Fault-Accommodating Flow Scheduling Valve for Primary Spring Failure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing flow scheduling valves in multi-stage combustors of gas turbine engines fail to accommodate mains FSV failures effectively, leading to hot streaks and potential nozzle and turbine damage, and existing solutions require engine shutdown or reduction in thrust.
Innovation Solution
A fault-accommodating flow scheduling valve with a shuttle valve and primary valve member, actuated by compression-loaded springs, automatically adjusts to prevent fuel flow when primary spring failure occurs, using balance springs to maintain valve operation and prevent hot streaks without relying on external measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional flow scheduling valve is used in multi-stage combustors, then the valve structure is simple, but the valve cannot accommodate mains FSV failures leading to hot streaks and potential nozzle and turbine damage
Solution Approach 1:
The valve is segmented into two independent sealing systems: a primary valve member with primary spring for normal operation, and a shuttle valve member with balance springs for failure accommodation. This segmentation allows each component to perform its specific function independently, achieving reliable failure accommodation without requiring complete system redesign
Solution Approach 2:
The balance springs are pre-configured to automatically engage the shuttle valve member when primary spring pressure drops below threshold levels. This beforehand cushioning mechanism prevents catastrophic failure by having the backup sealing system ready to activate immediately upon primary spring failure, eliminating hot streaks before they can cause damage
2Reliability
If existing solutions for detecting FSV failure are implemented (pressure variation measurements or thermocouple measurements), then failure detection capability is improved, but the system requires engine shutdown or thrust reduction
Solution Approach 1:
The valve performs self-diagnosis and self-repair through the interaction between primary spring pressure and balance spring activation. When primary spring pressure drops, the balance springs automatically engage the shuttle valve member to close the valve, eliminating the need for external detection systems or engine shutdown procedures
Solution Approach 2:
The balance springs act as an intermediary mechanism between the primary spring failure condition and the valve closure action. They sense the pressure drop and mediate the transition to the backup sealing mode, enabling automatic failure accommodation without external intervention or loss of engine productivity
3Reliability
If the primary spring fails in a conventional FSV, then the valve cannot maintain sealing, but adding a shuttle valve mechanism increases device complexity
Solution Approach 1:
The primary valve member and shuttle valve member are merged into a single integrated valve body with shared inlet and outlet ports. Both sealing systems operate within the same structural framework, allowing the shuttle valve to take over sealing duties when the primary valve fails, achieving redundancy without proportionally increasing overall 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
The valve automatically accommodates primary spring failures and blockages, preventing hot streaks and nozzle damage, and maintains engine operation without the need for shutdown or thrust reduction.
Implementation Method 1
a compression-loaded primary spring which acts on the primary valve member to urge the primary valve member into engagement with the outlet-side sealing face
Implementation Method 2
first and second compression-loaded balance springs which act on the shuttle valve member, the first balance spring acting between a first side of the shuttle valve member and the primary valve member, and the second balance spring acting on an opposite, second side of shuttle valve member
Data Source
AI summary
A fault-accommodating flow scheduling valve has a first inlet, outlet, and orifice therebetween. The valve has a shuttle valve member on the orifice inlet side, a primary valve member on the orifice outlet side, a compression-loaded primary spring, and first and second compression-loaded balance springs. Below a threshold differential pressure, the primary valve member engages with the outlet-side sealing face to close the valve while the shuttle valve member is spaced from the inlet-side sealing face, and on failure of the primary spring, the primary valve member moves from the outlet-side sealing face but the shuttle valve member closes the valve. Above the threshold differential pressure, the primary valve member opens the valve while the shuttle valve member remains spaced, and on failure of the primary spring, the primary valve member moves further from the outlet-side sealing face but the shuttle valve member closes the valve.