Spectroscopic techniques versus Pitot tube for the measurement of flow velocity in narrow ducts

Year: 2020

Authors: D’Amato F., Viciani S., Montori A., Barucci M., Morreale C., Bertagna S., Migliavacca G.

Autors Affiliation: CNR-INO, Area CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy; Innovhub Stazioni Sperimentali per l’Industria srl, Via G. Galilei 1, 20097 San Donato Milanese, Italy.

Abstract: In order to assess the limits and applicability of Pitot tubes for the measurement of flow velocity in narrow ducts, e.g., biomass burning plants, an optical, dual function device was implemented. This sensor, based on spectroscopic techniques, targets a trace gas, injected inside the stack either in bursts, or continuously, so performing transit time or dilution measurements. A comparison of the two optical techniques with respect to Pitot readings was carried out in different flow conditions (speed, temperature, gas composition). The results of the two optical measurements are in agreement with each other and fit quite well the theoretical simulation of the flow field, while the results of the Pitot measurements show a remarkable dependence on position and inclination of the Pitot tube with respect to the duct axis. The implications for the metrology of small combustors’ emissions are outlined.

Journal/Review: SENSORS

Volume: 20      Pages from: 7349-1  to: 7349-19

KeyWords: laser flow meter
Pitot tube
flow speed
time of flight
dilution method
flow simulation
flow turbulence
gas sensing applications
DOI: 10.3390/s20247349