The Experimental and Numerical Analysis of a Carbon Dioxide Driven Geothermal Geyser

摘要

This study presents an experimental and numerical investigation of a low temperature CO_2-driven geysering well that discharges an aqueous solution of carbon dioxide. The experimental measurements from the 70m deep geothermal well were performed using vibrating wire piezometers that monitored the pressure and the void fraction at different depths within the well. These results were augmented by thermocouple measurements that showed the well's temperature profile. All of the experimental results show the transient two-phase flow characteristics, normally found in a geysering well. The interpretation of the experimental results was supported by the development of a transient one-dimensional numerical model of the well, which was used to investigate the transport processes. Within this model the mass exchange term between the phases was incorporated by employing separate mass conservation equations for each phase A drift-flux model was also applied to couple the velocities of liquid and gaseous phases. The simulation results show good agreements with the experimental data. Furthermore, the sensitivity analysis of the inflow parameters provides a new insight into the behaviour of geysering flows.