Gas Turbine Fuel Shutoff Apparatus with Latching Mechanism
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Solution Overview
Problem
Existing fuel systems for gas turbine engines lack an efficient mechanism to quickly stop fuel flow during engine overspeed events, potentially leading to damage.
Innovation Solution
A fuel flow system incorporating a shutoff apparatus with an engine overspeed electro-mechanical interface device and valves that allow for selective energization to stop fuel flow without operating the metering valve, ensuring rapid shutdown and latching in shutdown mode even when de-energized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the metering valve is used to stop fuel flow, then the fuel flow can be controlled, but the shutdown speed is insufficient and may cause engine damage
Solution Approach 1:
The fuel flow control system is segmented into multiple independent valves: the metering valve for normal flow control and the minimum pressure shut-off valve for emergency shutdown. This segmentation allows the shut-off valve to operate independently at high speed without affecting the metering valve's positioning, resolving the contradiction between shutdown speed and engine safety
Solution Approach 2:
A latch mechanism acts as an intermediary between the shut-off valve and the control system. The latch mechanically holds the shut-off valve in the closed position after actuation, maintaining fuel flow stoppage even when the control system is de-energized, thereby ensuring engine safety while enabling rapid initial shutdown
2Use of energy by moving object
If the shut-off apparatus is de-energized after shutdown, then energy is saved, but the shutdown state may not be maintained
Solution Approach 1:
The latch mechanism is designed to be self-latching, automatically maintaining the shut-off valve in the closed position without requiring continuous external energy input. Once the shut-off valve is actuated, the latch mechanically secures it in place, making the system self-sufficient for maintaining the shutdown state and enabling energy savings while ensuring state stability
Solution Approach 2:
The latch mechanism serves as an intermediary that decouples the control system's energy state from the valve's position state. It translates a brief energization event into a persistent mechanical state, ensuring shutdown stability independent of the control system's power status while allowing energy savings when de-energized
3Speed
If a rapid shutdown mechanism is added, then shutdown speed improves, but system complexity increases
Solution Approach 1:
The minimum pressure shut-off valve is designed to serve multiple functions: normal fuel flow regulation, emergency rapid shutdown, and latching state maintenance. By making this single component multi-functional, the system achieves rapid shutdown capability without adding separate dedicated components for each function, thereby limiting the increase in system complexity
Solution Approach 2:
The latch mechanism is integrated directly into the shut-off valve assembly, combining the shutdown actuation function and the state maintenance function into a single unified component. This merging eliminates the need for separate latch actuators and control circuits, achieving rapid shutdown with minimal additional complexity
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
Enables rapid and reliable shutdown of fuel flow during engine overspeed events, preventing damage and maintaining the shutdown state until the system is manually reset.
Implementation Method 1
The engine overspeed electro-mechanical interface device is selectably energized to pressurize fluid to operate the engine overspeed valve via pressurization of the fluid
Implementation Method 2
A minimum pressure shut-off valve is fluidly connected to the one or more pumps
Data Source
AI summary
A fuel flow system for a gas turbine engine includes a fuel inlet to admit a flow of fuel into the fuel flow system and a fuel outlet to direct the flow of fuel to the gas turbine engine from the fuel flow system. One or more pumps are positioned along a fuel flow path connecting the fuel inlet to the fuel outlet. A metering valve is in flow communication with the one or more pumps to meter the flow of fuel. A minimum pressure shut-off valve is fluidly connected to the one or more pumps, and a shutoff apparatus configured to permit selective energizing to stop the flow of fuel from the fuel outlet without operation of the metering valve.