Noninvasive liquid level sensing with laser generated ultrasonic waves

Howuk Kim; Bharat Balagopal; Sean Kerrigan; Nicholas Garcia; Mo-Yuen Chow; Mohamed Bourham; Tiegang Fang; Xiaoning Jiang

doi:10.1016/j.ultras.2023.106926

Noninvasive liquid level sensing with laser generated ultrasonic waves

Ultrasonics. 2023 Apr:130:106926. doi: 10.1016/j.ultras.2023.106926. Epub 2023 Jan 18.

Authors

Howuk Kim¹, Bharat Balagopal², Sean Kerrigan³, Nicholas Garcia⁴, Mo-Yuen Chow², Mohamed Bourham³, Tiegang Fang⁴, Xiaoning Jiang⁵

Affiliations

¹ Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA; Department of Mechanical Engineering, Inha University, Incheon 22212, South Korea.
² Department of Electric and Computer Engineering, North Carolina State University, Raleigh, NC 27695, USA.
³ Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695, USA.
⁴ Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA.
⁵ Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA. Electronic address: xjiang5@ncsu.edu.

PMID: 36682290
DOI: 10.1016/j.ultras.2023.106926

Abstract

This article proposes a noninvasive liquid level sensing technique using laser-generated ultrasound waves for nuclear power plant applications. Liquid level sensors play an important role of managing the coolant system safely and stably in the plant structure. Current sensing techniques are mostly intrusive, performing inside the fluidic structure, which is disadvantageous in terms of the regular maintenance of the plant system. Furthermore, typical intrusive sensors do not perform stably under varying environmental conditions such as temperature and radiation. In this study, sensing units are attached to the outer surface of a liquid vessel to capture guided ultrasound waves in a nonintrusive manner. The signal intensity of the guided wave dissipates when the signal interacts with the internal liquid media. The sensing mechanism is mathematically expressed as an index value to correlate the liquid level with the sensor signal. For the acoustic wave generation, laser-generated ultrasound was adopted instead of using typical contact type transducers. Following the simulation validation of the proposed concept, the performance of the developed sensor was confirmed through experimental results under elevated liquid temperature conditions. The nonlinear multivariable regression exhibited the best-fit to the datasets measured under the variable liquid level and temperature conditions.