An investigation of sonic and ultrasonic flowmeters with transducers in free stream

✍ Scribed by E. Olsen

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 199 KB
• Volume: 2
• Category: Article
• ISSN: 0955-5986
• DOI: 10.1016/0955-5986(91)90031-l

✦ Synopsis

Several different specially designed flowmeters, both in the sonic frequency region, f = 3.1 kHz, and the ultrasonic frequency region, f = 40 kHz, for measuring air velocities were investigated. Special emphasis was given to measurements of very low air velocities, i.e. lower than 1 m s-1. The flowmeters and an anemometer were first run with reference to a pitot-static tube. The accuracy of the output values of the pitot-static tube, however, was rather poor at low air speed. The output values from the ultrasonic flowmeter, the pitot-static tube and the anemometer were then compared with those from a laser-Doppler system. The output values from the pitot-static tube were too high by comparison with those measured by the laser-Doppler system for air velocities less than ca. 0.3 m s-1. The anemometer did not give any values for air velocities lower than ca. 0.06 ms-1. The flowmeter, however, gave quite linear velocity curves down to the lowest measured air velocities.