Fuel Pump Valve Flow Segmentation for Gas Turbine Engine
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Solution Overview
Problem
In gas turbine engines, existing fuel pumping systems face inefficiencies as the servo gear pump requires high flow at startup but reduces flow under steady state, while the main gear pump increases fuel flow needs over time, leading to inefficiencies in fuel distribution and increased pump size with increasing accessory complexity.
Innovation Solution
A fuel supply system with a first pump for the combustion chamber, a second pump for accessory actuators, and a valve with bias force that adjusts flow between the pumps based on pressure conditions, allowing the servo gear pump to supplement the main gear pump only when downstream pressure exceeds the bias force, optimizing fuel distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the servo gear pump is sized to provide high flow at startup, then adequate fuel is delivered to accessory actuators during early operation, but the pump becomes oversized and inefficient under steady state conditions
Solution Approach 1:
The fuel delivery function is segmented between two pumps: the servo gear pump handles accessory actuator fuel needs, while the main gear pump handles combustion chamber fuel needs. This segmentation allows each pump to be optimized for its specific function and operating conditions, preventing the servo pump from being oversized for steady-state combustion fuel delivery.
Solution Approach 2:
The system dynamically adjusts fuel flow distribution between the two pumps based on operating conditions. The minimum pressure valve dynamically opens or closes depending on whether the servo pump pressure exceeds the spring bias force, allowing the system to adapt fuel delivery to match varying operational demands without requiring an oversized pump.
2Productivity
If the minimum pressure valve opens early, then the servo gear pump supplements combustion fuel delivery, but the accessory actuators do not receive adequate fuel pressure during startup
Solution Approach 1:
The minimum pressure valve acts as an intermediary component that mediates between the servo gear pump output and the combustion chamber fuel line. It selectively connects or disconnects the servo pump from the combustion fuel delivery based on pressure conditions, ensuring that accessory actuators receive adequate pressure while preventing premature servo pump supplementation that would compromise actuator performance.
3Productivity
If the valve allows servo pump flow to supplement combustion fuel continuously, then adequate fuel is delivered to the combustion chamber, but fuel distribution efficiency decreases under varying operating conditions
Solution Approach 1:
The system incorporates pressure-based feedback through the minimum pressure valve mechanism. The valve monitors servo pump output pressure and only allows supplementation of combustion fuel delivery when pressure exceeds the spring bias force threshold. This feedback mechanism ensures efficient fuel distribution by preventing servo pump flow from entering the combustion line when pressure is insufficient, avoiding energy waste and improper fuel atomization.
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
This solution ensures efficient fuel delivery by adjusting flow between pumps based on system conditions, reducing the size of the servo gear pump and optimizing fuel distribution to both combustion and accessory actuators, enhancing operational efficiency and reducing pump size requirements.
Implementation Method 1
a valve having a first position allowing flow from said first pump to be delivered to the first use, but also routing some flow from said first pump to supplement fuel flow from said second pump until a pressure downstream of said second pump increases to a pressure at which the valve moves to a second position
Implementation Method 2
said valve includes a bias force which biases a valve spool in opposition to the pressure downstream of said second pump
Data Source
Figure 1~2
Figure 3
AI summary
A fuel supply system (50) for a gas turbine engine (40) has a first pump (26) for delivering fuel to a first use (72) on a gas turbine engine, and a second pump (24) for delivering fuel to a second use on the gas turbine engine. A valve (52) allows flow from the first pump to be delivered to the first use, but also routes some flow from the first pump to supplement fuel flow from the second pump until a pressure downstream of the second pump increases. The valve then allows flow from the second pump to flow to the first use to supplement the flow from the first pump.