Electric Gear Pump for Aero-Engine Fuel Systems
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Solution Overview
Problem
Aero-engine fuel pumping units face challenges in varying speed to reduce heat rejection and pump wear, and require rotating seals for mechanical drive shafts, which are inefficient and prone to leakage.
Innovation Solution
The use of electrical motors to drive the gear pump independently of engine speed, eliminating the need for rotating seals and integrating motors within the pump for cooling and compact design, with variable frequency motor drives and a control unit for redundancy and power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gear pump is driven by a mechanical shaft from the engine accessory gearbox, then the pump operates at fixed speed relative to engine speed, but this requires a rotating seal that is prone to leakage and reduces reliability
Solution Approach 1:
The patent replaces the mechanical shaft-driven system with an electric motor-driven system. The electric motor eliminates the need for a rotating seal while providing reliable power transmission to the gear pump, directly resolving the reliability issue caused by seal leakage.
Solution Approach 2:
The patent extracts and removes the rotating seal component from the system by using an electric motor that can be sealed within the pump housing. This eliminates the leakage source while maintaining the mechanical drive function through magnetic coupling or direct sealed mounting.
2Temperature
If the pump operates at fixed speed tied to engine speed, then the design is simple, but this prevents variation of pump speed to reduce heat rejection and fuel heating
Solution Approach 1:
The patent implements variable speed operation by using an electric motor with adjustable rotational speed. This allows the pump to operate at optimal speeds for different conditions, reducing excessive fuel heating and improving temperature management during various flight phases.
Solution Approach 2:
The patent changes the operational parameter of pump speed from fixed to variable. By controlling the electric motor speed, the system can adjust fuel flow rate and recirculation, thereby controlling the heat rejection and final fuel temperature to optimal levels.
3Productivity
If the pump is designed to provide sufficient flow at maximum take-off, then the pump meets peak demand, but this results in excess flow recirculation during normal operation that heats the fuel
Solution Approach 1:
The patent uses variable speed control to match the pump output to actual fuel demand. During normal operation, the pump speed is reduced to provide only the required flow, minimizing recirculation and the associated heat generation, while still being capable of meeting peak demand when needed.
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 allows for reduced heat rejection, increased fuel cooling capacity, and enhanced pump reliability by minimizing recirculated flow and eliminating the need for rotating seals, while maintaining efficient operation and fault tolerance.
Implementation Method 1
the electrical motors can be cooled by the pumped fuel
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A gear pump has first and second meshing gears for pumping a fluid. The gear pump further has a first electrical motor having a first rotor, a first stator and first coil windings. The gear pump further has a second electrical motor having a second rotor, a second stator and second coil windings. The first rotor is operatively connected to the first gear and the second rotor is operatively connected to the second gear such that each gear is rotated by its respective rotor. The first and second coil windings are energised by respective and separate first and second electrical power circuits such that the first and second meshing gears can be driven independently of each other.