Adaptive Fan Array Mitigates Gas Turbine Inlet Distortion
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Solution Overview
Problem
Gas turbine engines experience distortion due to pressure gradients and swirl, leading to engine stall and undesirable aeromechanical behavior, particularly in embedded applications with multiple inlets that result in differential air flows and pressures.
Innovation Solution
An inlet distortion mitigation system comprising multiple auxiliary inlet fans and a control unit that adjusts their rotation speed in response to pressure differentials, ensuring uniform air distribution to the primary fan, including configurations with contra-rotating fans and variable pitch blades, and an auxiliary fan array to mitigate distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple inlet ducts are used to supply air to the gas turbine engine, then the engine can operate in embedded applications with improved thrust, but pressure gradients and swirl cause distortion leading to engine stall and undesirable aeromechanical behavior
Solution Approach 1:
The inlet distortion mitigation system divides the airflow into multiple independent zones corresponding to different inlet ducts, with individual auxiliary fans controlling each zone. This segmentation allows independent adjustment of airflow from each duct, enabling precise control over pressure distribution and swirl mitigation at the primary fan face.
Solution Approach 2:
The system dynamically changes operational parameters by varying the rotation speed of auxiliary fans based on detected pressure differentials and swirl conditions. The control system adjusts fan speeds in real-time to optimize airflow parameters, maintaining uniform pressure distribution across the primary fan face while preventing distortion-related stall.
2Reliability
If auxiliary inlet fans are added to mitigate distortion, then flow distribution uniformity at the primary fan is improved, but device complexity increases
Solution Approach 1:
The auxiliary fans are designed to perform multiple functions: they can operate independently in each inlet duct for localized distortion mitigation, work in coordinated pairs for swirl reduction, and be controlled individually or collectively based on flight conditions. This multi-functionality reduces the need for separate systems for different mitigation strategies.
Solution Approach 2:
The system incorporates sensors that automatically detect pressure differentials and swirl conditions, with a control system that autonomously adjusts auxiliary fan speeds without pilot intervention. The fans self-regulate based on real-time feedback from pressure sensors, reducing the need for complex manual control mechanisms.
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
The system effectively mitigates distortions, preventing engine stall and improving aeromechanical performance by ensuring uniform air distribution and adapting to various flight maneuvers, enhancing the engine's robustness and maneuverability.
Implementation Method 1
the engine may experience high distortion in the form of pressure gradients and swirl
Implementation Method 2
The control unit may be configured to vary individually a rotation speed of each of the first electric inlet fan and the second electric inlet fan in response to a pressure differential in the flow path
Data Source
AI summary
An aircraft includes a duct system configured to receive a flow of air therethrough and a gas turbine engine. The duct system includes a main duct and inlet ducts arranged fluidly upstream of the main duct so as to conduct the flow of air from the inlet ducts into the main duct. The gas turbine engine in downstream fluid communication with the main duct.