(562d) Modeling of Moving Bed Granular Filtration Using Eulerian-Eulerian Approach

Ravi Kolakaluri

Software Electronics and Mechanical Systems

 3M Corporate R&D

Granular filtration is traditionally used for water treatment, but due to the ease of its usage it is also widely used in chemical industries. Granular filtration is mostly used to treat flue gas, combustion products, polymers and petrochemical products. The common process of conducting granular filtration is in the fixed-bed mode, but it can also be conducted in a moving-bed or fluidized-bed mode so that the operation can be carried out continuously.

Granular filtration consists of two solid phases and fluid phase. The first of the solid phases comprises the granules through which the fluid flows, and the other solid phase consists of fine particles that are suspended in the fluid phase. Direct numerical simulation of a full-scale granular bed is prohibitively expensive in terms of the required computational resources. This is due to the range of length and time scales that need to be simulated, hence the Eulerian-Eulerian two-fluid approach is a viable approach to model a full-scale granular bed.

In this study, we develop a computational fluid dynamics (CFD) model where the granules and fluid phase are modeled using an Euler-Euler two-fluid model and the fine particles that are suspended in the fluid phase are simulated using two User-Defined-Scalars (UDS). One of the UDS represents the number density of particles suspended in the fluid phase and the particle velocity in this UDS is obtained from fluid velocity using the equilibrium Eulerian model suggested by Ferry and Balachandar (2001). The other UDS is for number density of particles deposited on the granules, which are moving with the granules. The validation of the CFD modeling results are done using the experiments.