Nonlinear damping in optical fiber anemometry
US20250355016A1
Abstract
A flow sensing system including a light source and a light sensor; an optical fiber including a fiber core exposed at a face of the optical fiber; an anemometer for measuring a fluid flow, the anemometer including: a stator; a rotor including one or more blades having a reflective surface for reflecting light from the fiber core back into the fiber core for measurement by the light sensor; and a gap between the stator and the rotor. The anemometer is positioned at the face of the optical fiber such that, as the rotor rotates, the blades of the rotor pass the fiber core reflecting light from the light source back into the fiber core, the fiber core receives the light reflected by the reflective surface and transmits it to the light sensor, and a stabilizing agent is filled in the gap between the stator and the rotor.
Description (excerpt)
CROSS-REFERENCE TO RELATED APPLICATIONS Pursuant to 37 C.F.R. § 1.78(a)(4), this application claims the benefit of and priority to prior filed co-pending Provisional Application Ser. No. 63/648,396, filed May 16, 2024, which is expressly incorporated herein by reference in its entirety. This application is also related to U.S. Pat. No. 11,635,315, entitled, “Optical Fiber Tip Anemometer” and incorporates this reference in its entirety. RIGHTS OF THE GOVERNMENT The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty. FIELD OF THE INVENTION The present invention relates generally to microscopic sensors and, more particularly, to microscopic passive optical sensors fabricated on a tip of an optical fiber and methods of fabricating same. BACKGROUND OF THE INVENTION Accurate measurement of fluid flow rates is crucial in various applications, ranging from industrial processes to environmental monitoring. Traditional methods for fluid flow measurement often rely on anemometers, which are designed to detect the speed and direction of fluid flow. However, most conventional anemometers suffer from significant limitations, particularly in providing consistent periodic responses during measurements. These inconsistencies can arise from factors such as mechanical wear, environmental disturbances, or dynamic changes in the fluid's properties, leading to fluctuating or unreliable readings. They can also be introduced do to insufficient design. Current anemometers, including those based on mechanical and optical principles, often fail to maintain a stable and predictable periodic response throughout extended use or under varying fluid conditions because of mechanical forces (e.g., friction) developed based on movement of parts of the anemometers. As a result, flow measurements may be prone to errors, reducing the accuracy and reliability required for critical applications. Furthermore, without a consistent response, real-time monitoring and precise control of fluid systems become challenging, potentially compromising performance and system stability. Accordingly, systems that display an ability to measure flow with a consistent periodic response may be required. SUMMARY OF THE INVENTION The present invention overcomes the foregoing problems and other shortcomings, drawbacks, and challenges of current flow sensing systems. While the invention will be described in connection with certain embodiments, it will be understood that the invention is not limited to these embodiments. To the contrary, this invention includes all alternatives, modifications, and equivalents as may be included within the spirit and scope of the present invention. According to one embodiment of the present invention a fluid flow sensing system includes a light source and a light sensor; an optical fiber including a fiber core exposed at a face of the optical fiber such that light from the light source can pass out of and into the fiber core; an anemometer for measuring a fluid flow, the anemometer including: a stator; a rotor including one or more blades having a reflective surface for reflecting light from the fiber core back into the fiber core for measurement by the light sensor; and a gap between the stator and the rotor. The anemometer is positioned at the face of the optical fiber such that, as the rotor rotates, the blades of the rotor pass the fiber core reflecting light from the light source back into the fiber core, the fiber core receives the light reflected by the reflective surface and transmits it to the light sensor, and a stabilizing agent is filled in the gap between the stator and the rotor. According to another embodiment, an anemometer for measuring a fluid flow includes a stator; a rotor including one or more blades having a reflective surface for reflecting light from a fiber core back into the fiber core for measurement by a light sensor; and a gap between the stator and the rotor, wherein a stabilizing agent is filled in the gap between the stator and the rotor. According to yet another embodiment, a flow sensing system includes a light source; a light sensor; and a micro, optomechanical anemometer including an optical fiber including a fiber core exposed at a face of the optical fiber such that light from the light source can pass out of and into the fiber core; a stator; a rotor including one or more blades having a reflective surface for reflecting light from the fiber core back into the fiber core for measurement by the light sensor; and a gap between the stator and the rotor. The micro, optomechanical anemometer is positioned at the face of the optical fiber such that, as the rotor rotates, the blades of the rotor pass the fiber core reflect
Filing details
- Inventors
- Hengky CHANDRAHALIM
- Assignee
- Government Of The United States As Represented By The Secretary Of The Air …
- Filed
- Mar 27, 2025
- Granted
- Application pending
Bibliographic data and excerpted text sourced from Google Patents (public record) as part of IP TechMatch's current-filings monitor. This filing is not part of the 2019 historical archive. For the authoritative full text, drawings, and legal status, see the source links above or consult USPTO records directly.