Experimental investigations of Pool hydrodynamics and aerosol removal under low momentum injection

A detailed experimental database was generated from hydrodynamic characterization a Wire Mesh Sensor (WMS) and a High-Speed Camera (HSC) in the TRISTAN facility and aerosol retention measurements in the SAAB facility, performed under identical injection conditions in the low-momentum globule regime. Nitrogen was injected through 5 mm and 10 mm nozzles, spanning a flow range of 1–10 l n /min, with a water submergence of 300 mm. This corresponds to a Weber number up to 7.3. HSC images showed aperiodic globule formation, revealing intensified bubble coalescence and break-up with increasing flow rates. The image processing demonstrated a high Gas Void Fraction (GVF) in the injection region, which increases with flow rate. The WMS data were collected at heights of 40, 100, and 200 mm above the nozzle tip. The data analysis mirrored GVF trends from the HSC images. Furthermore, the velocity profile of the gas phase was analyzed. Notably, the impact of the nozzle diameter is prominent in the injection region near the nozzle. An advanced algorithm was developed to track and extract globule formation characteristics from HSC images. A new scaling concept to describe globule characteristics as function of the Weber number was introduced and validated using additional experimental data. Based on this, a new correlation for the globule diameter is proposed for Weber number up to 70. Corresponding aerosol pool scrubbing tests were conducted and showed that particle retention is roughly insensitive to the gas flow rate within the experimental range, but is enhanced as particle inertia increases. In addition, use of the smaller nozzle under similar flow rates results mostly in a slight improvement of aerosol removal. These high-fidelity data can serve to develop and validate CFD models for hydrodynamics and aerosol pool scrubbing. • Experiments on bubble hydrodynamics and aerosol retention in aperiodic globule regime. • Nozzle effect is most pronounced in the injection region near the nozzle. • New concept introduced to describe globule characteristics at detachment. • New correlation proposed for globule diameter up to We = 70. • Aerosol retention is weakly flow-dependent but increases with particle size.