Manifold Select Metering System for Fuel Redundancy
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Solution Overview
Problem
Multi-stage gas turbine fuel systems face challenges in maintaining prime reliability of the primary combustor stage without incurring excessive weight and cost due to the redundancy of electro-hydraulic servo valves (EHSVs), especially when failures affect the main fuel metering system, and there is a need for a solution that can switch fuel supply between manifolds to ensure continuous operation.
Innovation Solution
A manifold select system utilizing a transfer electro-hydraulic servo valve (EHSV), a discharge select valve (DSV) with a multi-land piston, and throttling valves to switch metered fuel supply from a secondary manifold to a primary manifold in case of failure, while isolating the secondary manifold, ensuring prime reliability without the need for additional redundant components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant EHSVs are added to the primary fuel metering system to ensure continued operation, then reliability is improved, but weight and cost increase
Solution Approach 1:
The secondary fuel metering system, originally designed solely for secondary combustor stages, is configured to provide backup fuel supply to the primary combustor stage. This multi-functional capability allows a single system to serve multiple purposes: normal secondary stage operation and emergency primary stage support, eliminating the need for dedicated redundant components.
Solution Approach 2:
A transfer valve is introduced as an intermediary component that enables switching between primary and secondary fuel metering systems. This transfer valve acts as a mediator that can redirect fuel flow from the secondary system to the primary manifold when needed, providing reliability without requiring duplicate EHSV components.
2Reliability
If redundant EHSVs are added to the primary fuel metering system to ensure continued operation, then reliability is improved, but cost increases
Solution Approach 1:
The secondary fuel metering system is designed to serve dual purposes: normal operation for secondary combustor stages and backup operation for primary combustor stage. This eliminates the need to manufacture additional redundant EHSV components, reducing overall system cost while maintaining reliability.
Solution Approach 2:
The backup fuel supply function is merged into the existing secondary fuel metering system rather than being implemented as a separate redundant system. This consolidation reduces component count and manufacturing cost while achieving the same reliability objective.
3Reliability
If a transfer system with transfer valve is implemented to switch between redundant EHSVs, then reliability is improved, but device complexity increases
Solution Approach 1:
A transfer valve serves as a simple intermediary component that enables switching between primary and secondary fuel metering systems. This single valve provides the necessary switching capability without introducing complex control logic or additional components, maintaining system simplicity while improving reliability.
4Reliability
If the secondary fuel metering system is used to supply the primary manifold during failure, then reliability is improved, but fuel flow control complexity increases
Solution Approach 1:
The transfer valve acts as a straightforward intermediary that switches fuel flow between primary and secondary metering systems. By using this single switching component rather than a complex multi-valve arrangement, the system achieves reliable fuel flow redirection with minimal added 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 system effectively maintains prime reliability of the primary fuel manifold by supplying metered fuel from a secondary system during failures, reducing weight and cost by eliminating the need for redundant EHSVs and ensuring efficient fuel flow with minimal pressure loss and leakage prevention.
Implementation Method 1
A manifold select system utilizing a transfer electro-hydraulic servo valve (EHSV), a discharge select valve (DSV) with a multi-land piston
Implementation Method 2
The DSV has a multi-land piston that is configured to switch a throttling valve control pressure from the second throttling valve to the first throttling valve
Data Source
AI summary
A system and method of providing prime reliability of a primary fuel manifold upon failure of a primary fuel metering system by providing metered fuel from a secondary fuel metering system are provided. The system utilizes a transfer electro-hydraulic servo valve (EHSV), a discharge select valve (DSV) coupled to the EHSV, and a pair of throttling valves positioned between secondary fuel metering system and the primary and secondary fuel manifolds. The DSV has a multi-land piston that switches a control pressure and a shutoff pressure between the pair of throttling valves to transfer the supply of metered fuel of the secondary fuel metering system from the secondary fuel manifold to the primary fuel manifold. The output pressurizing valve of the failed primary fuel metering system is also closed to isolate the failed primary fuel metering system from the primary fuel manifold.