Cryogenic Clamp-on Ultrasonic Flowmeters using Single Crystal Piezoelectric Transducers

Clamp-on ultrasound cryogenic flowmeters using single crystal piezoelectric transducers are proposed to enable reliable, accurate cryogenic instrumentation needs in support of NASA Lunar Lander, Ground Operations, Altair, Ares, and Lunar Surface Systems programs. In-space, on the lunar surface, and on the Earth Exploration Systems architecture presents cryogenic storage, distribution, and fluid handling challenges that require new technologies to be developed. Clamp-on ultrasonic flowmeters are proposed because of their advantages such as high turn-down ratio, non-intrusive, no pressure drop, bi-directional measurement, no moving parts and fast response. Single crystal piezoelectrics are attractive because they exhibit 3 to 5 times the strain as conventional piezoelectric ceramics, and retain excellent piezoelectric performance at cryogenic temperatures (< 20 K). Cryogenic piezoelectric transducers with broad bandwidth and high sensitivity will be designed, fabricated and characterized, and cryogenic gas flow rate measurements will be performed using the developed cryogenic transducers. It is expected to have 10-20 dB sensitivity gain (combining transmitting and receiving) for clamp-on ultrasonic flowmeters by using novel single crystal piezoelectric transducers.