جستجوی مقالات مرتبط با کلیدواژه « جابه جایی طبیعی » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

In copper electrodeposition methods, by applying an electric current between two electrodes immersed in an electrolyte containing CuSO4- H2SO4-H2O, copper is deposited on the cathode surface. Presence of magnetic field has a considerable effect on the performance of electrodeposition cells. The most important roles of the magnetic field on these processes are Lorentz force, magnetohydrodynamic (MHD) convection and its interaction with the natural convection induced by the concentration gradient. In this study, an unsteady, two-dimensional copper electrolysis (one phase) and electrowinning (two-phase liquid-gas) cells were simulated in the presence of magnetic field by using Computational Fluid Dynamics (CFD). The equations of Nernst-Planck, momentum and electric potential were solved by finite volume method. The Eulerian-Lagrangian method was used in simulation of two-phase copper electrowinning cell. The simulation results of electrolysis process showed a good agreement in comparison with experimental data of Muhlenhoff et al. After the validation of the model, copper concentration change and velocity profiles of two processes were investigated and compared with each other. The simulation results showed that the MHD interaction with the natural convection and also intrusion layer pile up leads to the velocity decay. As a result, the velocity reduction in the electrowinning process occurs later than in the electrolysis process but its reduction in the second stage of electrowinning process is about 93%, which is much more than 33% in the electrolysis process.

The storage and disposal of greenhouse gases in underground aquifer reservoirs is a suitable option for the reduction of these gases in the atmosphere. Understanding the concepts and mechanisms involved in the storage process such as natural convection and their impact on the amount of time required for storage is very important. Natural convection is an effective mechanism to increase the solubility of carbon dioxide in the storage process. In this study، the injection of carbon dioxide (a major component of greenhouse gases) into aquifer has been studied and numerically simulated. The effect of aquifer salinity on the onset of natural convection phenomena has been studied. To this end، six scenarios revolving around the change of aquifer salt and keeping the other variables involved constant in the process are studied. The results reveal a direct effect of salinity on the activation of natural convection. Increasing aquifer salinity delays the onset of natural convection. As a result، the cumulative amount of gas dissolved after the specified time will be less.