Numerical simulation of supercritical carbon dioxide jet at well bottom

A numerical model was developed to study the flow field characteristics of supercritical CO2 (SC-CO2) impacting jet at well bottom. The model took account of jet hydrodynamics, mass transfer and thermodynamic properties of SC-CO2. Formulas of the density, viscosity and thermal conductivity of CO2 were verified for a supercritical state, and they were embedded in a CFD model through the user defined function (UDF). Complex coupling was achieved with the modified SIMPLE segmentation algorithm, and fields of the SC-CO2 impact flow, pressure, temperature and physical parameters were obtained. The reliability of the numerical model was validated in experiments that monitored the pressure and temperature of SC-CO2 impacting jet using sensors. The laboratory experiments show that the model accurately predicts the temperature and pressure fields of SC-CO2 impacting jet. SC-CO2 impacting jet has a more obvious thermal effect on the wall without any phenomena of CO2 freezing and blocking nozzle. The jet flow field can be divided into five areas according to flow characteristics, and the CO2 phase state in flow field is analyzed. The established calculation method and findings reported in the paper will provide guidance for engineering applications.