Aircraft Fuel Tank Cooling Using Wing Fuel Circulation
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Solution Overview
Problem
Commercial aircraft fuel tanks, particularly the center fuel tank, often operate above the Lower Flammability Limit due to heat input from environmental control systems, posing a flammability risk that current nitrogen generation methods are costly and inefficient to manage.
Innovation Solution
A fuel circulation system that draws cold fuel from wing tanks and circulates it through the center fuel tank, combined with insulation to maintain flammability limits, and a control system to automate valve operation based on environmental sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitrogen generation equipment is installed to control flammability risk, then safety is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the harmful heat source (ECS bay) from proximity to the fuel tank by routing hot air away from the tank area, eliminating the need for complex nitrogen generation equipment. This removes the problematic interaction between heat-generating ECS components and fuel storage
Solution Approach 2:
The patent introduces an intermediary thermal management system with insulated barriers and air routing channels between the ECS bay and fuel tank. This intermediary structure prevents direct heat transfer while maintaining system simplicity
2Reliability
If insulation is added to the fuel tank to maintain temperature, then flammability control is improved, but device complexity increases
Solution Approach 1:
The patent merges the insulation requirement into the existing ECS bay structural design, integrating thermal barriers into the fuselage structure itself rather than adding separate insulation components. The fuel tank insulation is combined with the ECS bay wall structure
Solution Approach 2:
The ECS bay structure serves multiple functions: it houses environmental control equipment, provides structural support, and acts as a thermal barrier when properly insulated. This multi-functionality eliminates the need for dedicated insulation structures
3Stability of the object's composition
If the center fuel tank is isolated from cold air exposure, then operational stability is improved, but flammability risk increases
Solution Approach 1:
The patent converts the harmful heat exposure from ECS into a beneficial cooling mechanism by intentionally routing cold air from the ECS bay through the fuel tank area, using the temperature differential to the tank's advantage
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
Maintains the center fuel tank within flammability limits, reducing the need for costly nitrogen generation equipment and enhancing safety by keeping the tank conditions below the Lower Flammability Limit.
Implementation Method 1
A fuel circulation system that draws cold fuel from wing tanks and circulates it through the center fuel tank
Implementation Method 2
combined with insulation to maintain flammability limits
Data Source
AI summary
Commercial aircraft fuel tanks, such as the center wing tank or body tanks, can be subject to explosion hazard due to heating of the fuel from the environment around the tanks. In particular, the center tank may be located adjacent to the environmental control system that generates large amounts of heat. Various embodiments of the present disclosure reduce the flammability exposure of the fuel tank by insulating the tank from the hot compartment below and circulating colder fuel from the adjacent tanks.