Improved Acoustic Thermometry for Long-Distance Temperature Measurements

Accurate measurements of long distances (in the order of tens of meters or more) are necessary in manufacturing processes of large structures, as, for example, in the aerospace industry. In the most demanding applications, the goal is to achieve a relative accuracy of 10<sup>−7</sup> in...

Full description

Bibliographic Details
Main Authors: Marco Pisani, Milena Astrua, Massimo Zucco
Format: Article
Language:English
Published: MDPI AG 2023-02-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/23/3/1638
_version_ 1827759333620842496
author Marco Pisani
Milena Astrua
Massimo Zucco
author_facet Marco Pisani
Milena Astrua
Massimo Zucco
author_sort Marco Pisani
collection DOAJ
description Accurate measurements of long distances (in the order of tens of meters or more) are necessary in manufacturing processes of large structures, as, for example, in the aerospace industry. In the most demanding applications, the goal is to achieve a relative accuracy of 10<sup>−7</sup> in the measurement of distances (e.g., 1 µm over 10 m). This goal can be obtained with laser interferometers whose accuracy is based on knowledge of the speed of light, which, in turn, depends on the temperature of air. A thermometer based on the measurement of the speed of sound in air has been realized at INRIM. Its purpose is the measurement of the air temperature along the measurement path of the interferometer with an accuracy of 0.1 °C at distances up to 11 m. The paper describes the principle and the experimental setup of the acoustic thermometer and demonstrates its performance by comparison with calibrated reference platinum resistance thermometers. Furthermore, we demonstrate the potentiality of the method to measure the vertical temperature gradient, which is the main error source in triangulation measurements when using laser trackers.
first_indexed 2024-03-11T09:24:50Z
format Article
id doaj.art-1ffbed2a764b4f0fbd19990102116aa5
institution Directory Open Access Journal
issn 1424-8220
language English
last_indexed 2024-03-11T09:24:50Z
publishDate 2023-02-01
publisher MDPI AG
record_format Article
series Sensors
spelling doaj.art-1ffbed2a764b4f0fbd19990102116aa52023-11-16T18:04:00ZengMDPI AGSensors1424-82202023-02-01233163810.3390/s23031638Improved Acoustic Thermometry for Long-Distance Temperature MeasurementsMarco Pisani0Milena Astrua1Massimo Zucco2Istituto Nazionale di Ricerca Metrologica, INRIM, 10135 Torino, ItalyIstituto Nazionale di Ricerca Metrologica, INRIM, 10135 Torino, ItalyIstituto Nazionale di Ricerca Metrologica, INRIM, 10135 Torino, ItalyAccurate measurements of long distances (in the order of tens of meters or more) are necessary in manufacturing processes of large structures, as, for example, in the aerospace industry. In the most demanding applications, the goal is to achieve a relative accuracy of 10<sup>−7</sup> in the measurement of distances (e.g., 1 µm over 10 m). This goal can be obtained with laser interferometers whose accuracy is based on knowledge of the speed of light, which, in turn, depends on the temperature of air. A thermometer based on the measurement of the speed of sound in air has been realized at INRIM. Its purpose is the measurement of the air temperature along the measurement path of the interferometer with an accuracy of 0.1 °C at distances up to 11 m. The paper describes the principle and the experimental setup of the acoustic thermometer and demonstrates its performance by comparison with calibrated reference platinum resistance thermometers. Furthermore, we demonstrate the potentiality of the method to measure the vertical temperature gradient, which is the main error source in triangulation measurements when using laser trackers.https://www.mdpi.com/1424-8220/23/3/1638long-distance measurementsinterferometrythermometryspeed of soundaerospace manufacturinglaser trackers
spellingShingle Marco Pisani
Milena Astrua
Massimo Zucco
Improved Acoustic Thermometry for Long-Distance Temperature Measurements
Sensors
long-distance measurements
interferometry
thermometry
speed of sound
aerospace manufacturing
laser trackers
title Improved Acoustic Thermometry for Long-Distance Temperature Measurements
title_full Improved Acoustic Thermometry for Long-Distance Temperature Measurements
title_fullStr Improved Acoustic Thermometry for Long-Distance Temperature Measurements
title_full_unstemmed Improved Acoustic Thermometry for Long-Distance Temperature Measurements
title_short Improved Acoustic Thermometry for Long-Distance Temperature Measurements
title_sort improved acoustic thermometry for long distance temperature measurements
topic long-distance measurements
interferometry
thermometry
speed of sound
aerospace manufacturing
laser trackers
url https://www.mdpi.com/1424-8220/23/3/1638
work_keys_str_mv AT marcopisani improvedacousticthermometryforlongdistancetemperaturemeasurements
AT milenaastrua improvedacousticthermometryforlongdistancetemperaturemeasurements
AT massimozucco improvedacousticthermometryforlongdistancetemperaturemeasurements