T-Shape Slot CFD Simulation of Water-Sand Multiphase Flow Using ANSYS Fluent

Project Description:

In this project, the water and sand multiphase flow in a T-shape slot is simulated and the results are compared to the experimental data. The aim of the study is to reach similar results. The Eulerian multiphase model is used due to the nature of the problem and 2.5 minutes of the process is considered.

Geometry:

Geometry drawn in Design Modeler software. The T-shape slot configuration, as shown in the following Figure, consisted of a single vertical slot (4 ft in length) with a single “T” intersection placed at 2.5 ft after the fluid entry point from the left. In all slots, the height is 2 ft (height). For all slots, the width of the slots was fixed at 0.215” (inches). An inlet manifold, with six ball valves (inner diameter of each inlet is approximately 0.6”), was attached to the outside of the Plexiglas frame. Only 4 valves were opened for this case.

 Mesh:

After designing the T-shape geometry, it was loaded into ANSYS Meshing software.   There were 235,464 structured cells made, which made a mesh of good quality.

 Methodology:

We used ANSYS Fluent software to solve the governing equations for T-Shape Slot.  For this project, we used a pressure-based solver and a transient method to take into account behavior that changes over time.  The Discrete Phase Model (DPM) was turned on, and an Eulerian model was used for the flow of more than one phase.  The simulation also included the DDPM (Dense Discrete Phase Model) setup.  We chose the k-ε Realizable model to model turbulence.  The materials used were sand and water.  The boundary condition was set as a velocity inlet with an inlet velocity of 10 m/s.

Results:

It took 72 seconds from the beginning of the simulation for water flow to reach its steady condition. Thus, the simulation lasts for 222 seconds or in other words, 2.5 minutes after starting the injection. It needs to be mentioned that the assumption of the wall in the outlet hasn`t been considered so the simulation would have a closer condition to the experimental setup. The velocity contour and the volume fraction of the sand phase on both planes are shown below. As expected, the sedimentation of particles is similar to the experimental data leading us to validated simulation.