Self-orienting Heated Element Sensor for Turbulent Flux Measurement
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Solution Overview
Problem
Existing fluid flux measurement systems, particularly atmospheric boundary layer anemometers, are inadequate for remotely measuring atmospheric turbulence across a wide range of turbulent structures and mean wind directions due to limitations in sonic anemometers' sampling frequency and heated element sensors' fragility and calibration needs.
Innovation Solution
A self-orienting and self-calibrating fluid flux measurement system that mounts a heated element fluid flow sensor on a movable member, allowing it to automatically adjust its direction to align with the mean wind direction, and integrates a sonic anemometer for calibration and protection, enabling robust and accurate measurements of small-scale turbulence over a wide range of angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a heated element fluid flow sensor is used to measure small-scale turbulence, then measurement precision is improved, but reliability deteriorates due to fragility and calibration needs
Solution Approach 1:
The patent combines a heated element fluid flow sensor (for high-precision small-scale turbulence measurement) with a sonic anemometer (for robust wide-angle measurement) into a single integrated system. The heated element sensor provides superior measurement precision for small-scale turbulence, while the sonic anemometer compensates for reliability issues by providing backup measurement capability and calibration reference, thus resolving the contradiction between precision and reliability
Solution Approach 2:
The sonic anemometer serves as an intermediary that protects the heated element sensor system. It provides a robust measurement capability that can operate independently when the heated element sensor is compromised, and serves as a calibration reference to maintain measurement accuracy, thereby enhancing overall system reliability without sacrificing the precision benefits of the heated element sensor
2Adaptability or versatility
If a sonic anemometer is used for wide-range wind direction measurement, then adaptability is improved, but measurement precision deteriorates due to low sampling frequency
Solution Approach 1:
The system merges a sonic anemometer (providing wide 360-degree wind direction measurement capability) with a heated element fluid flow sensor (providing high-frequency small-scale turbulence measurement). The sonic anemometer's ultrasonic transducers measure wind speed and direction across all directions, while the heated element sensor captures high-frequency turbulence data, together resolving the contradiction between wide adaptability and measurement precision
Solution Approach 2:
The patent implements a movable mounting structure that dynamically repositions the heated element sensor to maintain optimal alignment with the mean wind direction. This dynamic adjustment allows the heated element sensor (which has limited angular acceptance) to consistently operate at its optimal measurement angle while the sonic anemometer continues to provide wide-range wind direction data, thus maintaining both adaptability and precision
3Measurement precision
If a heated element sensor is mounted on a movable member to maintain alignment, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent employs a movable mounting structure with an actuator that dynamically adjusts the orientation of the heated element sensor based on real-time wind direction measurements from the sonic anemometer. This dynamic repositioning maintains optimal sensor-to-wind alignment, ensuring high measurement precision while the added mechanical complexity is justified by the significant improvement in measurement accuracy across varying wind conditions
4Adaptability or versatility
If sonic anemometer transducers are positioned far apart, then measurement of large-scale features is improved, but measurement of small-scale turbulence deteriorates
Solution Approach 1:
The system combines a sonic anemometer with widely spaced transducers (capable of measuring large-scale turbulent features) with a heated element fluid flow sensor (capable of measuring small-scale turbulence). The heated element sensor's small sensing volume allows it to resolve fine-scale turbulent structures that would be averaged out by the larger spacing of the sonic anemometer transducers, while the sonic anemometer provides complementary large-scale measurement capability, thus achieving measurement across the full range of turbulent scales
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 effectively measures momentum flux and small-scale turbulent fluxes, improving numerical weather prediction, climate simulation, and air pollution calculations by combining the high-frequency capabilities of heated element sensors with the durability and wide-angle measurement of sonic anemometers.
Implementation Method 1
Heated element fluid flow sensors may be used to measure fluid velocity based on the amount of heat transported away by a fluid passing a heated element. The amount of heat lost is a function of the fluid velocity passing the element.
Implementation Method 2
The sonic anemometers employ a plurality of ultrasonic transducers to generate and receive ultrasonic signals. Signal propagation times along linear paths between transducers are determined and used to calculate wind speed and direction.
Data Source
AI summary
A fluid flux measurement system that includes a heated element fluid flow sensor that is capable of being repositioned relative to a mean fluid flux direction is disclosed. The repositioning may be performed by a motor interconnected to the heated element fluid flow sensor. The heated element fluid flow sensor may be positioned proximate to the measurement region of a sonic anemometer and may be operable to be repositioned relative to the sonic anemometer. The heated element fluid flow sensor may be a three-dimensional hot-film constant temperature anemometer. The fluid flux system may be operable to measure small-scale turbulent fluxes in uncontrolled environments such as remotely located atmospheric monitoring stations. The heated element fluid flow sensor may be calibrated in-situ with data collected by the sonic anemometer.