Large-eddy simulation of double-plume formation induced by CO2 dissolution in the ocean

Abstract

Using two-fluid LES technology, a numerical model is developed to simulate double-plume formation under conditions relevant to CO2 ocean sequestration applications. A small-scale ocean turbulent flow is created and maintained by a forced-dissipative mechanism and LES. Data on ocean currents, temperature and salinity were employed by the model as inlet boundary and initial conditions, respectively. A set of empirical formulae, calibrated with laboratory experimental data, was developed to describe momentum, mass and heat transfer phenomena. Using this model, the influence of the initial diameter of CO2 droplets released in the deep ocean and thermal effects on the structure of two plumes were investigated. The height of the CO2 droplet plume and the local minimum pH within the CO2-enriched seawater plume were found to be very sensitive to the initial diameter of injected CO2 droplets. Plume height and pH are two key parameters to assess CO2 sequestration efficiency and related biological impacts. Thermal effects associated with CO2 dissolution appeared to have limited influence on CO2-enriched seawater plume structure and pH, but can significantly affect the LCO2 plume and the temperature field near the CO2 injection nozzle.