Off-Centre Butterfly Valve for Aircraft Compressor Bleeding
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Solution Overview
Problem
Existing compressor bleeding systems in aircraft turbine engines face issues with response stability and speed due to friction, air compressibility, and the need for a spring-based mechanical force that is not adaptable to varying compressor pressures, leading to unsuitable second mechanical force intensity.
Innovation Solution
A butterfly valve design with an off-centre axis of rotation, where the second mechanical force is generated by aerodynamic torque from the air flow, proportional to the opening angle and dependent on compressor pressure, replacing the spring-based mechanism to enhance response speed and stability across varying pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a spring-based mechanical force is used to return the butterfly to the open position, then the valve structure is simple, but the second mechanical force intensity is not adaptable to varying compressor pressures
Solution Approach 1:
The system uses the air flow from the compressor itself to generate the aerodynamic torque that provides the second mechanical force. The off-centre axis of rotation causes the air flow to naturally create a moment that returns the butterfly to the open position, making the system self-adapting to varying compressor pressures without requiring external springs or additional mechanical components.
2Reliability
If a dual-acting piston with adjustable pressure force is used, then the butterfly can be opened and closed controllably, but significant frictions and air compressibility cause non-linear phenomena impeding response stability
Solution Approach 1:
The invention extracts and eliminates the dual-acting piston mechanism that caused friction and compressibility problems. Instead, it uses a single-acting piston where the return force is provided by aerodynamic torque from the off-centre axis design, removing the source of non-linear phenomena while maintaining controllable operation.
3Speed
If the second mechanical force is provided by a spring, then the valve structure is straightforward, but the force intensity is fixed and unsuitable for rapid valve opening during pressure surges
Solution Approach 1:
The invention changes the parameter of the second mechanical force from a fixed spring force to a variable aerodynamic torque that changes with compressor pressure and butterfly opening angle. This allows the force to automatically increase during pressure surges, enabling rapid valve opening while adapting to varying operating conditions.
4Force
If the axis of rotation is centred on the butterfly, then the valve structure is simple, but no aerodynamic torque is generated to provide the second mechanical force
Solution Approach 1:
The invention introduces asymmetry by positioning the axis of rotation off-centre relative to the butterfly. This asymmetric positioning creates a moment arm that allows the air flow to generate aerodynamic torque, providing the necessary second mechanical force while maintaining a simple structural design without complex 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
This design improves response time and stability by adapting the second mechanical force to compressor pressure, allowing rapid valve opening during pressure surges and maintaining stability across the turbine engine's operating range.
Implementation Method 1
the axis of rotation is off-centre relative to a median segment of the butterfly such that the air in the channel generates an aerodynamic torque on the butterfly, the aerodynamic torque inducing, via the linking means, the second mechanical force on the actuation member
Data Source
AI summary
The invention relates to a butterfly valve (24) for bleeding a compressor for an aircraft turbine engine, the valve including a valve body (32), a butterfly (36), and a device (42) for controlling the angular position of the butterfly, the device (42) including a mobile actuation member (64) connected to the butterfly by a link (70), the member (64) being subjected: to a first adjustable pressure force (F1) applied by air from the compressor, the first force (F1) returning the butterfly (36) to a closed position; and to a second mechanical force (F2) returning the butterfly (36) to an open position, and coming from an aerodynamic torque (C) applied by the air to the butterfly (36), of which the axis of rotation (38) is off-centre relative to the butterfly.