Fuel Tank Stringer Flow Passage Design
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Solution Overview
Problem
In aircraft fuel tanks, fuel can become trapped in stringer bays, preventing it from flowing to the low point where the fuel pump is located, and air can become trapped, hindering its release through the venting system.
Innovation Solution
A fuel tank design featuring a panel assembly with a stringer that includes a pair of portions connected by a bridge, where the bridge deviates away from the panel, allowing reinforcement fibers to extend between the portions and create a flow passage through a recess, enabling fluid to flow across the stringer and between bays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stringer is attached to the panel in a conventional manner, then structural strength is improved, but fuel and air flow are blocked in stringer bays
Solution Approach 1:
The stringer is segmented into two portions with a bridge connecting them, creating a recess between the bridge and panel. This segmentation allows the stringer to maintain structural strength while providing a flow passage through the recess, enabling fuel and air to flow across the stringer bay without complete blockage
Solution Approach 2:
The bridge acts as an intermediary element that connects the two portions of the stringer while creating a recess space. This intermediary structure allows fluid flow through the recess while maintaining the load-bearing function of the stringer, resolving the conflict between structural strength and flow reliability
2Ease of manufacture
If the bridge is positioned close to the panel, then manufacturing simplicity is improved, but flow passage capability is reduced
Solution Approach 1:
The bridge is positioned to create a recess with specific local geometry that optimizes flow passage capability in the critical area between the stringer and panel, while the overall stringer structure maintains conventional manufacturing simplicity. The local modification of creating a recessed area provides enhanced flow capability without requiring complete redesign of the entire stringer assembly
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 design ensures that fuel can flow under gravity from one stringer bay to another, reducing trapped fuel and allowing air to migrate to the vent system, thereby optimizing fuel distribution and tank filling efficiency.
Implementation Method 1
fuel can flow under gravity from one stringer bay to another
Implementation Method 2
allowing air to migrate to the vent system
Data Source
AI summary
A fuel tank is disclosed including a lower cover and an upper cover. The lower cover or the upper cover includes a panel assembly. The panel assembly includes a panel and a stringer attached to the panel. The stringer includes a pair of portions which are spaced apart in a lengthwise direction of the stringer and connected to each other by a bridge. Each portion is connected to a respective end of the bridge, and each end of the bridge deviates away from the panel. The stringer includes reinforcement fibres which extend between the portions via the bridge. Each reinforcement fibre deviates away from the panel at each end of the bridge. The stringer includes a stringer recess between the bridge and the panel, and a flow passage in the stringer recess through which fluid can flow across the stringer.