Boundary Layer Sensor with Thin Thermocouple Wires
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Solution Overview
Problem
Existing boundary layer sensors are hindered by the presence of a flow body, which falsifies measurements and prevents the detection of rapid changes in flow dynamics, limiting their ability to accurately measure boundary layer thickness and flow profile.
Innovation Solution
A boundary layer sensor with at least three temperature-determining devices arranged at different distances from the surface, featuring thin wires with diameters of approximately 300 μm or less, which minimize heat capacity and flow interference, allowing for increased temporal resolution and accurate measurement of boundary layer thickness and flow profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flow body is used to mount temperature determination devices, then the devices are mechanically stable, but the flow body distorts the measurement and prevents detection of rapid flow changes
Solution Approach 1:
The patent extracts the temperature determination devices from the flow body mounting structure. Instead of mounting devices on a flow body, the devices are arranged directly in the flow at predetermined distances from the surface, eliminating the flow body's distorting influence while maintaining mechanical stability through direct flow-positioned arrangement.
2Productivity
If thin wires are used for temperature determination, then heat capacity is reduced and temporal resolution increases, but mechanical stability may be compromised
Solution Approach 1:
The patent changes the physical parameters of the temperature determination devices by using thin wires with diameters of approximately 300 μm or less. This parameter change reduces heat capacity and improves temporal resolution while the wires maintain sufficient mechanical stability through their structural design and arrangement in the flow.
3Measurement precision
If temperature determination devices are arranged at different distances from the surface, then boundary layer thickness can be determined, but device complexity increases
Solution Approach 1:
The patent segments the temperature determination into multiple discrete devices arranged at different predetermined distances from the surface. Each device measures temperature at its specific location, and the combination of these segmented measurements enables boundary layer thickness determination through profile analysis.
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 sensor effectively detects rapid temperature changes and maintains mechanical stability across a wide range of flow speeds, enabling precise measurement of boundary layer thickness and flow profile without deforming or impeding the flow, thus improving measurement accuracy and temporal resolution.
Implementation Method 1
at least two devices for determining a temperature each consist of a thermocouple, which has at least one wire made of a first material and at least one wire made of a second material, and a contact point connecting the first and the second wire
Data Source
Figure 1
AI summary
The invention relates to a boundary layer sensor (1) for determining the thickness of a boundary layer over a surface (65) of a body (6) around which a fluid flows, comprising a first device for determining a temperature (31), a second device for determining a temperature (32), and a third device for determining a temperature (33), each of which is arranged at a predefinable distance (X1, X2, X3) from the surface (65) of the body (6) around which a fluid flows, wherein at least the second and the third device for determining a temperature (32, 33) each consist of a thermocouple formed from a common first wire (21) made of a first material and at least one further wire (23, 24) made of a second material, each of which is connected to the first wire (21) at a contact point (12, 13), wherein the wires (21, 23,24) extend from the surface (65) into the hemisphere adjacent to the surface and have a diameter of approximately 300 µm or less. The invention further relates to a wind turbine, a vehicle, an aircraft, an indoor climate measuring device, or a ship with such a boundary layer sensor, and to a method for measuring the thickness of a boundary layer.