Fan System Passive Leading Edge Slats
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Solution Overview
Problem
Existing fan systems for gas turbine engines face challenges in achieving high propulsive efficiency with minimal drag and weight, particularly in redistributing airflow and weight effectively across various geometries and applications.
Innovation Solution
A fan system with rotatable blades attached to a ring airfoil, featuring cambered cross sections and contra-rotationally disposed rotors with leading edge slats made of Ti-6Al-4V alloy, which close under load to optimize airflow and reduce weight, while maintaining thrust generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fan blade systems employ various geometries that redirect airflow or redistribute weight, then propulsive efficiency is improved, but device complexity increases
Solution Approach 1:
The fan blade is divided into multiple functional segments: the ring airfoil structure, the slat mechanism, and the spring elements. Each segment performs a specific function - the ring airfoil generates lift, the slats control airflow separation, and the springs provide passive actuation. This segmentation allows for optimized performance without requiring complex integrated geometries throughout the entire blade structure.
Solution Approach 2:
The slat mechanism is designed to be dynamically adjustable through passive spring actuation. The slats can change their position relative to the ring airfoil based on operating conditions, allowing the blade geometry to adapt dynamically rather than being fixed. This dynamic capability improves propulsive efficiency across varying flight conditions without requiring complex active control systems.
2Productivity
If slats are disposed along the leading edge of the ring airfoil to optimize airflow, then propulsive efficiency is improved, but weight increases
Solution Approach 1:
The slat mechanism is designed to be self-actuating through passive spring elements that automatically adjust the slat position based on aerodynamic loads and operating conditions. This self-service mechanism eliminates the need for complex actuators, motors, or control systems that would significantly increase blade weight. The springs provide the necessary actuation force using only the aerodynamic environment and structural elasticity.
Solution Approach 2:
The slat mechanism changes the aerodynamic parameters of the leading edge by adjusting the slat angle and position. This parameter change allows for optimized airflow attachment and reduced drag across different operating conditions. The ability to vary these aerodynamic parameters passively provides efficiency improvements without the weight penalty of active control systems.
3Object-generated harmful factors
If the slats are configured to close along the axial direction under load, then drag is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The spring actuated slat mechanism automatically adjusts the slat position in response to aerodynamic loads and operating conditions. This self-adjusting capability compensates for manufacturing tolerances and variations, as the system finds its optimal position dynamically rather than requiring precise pre-setting. The passive mechanism adapts to actual operating conditions, reducing the impact of manufacturing precision limitations.
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 solution enhances propulsive efficiency, reduces blade weight, and extends the life of fan blade systems by optimizing airflow and structural integrity through the use of cambered ring airfoils and passive leading edge slats that adjust dynamically with operating conditions.
Implementation Method 1
The one or more slats may be joined to the leading edge of the ring airfoil by a plurality of springs
Data Source
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AI summary
A fan system includes a rotor having plurality of blades and a ring airfoil, the plurality of blades being rotatably joined to a hub and the ring airfoil. The fan system may include a second contra-rotationally disposed rotor having a plurality of blades and a ring airfoil. The first and second ring airfoils having a cambered shape and an angle of attack between about -5 degrees and about 45 degrees. Passive leading edge slats are attached to the ring airfoil and are configured to open and close using springs.