independently controlled, allowing targeted adjustment of swirl distribution at different radial positions. This segmentation enables effective reduction of nonsynchronous vibration by addressing specific flow mismatch issues without requiring complex control of every individual vane, thereby managing overall system complexity.
Solution Approach 2:
The variable inlet guide vane system serves multiple functions: it controls overall swirl distribution, adjusts airflow angles for different operating conditions, and specifically targets nonsynchronous vibration reduction. This multi-functionality consolidates several control needs into a single integrated system, reducing the need for additional separate devices and managing complexity.
Data Source
AI summary
Gas turbine engine including stub-tandem variable inlet guide vanes are disclosed. An example gas turbine engine includes a compressor, a variable inlet guide vane upstream of the compressor, and a part-span vane positioned between at least a portion of the variable inlet guide vane and the compressor in an axial direction defined by the gas turbine engine.