Fluid Handling Cavity Membrane for Ice Expansion Relief
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Solution Overview
Problem
Fluid handling assemblies, such as those in aircraft water systems, face damage due to ice buildup from trapped water, which expands and causes stress, as existing active heating systems are unreliable and inefficient for prolonged periods.
Innovation Solution
A passive method using a shape memory alloy membrane that changes shape to accommodate ice expansion, split into two sub-cavities, with a reversible transition at the freezing temperature of water, and optional thermal control features like heating wires and Peltier devices to manage ice formation and melting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If active heating systems (heating wires) are used to prevent ice formation, then ice buildup is prevented, but continuous electrical power is required and electrical noise interferes with other systems
Solution Approach 1:
The fluid handling assembly serves itself by accommodating ice expansion through the compliant membrane and air cavity system, eliminating the need for external heating systems. The assembly passively manages ice formation without requiring continuous power input or generating electrical noise.
Solution Approach 2:
Instead of preventing ice formation, the invention accepts ice as inevitable and converts the harmful expansion force into a beneficial passive mechanism. The air cavity and compliant membrane work together to absorb expansion pressure, transforming the harmful effect of ice expansion into a manageable design feature.
2Object-affected harmful factors
If active heating systems are used to prevent ice formation, then ice buildup is prevented, but the systems are unreliable and inefficient for prolonged periods
Solution Approach 1:
The passive accommodation system requires no external power source, control systems, or active components that could fail. The compliant membrane and air cavity system automatically respond to ice expansion without requiring maintenance, monitoring, or power supply, ensuring reliable operation during prolonged storage periods.
3Strength
If rigid cavity walls are used in fluid handling assemblies, then structural strength is maintained, but ice expansion causes harmful stress and damage
Solution Approach 1:
The invention replaces at least one rigid cavity wall with a compliant membrane that can deform elastically in response to ice expansion. This flexible membrane absorbs expansion forces through controlled deformation, preventing the harmful stress concentrations that would occur with rigid walls while maintaining the structural integrity of the overall assembly.
Solution Approach 2:
The cavity is divided into a first cavity (where ice forms) and a second cavity (air cushion zone), separated by the compliant membrane. This segmentation allows the ice-containing zone to expand independently into the air cushion zone without transmitting stress to the outer housing, while the housing maintains its rigid structural strength.
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
Effectively prevents stress on fluid handling assembly components by accommodating ice expansion without continuous power requirements, ensuring the assembly's integrity and reducing electrical interference.
Implementation Method 1
a shape memory alloy membrane that changes shape to accommodate ice expansion, split into two sub-cavities, with a reversible transition at the freezing temperature of water
Implementation Method 2
If the assembly encounters temperatures that fall to around or below the freezing point of water, then the water therein will turn to ice. It is a well-known phenomenon that the volume of the ice formed is greater than the volume of water it is formed from (the increase in volume being around 10%).
Data Source
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AI summary
The present disclosure provides a fluid handling assembly comprising a cavity (116) in which water may become trapped due to use of the assembly, and a membrane (120) disposed in the cavity (116). The membrane (120) divides the cavity (116) into a first sub-cavity (118a) on a first side of the membrane (120) that is configured to collect any water trapped in the cavity (116) and a second sub-cavity (118b) on a second, opposite side of the membrane (120). The membrane (120) is configured to change shape such that the first sub-cavity (118a) increases in volume and the second sub-cavity (118b) decreases in volume in response to being subjected to water freezing conditions. The increase in volume accommodates an increase in volume of any water that may be trapped in the first sub-cavity (118a) when it freezes to ice.