Variable Guide Vane Assembly Control for Inlet Flow Distortion
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Solution Overview
Problem
Existing variable guide vane control systems in aircraft engines do not effectively account for inlet flow distortion, leading to non-optimized performance of downstream rotors due to the influence of swirl angles, which affects compressor stability and efficiency.
Innovation Solution
A control system that predicts and adjusts the exit flow angle by considering geometric angles and operating parameters, including flight and engine conditions, to modulate variable guide vanes until the predicted exit flow angle matches a target angle, thereby optimizing the incidence angle for improved rotor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional variable guide vane control systems are used, then the system structure is simple, but the compressor stability and efficiency deteriorate due to inlet flow distortion and swirl angles
Solution Approach 1:
The patent implements a feedback control system where a sensor measures the actual exit flow angle of the guide vanes, and a controller compares this measurement with the target exit flow angle to determine necessary adjustments. This closed-loop feedback mechanism corrects for inlet flow distortion and swirl angles, improving compressor stability while managing system complexity through automated control.
Solution Approach 2:
The patent replaces traditional mechanical linkage control systems with an electronic control system comprising sensors, controllers, and actuators. This substitution enables more precise control of the guide vane angle by using electronic signals rather than mechanical linkages, improving compressor stability while allowing for sophisticated control algorithms to manage the increased complexity.
2Productivity
If guide vanes are not modulated to compensate for flow distortion, then the device complexity is low, but the downstream rotor performance deteriorates due to non-optimized incidence angles
Solution Approach 1:
The feedback control system continuously monitors the exit flow angle and adjusts the guide vane position to optimize the incidence angle for downstream rotors. This ensures maximum rotor performance by dynamically compensating for flow distortion and swirl effects, while the automated feedback mechanism manages the complexity of the control system.
Solution Approach 2:
The control system predicts the required guide vane angle adjustment based on measured parameters and operating conditions before the flow distortion adversely affects rotor performance. This preliminary action optimizes the incidence angle in advance, improving rotor performance while managing control complexity through proactive adjustment.
3Loss of energy
If the exit flow angle is not predicted and adjusted, then the ease of operation is high, but the compressor efficiency deteriorates due to inlet flow distortion
Solution Approach 1:
The control system automatically predicts the exit flow angle based on measured parameters and operating conditions, and self-adjusts the guide vane position to optimize compressor efficiency. This self-service capability compensates for inlet flow distortion without requiring manual intervention, improving compressor efficiency while maintaining ease of operation through automation.
Solution Approach 2:
The feedback mechanism continuously monitors operating conditions and exit flow angle, automatically adjusting the guide vanes to minimize energy losses from flow distortion. This automated feedback control improves compressor efficiency by eliminating the need for manual operation while managing system complexity through intelligent control algorithms.
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4B
AI summary
A method of operating a variable guide vane assembly (40) of an aircraft engine (10), the variable guide vane assembly (40) including guide vanes (42) rotatable about respective spanwise axes (S1) and circumferentially distributed about a central axis (11), the method comprising: obtaining a target exit flow angle defined between a direction of a flow exiting the guide vanes (42) and the central axis (11); predicting an exit flow angle (T2; T2') as a function of at least a geometric angle (T1), the exit flow angle (T2; T2') defined between the direction of the flow (F1; F1') exiting the guide vanes (42) and the central axis (11), the geometric angle (T1) defined between the guide vanes (42) and the central axis (11); and when a difference between the exit flow angle (T2; T2') and the target exit flow angle is above a threshold, modulating the guide vanes (42) to modify the geometric angle (T1) until the difference between the exit flow angle (T2; T2') and the target exit flow angle is at or below the threshold.