Dual-Sensor Cloud Ice Detection via Power Differential
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Solution Overview
Problem
Existing cloud ice sensors require separate compensation sensors to account for cooling effects of dry air, which is inefficient and not always necessary, and do not effectively detect threshold amounts of ice crystals without additional sensors.
Innovation Solution
The system employs two self-heated, semi-cylinder shaped sensors mounted in a leading edge of an airfoil, oriented differently to distinguish between liquid water and ice crystals based on heat loss differences, eliminating the need for separate compensation sensors and providing a direct measure of ice crystal presence using power thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate compensation sensors are used to account for dry air cooling effects, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines the functions of detecting liquid water content, ice crystal content, and compensating for dry air cooling effects into a single sensor element. By integrating multiple measurement capabilities into one device, the system eliminates the need for separate compensation sensors while maintaining measurement accuracy through computational differentiation of the combined signals.
2Measurement precision
If multiple sensors are used to detect both liquid water and ice crystals separately, then measurement precision is improved, but the number of components increases
Solution Approach 1:
The sensor element is designed to perform multiple functions simultaneously: detecting liquid water content, detecting ice crystal content, and providing data for dry air cooling compensation. This multi-functional approach allows a single sensor to replace what would traditionally require multiple separate sensors, reducing system complexity while maintaining detection accuracy.
Solution Approach 2:
The system detects different types of precipitation by measuring changes in electrical parameters (conductivity, capacitance) that vary depending on whether liquid water or ice crystals are present. By analyzing these parameter changes rather than using physically separate sensors, the system can distinguish between different precipitation types with a single sensor element.
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 approach allows for robust detection of ice crystals without additional sensors, improving aircraft safety by accurately measuring ice crystal content and providing timely warnings, even at higher airspeeds where ice ingestion is a greater concern.
Implementation Method 1
Water 'retained' by the sensor is continuously evaporated by a portion of the applied power. The total power used to evaporate the liquid water, after corrections for cooling from moving air alone, can provide a measure of liquid water content.
Implementation Method 2
The retained ice crystals (after being converted to water) and the liquid water 'retained' by the sensor are both continuously evaporated by the applied power. The total power used to evaporate the net liquid water, after corrections for cooling from moving air alone, gives a measure of the total water content.
Data Source
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AI summary
A system for detecting the presence of ice crystals in a cloud comprising two thin walled semicylinder-shaped sensors, one having a concave inner surface and oriented longitudinally in a leading edge of an airfoil and the other having a convex outer surface being oriented longitudinally in the leading edge of the airfoil so that cloud water flows towards and into contact with the convex outer surface; a temperature controlling arrangement for heating the two sensors and maintaining them at a substantially constant temperature; and a comparison arrangement for finding a difference between (i) a power to maintain the temperature of the first sensor at its substantially constant temperature (ii) a power to maintain the temperature of the second sensor at its substantially constant temperature; and comparing the difference of the powers to a threshold value for evidencing the presence or predetermined amount of ice in the cloud water.