Moving Mesh: Mixing Tank, Mesh Motion Method

Mixing Tank CFD Simulation Using Mesh Motion Method in ANSYS Fluent

Introduction

This project simulates the performance of a mixing tank using ANSYS Fluent. The closed tank contains water, and an impeller rotates at 500 rev/min, generating a substantial vortex at the center of the tank. This product represents the fourth episode of the Turbomachinery Training Course.

Geometry and Mesh

The three-dimensional geometry of the mixing tank was designed in Design Modeler and meshed using ANSYS Meshing, resulting in an unstructured mesh with 209,328 elements.

Methodology

The Mesh Motion method was enabled to capture the rotational movement of the impeller. This approach requires two distinct zones connected through an interface: a rotating zone containing the impeller, which moves independently, and a surrounding stationary zone. The simulation was solved as unsteady, with the k-epsilon model selected to capture the turbulent behavior of the flow.

Results and Conclusion

Two-dimensional contours of pressure, velocity, and turbulent intensity were obtained to characterize the flow field within the tank. The pressure contours show that water pressure in front of the impeller is considerably higher than behind it, consistent with the impeller's driving action on the fluid. As expected, flow velocity behind the impeller exceeds that observed elsewhere in the domain, while the turbulent intensity contours reveal the extent of turbulence generated throughout the tank as a result of the impeller's rotational motion.