Insulated Aircraft Motive Flow Line for Ice Prevention
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Solution Overview
Problem
Aircraft motive flow lines are prone to ice accumulation due to temperature drops, leading to blockages, especially when the distance between the engine and injection point results in motive flow temperature dropping below freezing, affecting fuel flow rates under various in-flight conditions.
Innovation Solution
An aircraft motive flow line comprising an outer tube made of high-strength material and an inner tube with lower thermal conductivity, positioned to create a gap for thermal insulation, with a port connecting the inner tube to the gap to regulate flow and prevent icing, while also providing mechanical protection and pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the distance between the engine and injection point is increased, then the fuel transfer capability is improved, but the motive flow temperature drops below freezing causing ice accumulation
Solution Approach 1:
The patent introduces thermal insulation material as an intermediary between the motive flow and the external environment. This mediator prevents heat transfer from the surrounding air to the cold motive flow, allowing the system to maintain extended reach without the temperature dropping to freezing levels.
Solution Approach 2:
The patent changes the thermal parameters of the flow line system by implementing thermal insulation. This modifies the heat transfer characteristics, reducing the rate of heat gain from the environment and maintaining the motive flow temperature above freezing throughout the extended line length.
2Reliability
If thermal insulation is added to prevent ice accumulation, then the temperature is maintained, but the device complexity increases
Solution Approach 1:
The patent implements thermal insulation by nesting it within the existing flow line structure. The insulation is placed inside the outer housing or between internal components, utilizing the existing structural envelope rather than adding external attachments, thus minimizing structural complexity.
Solution Approach 2:
The patent employs flexible thermal insulation materials that can be integrated into the flow line structure. These thin-film or flexible insulation layers conform to the existing geometry, requiring minimal structural modification while providing effective thermal protection.
3Strength
If a single high-strength material is used for the flow line, then the mechanical strength is sufficient, but the thermal conductivity is high causing temperature loss
Solution Approach 1:
The patent employs a composite structure combining materials with different properties. The outer structure uses high-strength material for mechanical integrity, while the inner layer or surrounding material uses low thermal conductivity substance for thermal insulation, achieving both strength and temperature maintenance.
Solution Approach 2:
The patent segments the flow line into functional zones: an inner core for fluid transport, an intermediate insulation layer for thermal protection, and an outer structural layer for mechanical strength. This segmentation allows each layer to be optimized for its specific function without compromising the others.
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 solution effectively prevents ice accumulation by maintaining a higher temperature within the inner tube, enhancing fuel flow rates and reducing the risk of blockages, thus improving the reliability and efficiency of fuel transfer in aircraft systems.
Implementation Method 1
an inner tube extending longitudinally inside the outer tube, the inner tube being made out of a second material having a thermal conductivity coefficient lower than that of the first material
Implementation Method 2
the inner tube being sized and held in position relative to the outer tube so as to define a gap between an exterior of the inner tube and an interior of the outer tube
Data Source
AI summary
An aircraft motive flow line includes an outer tube made out of a first material and an inner tube extending longitudinally inside the outer tube. The inner tube is made out of a second material having a thermal conductivity coefficient lower than that of the first material. The first material has a strength coefficient greater than that of the second material. The inner tube is sized and held in position relative to the outer tube so as to define a gap between an exterior of the inner tube and an interior of the outer tube. A port fluidly connects an interior of the inner tube to the gap.