Stability Bleed Valve Shutoff Using Pressure Divider and Shuttle Valve
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Solution Overview
Problem
Existing stability bleed valves in gas turbine engines face challenges in maintaining engine stability during idle and sub-idle conditions, requiring improved designs to enhance stability margins.
Innovation Solution
An inline bleed air valve with an electromechanical control system, incorporating a shuttle valve and an orifice divider network, which adjusts the valve's operation based on pressure ratios to optimize closure and minimize leakage, is introduced. The valve features a pneumatic flow path with a sleeved piston and spring mechanism, along with a solenoid for active closure and a pressure divider network to manage pressure ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional spring-loaded poppet valve is used, then the valve structure is simple, but the engine stability margin during idle and sub-idle conditions is insufficient
Solution Approach 1:
The valve system is divided into multiple functional components: a poppet valve for basic flow control, a pressure divider network with separate inlet and outlet orifices for pressure regulation, and an electromechanical control valve for active control. This segmentation allows each component to specialize in specific functions, improving overall stability while maintaining reasonable complexity through modular design.
Solution Approach 2:
A pressure divider network is introduced as an intermediary between the compressor outlet and the poppet valve. This network uses separate inlet and outlet orifices to create distinct pressure zones, enabling precise control of the pressure differential across the poppet valve. The intermediary pressure regulation system enhances stability margins by smoothly managing pressure transitions during idle and sub-idle conditions.
2Reliability
If the valve closes completely to prevent leakage, then engine stability improves, but the valve may fail to maintain closure at high altitudes and low pressures
Solution Approach 1:
The pressure divider network provides continuous feedback about the pressure differential across the poppet valve through its inlet and outlet orifices. This feedback mechanism allows the system to automatically adjust to varying operating conditions, including high altitude and low pressure environments, maintaining reliable valve closure by responding to real-time pressure changes rather than relying on fixed mechanical settings.
Solution Approach 2:
The system changes the pressure parameters across the valve by using the pressure divider network to create and maintain appropriate pressure differentials. The separate inlet and outlet orifices allow independent pressure regulation, enabling the valve to adapt its closure characteristics across a wide range of operating conditions including high altitude operations where ambient pressure varies significantly.
3Measurement precision
If a pressure divider network with separate inlet and outlet orifices is added, then pressure ratio control improves, but the valve complexity increases
Solution Approach 1:
The pressure divider network is integrated directly into the valve body structure, merging the pressure regulation function with the existing valve assembly. The inlet and outlet orifices are incorporated into the housing design rather than being separate components, reducing overall complexity while maintaining precise pressure ratio control capability.
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 ensures improved engine stability by precisely controlling airflow, reducing leakage, and maintaining valve closure even at high altitudes and low pressures, thereby enhancing engine performance across various operational conditions.
Implementation Method 1
The valves are typically poppet valves, which are spring loaded open and gradually close, via a pressure force acting on the poppet as the engine speeds up during start.
Implementation Method 2
gradually close, via a pressure force acting on the poppet as the engine speeds up during start
Implementation Method 3
The control valve may comprise an electromechanical valve
Data Source
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AI summary
A bleed air valve comprises a piston that moves along a guide, where the piston includes a first surface and an opposing second surface. A pressure divider network includes a divider network inlet having an inlet cross sectional area in fluid communication with a fluid passage, a divider network outlet having an outlet cross sectional area in fluid communication with ambient pressure, and a network chamber in fluid communication with the divider network inlet and the divider network outlet. The network chamber has a pressure value between pressure at the divider network inlet and pressure at the divider network outlet. A shuttle valve includes a shuttle inlet and a shuttle outlet, where the shuttle outlet is in fluid communication with the first surface. An electromechanical valve receives a command signal and in response provides compressed air to an electromechanical valve output that is in fluid communication with the shuttle inlet.