Multiphase Flow in Porous Medium, Filter Cake Formation, ANSYS Fluent CFD Simulation Training

Description

Description

The problem simulates multiphase flow in a porous medium using ANSYS Fluent software.

The model is designed in two parts: In the upper part of the column, there are water-soluble particles, and in the lower part of the column, the porous medium is located. Initially, there is a solution with a volume fraction of 0.185 of the particles in the water.

By entering the water flow from the top of the column, applying pressure to the mixture inside the column, and passing through the pores of the porous medium, the soluble particles are separated from the water flow.

The present model is designed in two dimensions using Design Modeler software. The model is designed as a column with a height of 0.08 m and a width of 0.0125 m. The computational area is divided into two parts So that the lower part of the column is related to the porous medium.

Due to the symmetrical structure of the model geometry, only half of the geometry is modeled, and a symmetry boundary condition is used.

We carry out the model’s meshing using ANSYS Meshing software, and the mesh type is structured. The element number is 572852.

Multiphase Flow Methodology

Water flow with a relative pressure of 100,000 pascals and a temperature of 288.15 K enters from the top of a vertical column. It enters a porous medium at the end of the column.

This porous medium is made of aluminum and has a porosity coefficient (ratio of the volume of cavities or fluid space to the total volume) equal to 0.6. Since two phases are mixed in this project, a multiphase flow must be defined.

Therefore, in the present simulation, a multiphase model is used, So that its primary phase is liquid water and its second phase is water-soluble particles (sludge).

The secondary phase is defined as having a density of 2400 kg/m3, a specific heat capacity of 4180 j/kg.K, a thermal conductivity of 0.0454 W/m.K, and a viscosity of It is based on the power law. To define the multiphase model, the Eulerian model is used.

This model is the most complex multiphase software model and can solve a set of momentum and energy equations for each phase separately.

The eulerian multiphase model simulates such things as bubble flows, droplet flows, vertical risers, cyclones, fluidized beds, bubble columns, slurry flows, sedimentation phenomena, and particle suspension phenomena. Also, the simulation is Transient.

Multiphase Flow Conclusion

At the end of the solution process, two-dimensional contours related to the mixture pressure, primary phase velocity, primary phase temperature, primary phase volume fraction, secondary phase velocity, secondary phase temperature, and secondary phase volume fraction are obtained.

The results show that when the water flow inside the column moves downwards, the mixed flow moves towards the porous medium. The behavior of the mixture indicates that the water-soluble particles do not pass through the porous medium and only the water flow passes.

As a result, the soluble particles are separated from the water flow, leading to cake filtration.