Numerical Simulation Of Two-Phase Flow In Inclined Settlers And Their Separation Performance

Inclined settlers have been widely used in chemical, mineral, and environment protection industries to recycle waste water for many years. Despite the simplicity of their construction, the behavior of internal fluid dynamics is very complex. Based on much predefinition, geometry and operational parameters are calculated through experiment and experience equations. The limitation of this conventional design method is more and more evident.In order to overcome the shortcomings of the traditional design method, the author has carried out some work on the fundamental two-phase flow behavior, using mathematical model to investigate the phenomenon of separation process and the genera] fluid behavior. The aim is to provide a model for the two-phase flow and to establish a calculating method. By comparing Single Particle Dynamics Model (SPD), Small Slide Model (SS), No Slide Model (NS), Particle Trade Model (PT) and Multi-Flow Model (MF), we select SPD model to simulate the flow within inclined settlers.The computer code adopted in this paper has good structure and is easy to debug. A steady two-phase flow is simulated and analyzed. The mesh used in the code is signed by Finite Control Volume method. Power Law Difference Scheme(PLDS) used in the calculation not only is simple but also has high precision. Furthermore, the choice of employing more efficient algorithm (SIMPLER) for forming a linkHibetween velocity and pressure leads to the fast rates of convergence.The flow fields of inclined settlers are obtained through the numerical simulation and analyzed in a graphic way. It's found that the calculation result is different from the conventional prediction. After the velocity distribution is given, the settling characteristic of inclined settlers, such as cut size, can be calculated. Validity of the calculation is proved by comparing the results with the experimental data.It's found that the liquid flow of inclined settlers has a great effect on particle settlement except the settling enhancement by inclined plates. Downward flow below the inlet could bring particle down quickly and is helpful to particle settlement.This paper has discussed the mathematical model of two-phase flow in inclined settlers and achieved satisfactory development in numerical simulation. The calculation results are better than those from the correlations based on the experimental and have great significance to engineering design and optimization of inclined settlers.