Optical Micro-Wire Flow-Velocity Sensor

Area of Science:

• Optoelectronics
• Sensor Technology
• Fluid Dynamics

Background:

• Accurate gas flow velocity measurement is crucial in various industrial and scientific applications.
• Existing sensors often face limitations in response time, cost, or complexity.
• Development of novel sensing mechanisms is needed to overcome these challenges.

Purpose of the Study:

• To present a novel, all-silica, gas-flow-velocity sensor with a short response time.
• To demonstrate a cost-efficient interrogation system using standard telecommunication components.
• To enable dynamic flow sensing, including turbulence detection.

Main Methods:

• Utilized a 16 µm diameter, optically absorbing micro-wire heated by a 980 nm light source.
• Formed a Fabry-Perot interferometer with the heated micro-wire, monitored at 1550 nm.
• Employed direct measurement of the sensor's thermal time constant for flow-velocity determination.

Main Results:

• Achieved a sensor bandwidth of approximately 22 Hz at low flow velocities.
• Demonstrated flow-velocity resolution up to 0.006 m/s using time constant measurement.
• Obtained a resolution better than 0.003 m/s in constant power configuration at low flow velocities.

Conclusions:

• The developed sensor offers a short response time and high resolution for gas flow velocity measurements.
• The system's reliance on standard telecommunication components ensures cost-efficiency and suitability for diverse applications.
• The sensor's capabilities extend to dynamic flow sensing and turbulence detection.