Dual-Pump Metering Pump Design for High-Temperature Fuel Delivery
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Solution Overview
Problem
Existing fuel metering systems in modern military jet engines face challenges with thermal management due to high fuel temperatures, requiring larger motor and controller sizes and higher power consumption, while also needing economically viable solutions.
Innovation Solution
A dual-pump system with a first pump providing 10-15 times the pressure of a second pump, combined with a pressure regulating valve and a mass flow meter for feedback, reduces motor and controller size by offloading power requirements to a mechanically-driven high-speed first pump stage, enhancing accuracy and system health monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pump system is used to provide both pressure and metering functions, then the system structure is simple, but the motor and controller sizes increase and power consumption increases
Solution Approach 1:
The fuel delivery system is segmented into two separate pump stages: a first pump (mechanically driven) that provides high pressure (10-15 times the pressure of the second pump), and a second pump (electrically driven) that provides precise metering at lower pressure. This segmentation allows the electric motor and controller to be sized for the smaller metering function rather than the full power requirement, significantly reducing their size and power consumption while maintaining system functionality.
2Device complexity
If a single pump system is used to provide both pressure and metering functions, then the system structure is simple, but power consumption increases
Solution Approach 1:
The system divides power delivery into two stages: the first pump (mechanically driven by the engine) handles the energy-intensive pressure generation, while the second pump (electrically driven) handles only the energy-efficient metering function. This segmentation reduces overall power consumption by the electrical system while maintaining the required fuel delivery performance.
Solution Approach 2:
The first pump acts as an intermediary that pre-pressurizes the fuel before it reaches the second pump. By providing this intermediate pressure boost, the first pump reduces the workload on the electric motor and controller, thereby reducing their power consumption requirements.
3Power
If the first pump provides 10-15 times the pressure of the second pump, then motor and controller size is reduced, but the pressure regulation requirement increases
Solution Approach 1:
A pressure regulating valve is introduced as an intermediary component between the first pump and the second pump. This valve mediates the pressure transition by reducing the high pressure from the first pump to the appropriate level for the second pump, enabling the second pump to operate at optimal pressure conditions while maintaining the pressure reduction benefit.
Solution Approach 2:
The pressure regulation function is extracted as a separate, dedicated component (pressure regulating valve) rather than being integrated into the pump system. This allows the pressure regulation requirement to be addressed independently, enabling the second pump to focus solely on metering without needing to handle extreme pressure variations.
4Measurement precision
If a mass flow meter is added for feedback and trimming, then fuel delivery accuracy is improved, but device complexity increases
Solution Approach 1:
A mass flow meter is installed downstream of the second pump to measure actual fuel flow. The measured flow information is fed back to a speed control system that adjusts the rotational speed of the second pump to trim steady-state fuel delivery. This feedback loop significantly improves fuel delivery accuracy by compensating for variations in pump performance and operating conditions.
Solution Approach 2:
The system uses its own output (fuel flow measurement) to automatically adjust and optimize its performance. The mass flow meter monitors the actual fuel delivery, and the speed control system uses this information to self-correct any deviations from the desired fuel flow, enabling the system to maintain high accuracy without external intervention.
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 achieves reduced electric motor and controller size, improved efficiency, and decreased power consumption, while maintaining accurate fuel delivery and thermal management under high fuel temperatures.
Implementation Method 1
The first pump is configured for distributing fuel from the fuel tank throughout the fuel system. The second pump is fluidly coupled to the first pump and configured for metering fuel to an engine.
Implementation Method 2
A fixed pressure rise provided by regulator 108 across the second pump 106 enables increased accuracy in open loop fuel metering control by reducing variation in volumetric efficiency.
Implementation Method 3
A mass flow meter 110 is located downstream of the second pump 106 in order to provide feedback to a speed control of the second pump 106 and to trim steady-state fuel delivery to improve the accuracy and provide shutoff functionality.
Data Source
Figure 1
Figure 2
AI summary
A fuel system including a fuel tank (102), a first pump (104) fluidly coupled to the fuel tank configured for distributing fuel from the fuel tank throughout the fuel system, and a second pump fluidly coupled to the first pump by a pressure regulating valve (108) and configured for driving fuel to an engine.