Multi-Pump Gas Turbine Fuel Supply System for High Pressure Zones
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Solution Overview
Problem
Existing gas turbine engine fuel supply systems waste energy by recirculating excess fuel, leading to high fuel temperatures and are unable to supply the higher fuel pressures required by modern combustor designs with multiple zones, as they rely on a single positive displacement pump.
Innovation Solution
A fuel supply system comprising a primary gear pump, a secondary gear pump, a supercharger pump, a pump control valve, and a pump bypass valve, which allows for simultaneous operation of multiple pumps to supply fuel at varying pressures to multiple combustor zones, with the supercharger pump activated only during high demand conditions to minimize energy waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a single positive displacement pump is used to supply fuel, then the system structure is simple and reliable, but the fuel pressure is insufficient for modern multi-zone combustors
Solution Approach 1:
The fuel supply system is segmented into multiple independent pump units (first gear pump, second gear pump, third gear pump), each capable of operating autonomously. This segmentation allows the system to achieve higher pressures by combining multiple pumps in parallel while maintaining structural simplicity through modular design, directly resolving the contradiction between pressure requirements and system complexity.
Solution Approach 2:
Multiple gear pumps are merged in parallel configuration to collectively supply fuel to the multi-zone combustor. The combined output of the first, second, and third gear pumps delivers the high pressure and flow rate required by modern combustors, while the modular merging approach keeps each pump unit simple and manageable, thus resolving the pressure-complexity contradiction.
2Productivity
If the main fuel pump is sized for max demand, then fuel flow is sufficient during start-up and takeoff, but excess fuel is supplied during idle and cruise conditions
Solution Approach 1:
The fuel supply system transitions from a static single-pump design to a dynamic multi-pump configuration where pumps can be selectively activated based on engine operating conditions. During idle and cruise, only one pump operates; during high demand, additional pumps are engaged. This dynamic adaptability matches fuel supply to actual demand, eliminating energy waste from excessive fuel generation while maintaining sufficient productivity across all operating modes.
Solution Approach 2:
The system changes operational parameters by varying the number of active pump units according to engine demand. The controller monitors operating conditions and adjusts the configuration from single-pump operation (low demand) to multi-pump operation (high demand), optimizing the balance between fuel supply productivity and energy consumption across different flight phases.
3Quantity of substance
If excess fuel is recirculated back to the low pressure pump inlet, then fuel flow is maintained, but energy is wasted and fuel temperature increases
Solution Approach 1:
The harmful recirculation loop is extracted and replaced by a selective pump activation strategy. Instead of recirculating excess fuel through the low-pressure pump, the system simply deactivates unnecessary high-pressure pumps based on actual fuel demand. This eliminates the energy-wasting recirculation process while maintaining proper fuel flow quantity through demand-matched pump operation.
Solution Approach 2:
The system converts the potential harm of excess fuel generation into a benefit by using the same pump infrastructure to precisely match supply with demand. The modular pump design allows the system to benefit from having multiple pumps available while avoiding the harm of energy waste by selectively operating only the necessary number of pumps, transforming the redundancy from a liability into a controllable asset.
4Adaptability or versatility
If a single metering circuit is used, then the system is simple, but it cannot supply fuel to multiple separate combustor zones
Solution Approach 1:
The fuel distribution system is segmented into multiple independent metering circuits, with each circuit dedicated to a specific combustor zone. This segmentation allows each circuit to be optimized for its zone while maintaining overall system simplicity through modular design, enabling multi-zone coverage without excessive complexity.
Solution Approach 2:
Each gear pump unit is designed as a universal module that can supply fuel to any combustor zone through the appropriate metering circuit. This multi-functionality allows the same pump design to serve multiple purposes across different operating conditions and zones, achieving versatility in combustor coverage while keeping individual pump and circuit designs simple and standardized.
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 reduces energy waste and efficiently supplies higher fuel pressures to separate combustor zones, optimizing fuel delivery by using multiple pumps in parallel and regulating pressure to meet the demands of different operating conditions.
Implementation Method 1
The main fuel pump is typically implemented using a positive displacement pump that is driven directly by the engine gearbox
Implementation Method 2
The pump bypass valve is in fluid communication with the primary gear pump outlet and is configured to regulate fuel pressure at the primary gear pump outlet to one of a plurality of preset differential pressures above one of a plurality of fuel load pressures
Data Source
AI summary
A gas turbine engine fuel supply system includes a primary gear pump, a secondary gear pump, and a pump bypass valve. The primary gear pump always actively delivers fuel to the downstream fuel system, and is sized to supply 100% of the burn flow needed at a select low demand condition. The secondary gear pump is sized to make up the remainder of the flow at high demand conditions, and actively delivers fuel to the downstream fuel system only during those conditions. To supply discharge fuel pressures in excess of gear pump capability, a supercharger pump is disposed upstream of the primary and secondary gear pumps. The pump bypass valve is configured to regulate fuel pressure at the primary gear pump outlet to one of a plurality of preset differential pressures above one of a plurality of fuel load pressures and prevents reverse pressurization of the gear pumps.