Pitot Probe Dams for Icing Protection
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Solution Overview
Problem
Pitot tubes in aircraft data management systems face issues with ice buildup due to ingested ice crystals and water droplets, leading to inaccurate airspeed measurements, especially in varying orientations and installations, which fail to meet stringent icing regulations.
Innovation Solution
The design incorporates at least three dams strategically positioned within the pitot probe, with a heater element integrated outside the dams, allowing for effective blocking, melting, and drainage of ice crystals and water droplets, ensuring reliable pressure measurements across multiple orientations and installations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two dams are used to block water droplets and ice crystals, then the probe can prevent ice buildup in some orientations, but the same design fails to meet icing regulations in other orientations and installations
Solution Approach 1:
The internal flow passage is divided into multiple segments by adding at least one additional dam between the first and second dams. This segmentation creates multiple blocking points that work together to prevent ice crystals and water droplets from reaching the total pressure sensing element regardless of probe orientation. The segmented approach ensures that ice accumulation is blocked at multiple locations rather than relying on a single dam configuration.
Solution Approach 2:
The probe design achieves universality by configuring multiple dams and heating elements to perform the same ice prevention function across all possible installation orientations. The symmetric arrangement of dams and heating elements ensures that the probe meets icing regulations whether installed on the left or right side of the aircraft, eliminating the need for orientation-specific designs.
2Temperature
If heating elements are placed inside the probe, then ice can be melted, but the heater capacity is overwhelmed by large amounts of ingested ice crystals and super cooled water droplets
Solution Approach 1:
Heating elements are positioned to apply heat to the dam structures before ice crystals and water droplets can accumulate and block the flow passage. This preliminary heating action prevents ice from forming on the dams and maintains open drainage paths, reducing the overall ice load that the heating system must handle.
Solution Approach 2:
The dams serve as intermediary structures that concentrate and control the flow of ice crystals and water droplets to designated drainage openings. By directing ice-laden flow to specific drain locations, the heating elements can more effectively melt and clear ice at these concentrated points rather than attempting to heat the entire flow passage uniformly.
3Ease of operation
If melted ice is allowed to flow past the heated region, then drainage occurs, but the ice can refreeze in cooler regions deep inside the probe and block pressure measurement
Solution Approach 1:
Heating elements are positioned to provide continuous thermal protection along the flow path past the dams, ensuring that melted ice and water remain in liquid form as they drain through the probe. This continuous heating action prevents refreezing in downstream cooler regions and maintains unobstructed flow paths to the drainage openings, ensuring reliable pressure measurements.
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 configuration provides enhanced icing protection, ensuring accurate airspeed measurements by preventing ice buildup and meeting stringent icing requirements, regardless of the probe's orientation or installation, thus maintaining the reliability of air data probes.
Implementation Method 1
a heater element integrated into the tube of the pitot probe on the outside of the dams
Implementation Method 2
The at least three dams are oriented within the tube of the pitot probe in such a way that the dam locations are configured for two or more installations of the air data probe
Implementation Method 3
The dams in the Pitot probe block the water droplets and ice crystals from traveling deep into the probe and direct them to flow out through small drain holes in the pitot tube
Data Source
AI summary
An air data probe is provided. The air data probe includes a pitot probe having a mounting base or flange, support strut, and tube with a forward facing inlet that is configured to capture a total pressure of the surrounding air, at least three dams placed within the tube of the pitot probe for blocking the ballistic trajectory of water droplets or ice crystals from passing directly through the tube to a downstream pressure sensing element, and a heater element integrated into the tube of the pitot probe on the outside of the dams. The at least three dams are oriented within the tube of the pitot probe in such a way that the dam locations are configured for two or more installations of the air data probe.