Aircraft Engine Fuel Pump Intermediate Inlet Pressure Management
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Solution Overview
Problem
Existing aircraft engine fuel systems face issues with hot fuel recirculation affecting pump performance and adding weight due to returning fuel to the fuel tank, which is undesirable.
Innovation Solution
A fuel system with a regenerative rotodynamic pump featuring a movable intermediate inlet between the main inlet and outlet, adjustable to manage pressure and recirculate fuel effectively, utilizing an actuator and controller to regulate pressure and optimize fuel flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If hot return fuel is recirculated to the fuel pump inlet or upstream point, then fuel is returned to the fuel system, but pump operational performance deteriorates due to vapor-to-liquid operational issues under depressed inlet conditions
Solution Approach 1:
The patent introduces an intermediate inlet as a mediator between the hot return fuel and the pump's main inlet. This intermediate inlet receives hot return fuel at an intermediate pressure point, allowing heat dissipation and pressure equalization before the fuel enters the pump, thus protecting pump performance while maintaining fuel recirculation functionality
Solution Approach 2:
The fuel recirculation path is segmented into two separate inlets: a main inlet for cold fuel and an intermediate inlet for hot return fuel. This segmentation allows the system to handle hot and cold fuel streams separately, preventing hot fuel from directly affecting pump performance while still enabling effective heat management
2Weight of moving object
If return fuel is sent to the aircraft fuel tank, then fuel weight is reduced in the system, but additional hardware weight is added to bring return fuel to the tank
Solution Approach 1:
The patent merges the fuel recirculation function with the existing pump structure by incorporating an intermediate inlet directly into the pump housing. This eliminates the need for separate return lines and additional hardware to transport fuel back to the tank, reducing overall system weight while maintaining fuel management capabilities
Solution Approach 2:
The pump system serves itself by using its own structure (the intermediate inlet) to receive and manage hot return fuel. The pump handles both cold fuel intake and hot return fuel reception without requiring external hardware systems, making the system self-sufficient and reducing overall hardware weight
3Stress or pressure
If an intermediate inlet is added to the pump, then fuel pressure management is improved, but device complexity increases
Solution Approach 1:
The intermediate inlet is designed with multi-functionality, serving both as a reception point for hot return fuel and as a pressure management mechanism. By combining these functions into a single structural element integrated into the pump housing, the system achieves improved pressure management without proportionally increasing device complexity
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 improves fuel pump performance by managing pressure and reducing weight by efficiently handling recirculated fuel, enhancing operational efficiency and reducing hardware requirements.
Implementation Method 1
the impeller cavity housing at least part of an impeller rotatable about a rotation axis to pump fuel from the main inlet to the outlet
Data Source
AI summary
A liquid fuel system for an aircraft engine includes a first fuel supply conduit hydraulically connected to a fuel source, a second fuel supply conduit hydraulically connected to the engine, a fuel return conduit hydraulically connected to the second fuel supply conduit, and a fuel pump. The fuel pump has a main inlet hydraulically connected to the first fuel supply conduit, an outlet hydraulically connected to the second fuel supply conduit, and an intermediate inlet hydraulically connected to the fuel return conduit. The intermediate inlet is located between the main inlet and the outlet and in use has a pressure between the main inlet pressure and the outlet pressure. A method of supplying a liquid fuel to an aircraft engine is also described.