Variable Displacement Piston Pump for Gas Turbine Fuel Systems
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Solution Overview
Problem
Gas turbine engine fuel supply systems face challenges in minimizing self-heating, which leads to thermodynamic inefficiencies due to excess fuel recirculation and waste heat generation, particularly in systems with gear pumps that require bypass subsystems to maintain pressure drops across fuel metering units.
Innovation Solution
A fluid supply system utilizing a variable displacement piston pump and a pump compensator valve that adjusts the pump discharge pressure between a minimum and a floating ceiling pressure based on the highest metered flow pressure, ensuring efficient fuel delivery while minimizing self-heating by dynamically responding to downstream pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a gear pump is used to maintain pressure drop across the fuel metering unit, then sufficient pressure is maintained, but fuel self-heating increases due to excess flow recirculation
Solution Approach 1:
The patent employs a variable displacement piston pump that dynamically adjusts its discharge pressure in response to downstream pressure changes. The pump controller continuously monitors downstream pressure and modifies pump displacement to maintain optimal pressure differentials without excessive recirculation, thereby reducing fuel self-heating while ensuring adequate pressure across the fuel metering unit.
Solution Approach 2:
The system changes the operating parameters of the pump by varying displacement based on downstream pressure conditions. This allows the pump to operate at optimal efficiency points across different flight conditions, maintaining necessary pressure drops while minimizing energy waste and fuel heating through intelligent parameter adjustment.
2Stress or pressure
If a bypass subsystem is added to maintain pressure drop across the fuel metering unit, then pressure is maintained, but system complexity and waste heat increase
Solution Approach 1:
The patent extracts the pressure regulation function from a separate bypass subsystem and integrates it directly into the piston pump's variable displacement mechanism. This eliminates the need for complex external bypass circuits while maintaining the necessary pressure differentials across the fuel metering unit, thereby reducing system complexity.
Solution Approach 2:
The variable displacement piston pump performs multiple functions: it provides pressure regulation, flow control, and adaptation to downstream conditions all through a single integrated mechanism. This multi-functionality replaces what would otherwise require separate bypass subsystems, simplifying the overall system architecture.
3Stability of the object's composition
If excess flow is recirculated to maintain pressure, then pressure stability is improved, but energy efficiency deteriorates due to waste heat generation
Solution Approach 1:
The patent implements a feedback control system where the pump controller continuously monitors downstream pressure and adjusts pump displacement in real-time. This feedback mechanism maintains stable pressure differentials across the fuel metering unit by precisely matching supply to demand, eliminating the need for continuous excess flow recirculation and thereby improving energy efficiency.
Solution Approach 2:
The variable displacement piston pump dynamically adapts its operation to match actual fuel demand conditions, adjusting displacement to maintain stable pressure without excessive recirculation. This dynamic response ensures pressure stability while minimizing energy waste by only recirculating the minimum necessary flow.
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 reduces self-heating and enhances thermodynamic efficiency by continuously adjusting pump discharge pressure to match downstream demands, thereby optimizing fuel delivery and reducing waste heat in gas turbine engine fuel supply systems.
Implementation Method 1
a variable displacement piston pump configured to supply a fluid at a pump discharge pressure
Implementation Method 2
a pump compensator valve fluidically coupled with the one or more fuel metering units to receive the fluid therefrom at the metered flow discharge pressures and configured to continuously, either fluidically or mechanically, adjust the pump discharge pressure
Data Source
AI summary
Methods and fluid supply systems are provided for supplying fluids while adjusting a pump discharge pressure to compensate for downstream pressure changes. The fluid supply system comprises a variable displacement piston (VDP) pump configured to supply a fluid at a pump discharge pressure, fuel metering units (FMUs) downstream of the VDP pump, each of the FMUs configured to receive the fluid from the VDP pump at the pump discharge pressure and supply the fluid at metered flow discharge pressures, and a pump compensator valve fluidically coupled with the FMUs to receive the fluid therefrom at the metered flow discharge pressures and configured to continuously, either fluidically or mechanically, adjust the pump discharge pressure of the VDP pump between a higher of a minimum pump discharge pressure and a floating ceiling pump discharge pressure, the floating ceiling pump discharge pressure based on a highest of the metered flow discharge pressures.