Aircraft Turbine Discharge Device Scooping Gate Overspeed Prevention
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Solution Overview
Problem
Current turbine engine discharge devices fail to effectively prevent overspeeding of the turbine rotor due to shaft breakage, particularly when the breakage occurs in the fan shaft or internal reduction gear components, leading to potential destruction of the reduction gear and inadequate axial movement to trigger existing 'feathering' mechanisms.
Innovation Solution
A discharge device with a scooping gate mechanism is implemented between the combustion chamber and the low-pressure turbine, which can divert primary flow upon detecting overspeeding, using a valve system that pivots to divert gases radially and is controlled by pyrotechnic, hydraulic, or electrical means to cut off fuel supply, ensuring the low-pressure turbine is not driven by combustion gases and preventing overspeeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing discharge devices with feathering mechanisms are used, then axial movement of the turbine shaft can trigger the mechanism, but the mechanism fails to prevent overspeeding when breakage occurs in the fan shaft or internal reduction gear components without sufficient axial movement
Solution Approach 1:
The invention extracts the discharge function from the traditional feathering mechanism tied to axial movement. The scooping gate is directly connected to the turbine rotor and can divert primary flow regardless of axial movement, separating the overspeeding prevention function from the constraint of feathering mechanism activation.
Solution Approach 2:
The scooping gate serves multiple functions: it acts as both a discharge device and a direct overspeeding prevention mechanism. It can divert primary flow in response to overspeeding detected by various means (tachometer, over-speed governor, or centrifugal force), making it universally applicable to different breakage scenarios including fan shaft and reduction gear failures.
2Reliability
If complex actuator control systems are implemented to prevent overspeeding, then reliable protection is achieved, but device complexity increases significantly
Solution Approach 1:
The scooping gate is designed to automatically respond to overspeeding conditions without requiring complex external actuator control systems. The gate can be unlocked and activated by simple detection means (tachometer, over-speed governor, or centrifugal force), and the turbine rotor itself drives the gate through its rotation, making the system self-regulating and inherently simple.
3Reliability
If the scooping gate is positioned downstream of the high-pressure turbine, then it can effectively divert primary flow to prevent overspeeding, but the device complexity and integration requirements increase
Solution Approach 1:
The invention merges the scooping gate with the turbine rotor structure itself. The gate is directly connected to the turbine rotor and moves with it, eliminating the need for separate actuator systems and complex integration. The gate forms an integral part of the turbine assembly, simplifying the overall device structure while maintaining effective overspeeding prevention.
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 effectively prevents overspeeding by diverting primary flow and cutting off fuel supply, thereby reducing the risk of turbine rotor damage and allowing for safer operation in case of shaft or reduction gear breakage, without the need for complex actuator control systems.
Implementation Method 1
a scooping gate able to be unlocked in order to divert the primary flow
Implementation Method 2
controlled by pyrotechnic, hydraulic, or electrical means to cut off fuel supply
Data Source
AI summary
Aircraft turbine engine, including at least one first compressor, an annular combustion chamber and at least one first turbine, which define a first flow duct for a primary flow. Between the combustion chamber and the first turbine is a device for discharging at least part of the primary flow.