Numerical modelling of turbulent particle-laden sonic CO2 jets with experimental validation

Under-expanded particle-laden flows resulting in velocities greater than the local speed of sound are a feature of a wide number of applications in aviatic, astronautical, and process engineering scenarios including those relating to the accidental release of high-pressure fluids from reservoirs or pipelines. Such pipelines are considered to be the most likely method for transportation of captured carbon dioxide (CO2) from power plants and other industries prior to subsequent storage in carbon capture and storage (CCS) applications. Their safe operation is of paramount importance as their contents are likely to be in the region of several thousand tonnes. CO2 poses a number of dangers upon release due to its physical properties. It is a colourless and odourless asphyxiant which has a tendency to sublimation and solid formation, and is directly toxic if inhaled in air at concentrations around 5%, and likely to be fatal at concentrations around 10%. The developments presented in this paper concern the formulation of a multi-phase homogeneous discharge and dispersion model capable of predicting the near-field fluid dynamic, phase and particle behaviour of such CO2 releases, with validation against measurements of laboratory-scale jet releases of CO2 recently obtained by our group.