Self-Heated Cloud Water Sensor for SLD Detection
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Solution Overview
Problem
Current aircraft icing sensors are inadequate in measuring water droplet size and rejecting unwanted ice crystals, leading to inaccurate liquid water content measurements and a lack of protection against severe icing conditions, particularly supercooled large droplets (SLD), which pose significant safety risks.
Innovation Solution
A system comprising co-located, self-heated sensors with temperature-controlled resistance characteristics, a compensation sensor, and a control unit to differentiate between heat loss due to liquid water and ice water, providing improved rejection of ice crystals and accurate measurement of droplet size and liquid water content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external heater windings are used to heat the sensor, then the sensor can be heated, but the windings create small pockets that trap ice crystals causing false measurements and have a very short life
Solution Approach 1:
The patent removes the external heater windings from the sensor design entirely. Instead, it uses an internal heating element that is integrated into the sensor body, eliminating the pockets that trapped ice crystals and caused false measurements. This extraction of the problematic external winding component directly resolves the reliability issue while maintaining heating capability.
Solution Approach 2:
The sensor uses its own internal heating element to heat itself, rather than relying on external windings. The internal heater is designed to heat the sensor body uniformly without creating trapping pockets, and the sensor automatically cycles the heater on and off based on temperature feedback, making the system self-regulating and more reliable.
2Measurement precision
If internal switched indirectly heated cylindrical element is used to collect super cooled liquid water, then the sensor can measure liquid water content, but the element freezes onto the cylinder and requires complex heating cycles to clear ice
Solution Approach 1:
The sensor uses its own internal heating element to heat itself, rather than relying on external windings. The internal heater is designed to heat the sensor body uniformly without creating trapping pockets, and the sensor automatically cycles the heater on and off based on temperature feedback, making the system self-regulating and more reliable.
Solution Approach 2:
The patent changes the heating approach by using an internal heating element that can be directly controlled. Instead of complex switched indirect heating cycles, the internal heater can be controlled more simply through temperature feedback, reducing the complexity of the control system while maintaining the ability to clear ice from the sensor surface.
3Device complexity
If simple LWC sensors are used, then the device is simple, but they cannot reject unwanted ice crystals and provide inaccurate measurements
Solution Approach 1:
The patent applies different surface treatments to different parts of the sensor. The sensing surface is made hydrophobic to repel water and ice crystals, while other parts of the sensor have different surface properties. This local differentiation allows the sensor to reject ice crystals accurately while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent uses surface treatment changes rather than color changes. The sensing surface is treated with a hydrophobic coating that changes the surface energy and wetting properties, allowing it to repel water and ice crystals. This surface property change enables the simple sensor structure to achieve high measurement precision by rejecting unwanted ice crystals.
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 system achieves a better than tenfold improvement in rejecting unwanted ice crystals and provides accurate measurements of liquid water content and droplet size, enhancing aircraft safety by effectively detecting SLD conditions.
Implementation Method 1
heat loss from the sensors due to evaporation of liquid water and/or melting of ice water
Implementation Method 2
heat loss from the sensors due to evaporation of liquid water and/or melting of ice water
Implementation Method 3
temperature-dependent resistance characteristics
Data Source
AI summary
A system and method for providing a statistical measure of the size of liquid water droplets in a cloud, as well as a system and method for the detection and/or measurement of the presence of a cloud, liquid water content in the cloud and ice water content in the cloud, among other parameters.