Influence of Rayleigh-Taylor Instability on Impurity Dynamics during Column Back-Flushing Filtration

During the manufacturing or processing of materials, large volumes of water of the required quality are often needed. Industrial water treatment and water purification is the process of removing impurities and pollution from the considered medium. To obtain liquid with specified quality parameters, complex systems of filters and treatment facilities are generally used. In this work, the cleaning process for a filtration column is studied. Three-dimensional numerical simulations of flow in a columnar array consisting of a porous medium are conducted. In particular, a model case corresponding to laboratory conditions is examined, with potassium salt being considered as a pollutant. It is assumed that the vertical column is a desalination system, as a result of which saturation and clogging of the pores of the medium occur; at the end of the operating cycle of such a filter, washing is required. Filtration modeling is implemented through the Brinkman approach taking into account density stratification. It is found that owing to density stratification and related effects, clean water moves in the central part of the filter, while contaminants near the side walls remain motionless for a long time. A solution to this problem is presented by changing the flow rate of supplied water.