Ultrasonic waveguide for improved ultrasonic thermometry
Inventors
Cetiner, Nesrin O. • Cetiner, Mustafa S. • Roberts, Michael J. • Muth, Thomas R. • Varma, Venugopal K. • Montgomery, Rosemary A. • Muralidharan, Govindarajan
Assignees
UT Battelle LLC • University of Tennessee Research Foundation
Publication Number
US-12038333-B2
Publication Date
2024-07-16
Expiration Date
2040-08-21
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
An improved ultrasonic waveguide for an ultrasonic thermometry system is provided. The waveguide includes a series of sensing zones, each of which is tuned to a specific narrow frequency band. The waveguide is acoustically coupled to a transducer, which launches a longitudinal elastic wave of desired waveform and frequency. The wave propagates down the waveguide, and is reflected from the sensing zone that is tuned to that frequency. Each sensing zone is designed to be highly reflective to a narrow frequency band while being transparent to other frequencies.
Core Innovation
The invention provides an improved ultrasonic waveguide for ultrasonic thermometry systems, wherein the waveguide includes a sequence of sensing zones, each tuned to a specific narrow frequency band. Each sensing zone is designed with features that are highly reflective to its assigned frequency while being transparent to other frequencies. The waveguide is acoustically coupled to a transducer that launches a longitudinal elastic wave; as the wave travels through the waveguide, it is selectively reflected by the sensing zone matched to its frequency, allowing for localized measurement.
Traditionally, ultrasonic thermometry systems have faced significant limitations: prior waveguides employ geometrically identical notches without frequency specificity, resulting in cumulative energy loss at each sensing zone and poor signal-to-noise ratios, particularly for distant zones. This degrades the accuracy and reliability of temperature measurement in harsh environments, such as advanced nuclear reactors, where conventional sensors like RTDs or thermocouples suffer from insulation breakdown at high temperatures.
The present invention addresses these shortcomings by using sensing zones with periodic structures—formed either by fused alternating materials or by varying cross-sectional area—engineered to function as narrow-band notch filters. Each sensing zone consists of reflection features separated by a known distance, optimized for constructive interference at the specific interrogation frequency. This permits individual interrogation of each zone by its designated frequency, maximizing local reflectance and minimizing overall signal attenuation, thereby enabling distributed, accurate, and robust temperature sensing along a single waveguide.
Claims Coverage
The patent includes one independent claim identifying several inventive features related to an ultrasonic temperature sensing method using a specially structured waveguide.
Ultrasonic waveguide with frequency-specific band-rejection sensing zones
The method claims an ultrasonic waveguide with multiple axially-distributed sensing zones, each comprising first and second reflection features that define a band-rejection response tuned to a particular interrogation frequency. - The proximal sensing zone reflects a first ultrasonic signal of a first frequency and is substantially transmissive to a second signal, while the distal sensing zone reflects a second ultrasonic signal of a different frequency. - Each zone's reflection features are arranged so two time-delayed copies of the specific frequency return to the proximal end for analysis.
Localized temperature determination based on time-of-flight of reflected frequency-specific signals
The method determines temperature within each sensing zone by: 1. Launching targeted ultrasonic signals at the proximal end, 2. Receiving two time-delayed reflected copies from within each corresponding sensing zone, and 3. Analyzing these reflections—specifically the time-of-flight difference between them—at the proximal end to infer the local temperature in the waveguide.
Together, these features establish a distributed temperature sensing approach based on an ultrasonic waveguide with frequency-selective, narrowly-tuned, spatially localized reflection features for reliable and accurate thermometry in challenging environments.
Stated Advantages
Provides reliable, highly accurate temperature measurements at multiple locations using a single waveguide, reducing the number of instrument penetrations and minimizing obstructions in fluid flow paths.
Minimizes signal attenuation in the waveguide while maximizing the response at each temperature sensing zone, improving sensitivity in high-temperature and harsh environments.
Enables measurement in environments (such as nuclear reactor cores) where conventional sensors rapidly lose calibration or fail due to insulation breakdown at high temperatures.
Documented Applications
Temperature measurement at multiple locations in nuclear reactor cores using a single ultrasonic waveguide.
Distributed temperature sensing for high-temperature and potentially harsh industrial applications.
Modification of components in nuclear reactor or industrial process systems to incorporate spatially distributed temperature sensing based on the described waveguide.
Interested in licensing this patent?