Experimental study of pool scrubbing with respect to gas injection flow rate and velocity, and pool scrubbing model development

Abstract

In this dissertation, experimental studies were conducted to understand the characteristics of submerged gas jet with respect to injection gas flow rate, and model was proposed to predict the aerosol removal efficiency by pool scrubbing under high-speed gas injection conditions. To understand the behavior of the submerged gas jet with respect to the injection gas flow rate, the centerline velocity and velocity decay rate of the jet were measured using a pitot tube. Visualization experiments were also performed to measure the gas behavior and jet expansion angle and spreading rate with injection gas flow rate using high-speed camera. For the experiment aimed at measuring the void fraction inside the submerged gas jet, a optical fiber probe was used. In addition to these experiments, aerosol removal experiments were conducted based on the injection flow rate and nozzle size. The experimental results showed that as the injection flow rate increased, the aerosol removal efficiency also increased. Furthermore, it was observed that the aerosol removal efficiency increased as the size of the nozzle decreased. The experimental data, including gas velocity and void fraction, which were used to understand the gas behavior, were used to validate the behavior model of the submerged gas jet. Additionally, a aerosol removal model, considering aerosol removal by droplet was developed for the removal of aerosols in the submerged gas jet. By utilizing the developed model to simulate the experiments conducted at KAIST and KAERI, the average relative error was approximately 62%. Furthermore, when comparing the simulated results to the jet scrubbing experimental results proposed by Herranz, the average relative error was about 21%. These results indicate a higher analytical performance compared to model that assume bubbly flow.