Air Data Probe Raised Port Trips Boundary Layer
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Solution Overview
Problem
Air data probes experience inconsistent measurement errors at high altitudes and/or high Mach numbers due to sensitivity to unknown variables, leading to variations in static pressure readings.
Innovation Solution
The air data probe incorporates a raised portion on its surface, configured to trip the fluid boundary layer from laminar to turbulent flow, reducing boundary layer separation and ensuring consistent readings by transitioning the flow at low Reynolds numbers, high altitudes, and angles of attack. This raised portion can be arranged in various geometric patterns and shapes, including strips, zig-zag patterns, and discrete elements, with sharp or curved transitions, and is applied using techniques like brazing or additive manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional air data probe design is used, then the probe can operate at high altitudes and Mach numbers, but measurement consistency deteriorates due to boundary layer separation and sensitivity to unknown variables
Solution Approach 1:
The raised portion is positioned upstream of the static pressure ports to trip the boundary layer transition from laminar to turbulent flow before the flow reaches the measurement ports. This preliminary action ensures that the boundary layer is already turbulent when it passes over the static ports, preventing separation and ensuring consistent measurements at high altitudes and Mach numbers
Solution Approach 2:
The raised portion changes the flow regime parameter by forcing transition from laminar to turbulent boundary layer. This parameter change in the boundary layer state eliminates the sensitivity to unknown variables and ensures consistent static pressure measurements across different flight conditions including high altitude and Mach number operations
2Reliability
If the raised portion is added to trip the boundary layer, then measurement consistency improves, but device complexity increases
Solution Approach 1:
Rather than modifying the entire probe structure, the invention applies a localized raised portion only at specific locations on the probe head surface where boundary layer transition is needed. This localized modification achieves the desired flow control while minimizing overall device complexity
Solution Approach 2:
The raised portion can be implemented as discrete segmented elements rather than a continuous structure. This segmentation allows for easier manufacturing and integration while achieving the same boundary layer tripping effect, thereby reducing device complexity
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 solution effectively reduces boundary layer separation, resulting in consistent and accurate measurements across a range of flight conditions, enhancing the reliability of air data probes at high altitudes and Mach numbers.
Implementation Method 1
The raised portion is configured and adapted to trip a fluid boundary layer passing over the probe head to transition from laminar to turbulent for reducing boundary layer separation
Implementation Method 2
trip a fluid boundary layer passing over the probe head to transition from laminar to turbulent for reducing boundary layer separation
Data Source
AI summary
An air data probe includes a probe head and a raised portion. The probe head defines a longitudinal axis and includes a forward tip and a probe head surface. The raised portion is defined in the probe head surface aft of the forward tip. The raised portion is raised radially relative to the probe head surface. The raised portion is configured and adapted to trip a fluid boundary layer passing over the probe head to transition from laminar to turbulent for reducing boundary layer separation for consistent readings at high altitudes and/or high mach numbers. A method of manufacturing an air data probe includes forming a probe head and applying a raised portion to a surface of the probe head aft of the forward tip. Applying the raised portion to the surface of the probe head includes using brazing, additive manufacturing, adhesives and/or any other suitable technique.