A New Model for Measurement of the Droplet Size and Volume Fraction in Air–Droplet Two-Phase Flow Based on Ultrasonic Attenuation Method

Abstract

Ultrasonic attenuation method has great advantages in the measurement of particle two-phase flow. Most of the existing ultrasonic attenuation theoretical models are suitable for the two-phase flow where the continuous phase is liquid or the particle phase is solid, and different models are aimed at the different particle size range, which makes them limited in practical applications. To solve the above problems, a new ultrasonic attenuation theoretical model, which combines McClements model and Bouguer–Lambert–Beer-Law (BLBL) model (MCBL model), is proposed for air–droplet two-phase flow. It extends the droplet size range to make it not affected by frequency and suitable for all wavelength regimes. In addition, the ultrasonic propagation process in air–droplet two-phase flow is simulated based on COMSOL. The simulation ultrasonic attenuation results are compared with the existing theoretical models and MCBL model. Besides, the simulation ultrasonic attenuation results are inversed by the MCBL model and hybrid particle swarm optimization (HPSO) algorithm, and the error is within ±8%. Furthermore, the flowing experiment is carried out to measure the ultrasonic attenuation coefficient of air–droplet two-phase flow. The experimental results are also inverted using the proposed MCBL model and HPSO algorithm to obtain the droplet size and volume fraction. Compared with the results of the image method, the error is less than 15%, which verifies the applicability and practicability of the MCBL model proposed in this article.