Phase Change Cell Capillary Gas Pocket Isolation
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Solution Overview
Problem
Existing phase change cells in micro-gravity environments face inaccuracies in temperature measurement due to uncontrolled gas pockets adjacent to temperature sensors, and require complex structures for measuring multiple phase change temperatures.
Innovation Solution
A phase change cell design featuring capillaries along the chamber walls to draw the phase change material towards the periphery, preventing gas pockets from interfering with temperature sensors, and a moveable surface to control pressure and achieve multiple phase change temperatures using a single chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas pocket is present in the phase change chamber, then the chamber can accommodate phase change material volume changes, but the gas pocket may be adjacent to the temperature sensor and cause inaccurate temperature measurements
Solution Approach 1:
The temperature sensor is extracted from the phase change chamber environment and placed in thermal communication with the phase change material through a thermal conductor, isolating it from direct contact with gas pockets while maintaining accurate temperature measurement of the phase change material
Solution Approach 2:
A thermal conductor acts as an intermediary between the temperature sensor and the phase change material, allowing thermal energy transfer while physically separating the sensor from gas pockets that would otherwise cause measurement errors
2Adaptability or versatility
If multiple chambers are used to house different phase change materials for curve fitting calibration, then multiple phase change temperatures can be measured, but the device complexity increases
Solution Approach 1:
A single phase change chamber is designed to accommodate multiple different phase change materials, allowing the same chamber structure to serve multiple calibration purposes by simply replacing the phase change material rather than requiring separate chambers for each material
Solution Approach 2:
The functions of multiple chambers housing different phase change materials are merged into a single chamber that can hold one phase change material at a time, combining what would have been separate physical units into one versatile device
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
Ensures accurate temperature measurement by isolating the phase change material from gas pockets and allows for multiple phase change temperature readings without the need for multiple chambers or materials.
Implementation Method 1
A capillary is disposed along a periphery of the phase change chamber and comprises a channel formed in an interior surface of the side wall. In response to heating of the phase change cell, the capillary is configured to draw the phase change material in a liquid phase towards the periphery of the phase change chamber.
Implementation Method 2
A phase change material occupies a majority of a volume of the phase change chamber and is configured to change between a solid phase and a liquid phase at a phase change temperature in response to heating or cooling
Implementation Method 3
At this point, the phase change material will continue to absorb a significant amount of heat at a virtually constant temperature until all the material is transformed to the liquid phase. Likewise, the phase change material will release its stored latent heat energy at its phase change temperature in the transition from a liquid phase to a solid phase.
Data Source
AI summary
A phase change cell includes a housing enclosing a phase change chamber that holds a phase change material and a gas pocket. The housing includes a side wall extending between first and second end walls. A capillary is disposed in an interior surface of the side wall. In response to heating of the phase change cell, the capillary is configured to draw the phase change material in a liquid phase towards the periphery of the phase change chamber. A temperature sensor is coupled to the housing in a vicinity of the capillary to measure the phase change temperature. According to another aspect, the housing includes a moveable surface that bounds a portion of the phase change chamber. The phase change temperature of the phase change material changes based on the position of the moveable wall.