Mixing Tank with Helical Impeller CFD Simulation, ANSYS Fluent Tutorial

Description

This project simulated a mixing tank with a helical impeller using the sliding mesh option.

The closed mixing tank contains water liquid while the helical impeller starts rotating with 200 rpm angular velocity and creates a massive vortex in the middle of the tank.

The 3D geometry was created in Design Modeler software. A helical blade is located at the top of a mixing tank. In addition, an unstructured mesh grid was carried out using ANSYS Meshing software, and overall, 1,442,934 elements were generated. Still, After hiring Ansys Fluent software’s “Make Polyhedral “capability, the number of elements has reached 296,106.

Methodology: Mixing Tank with Helical Impeller

The simulation is Transient(unsteady) in order to capture the behavior of fluid over time. The Pressure-based solver type is used due to the incompressibility of the working fluid. The gravitational acceleration effects are considered by defining 9.81 m/s^2 in the negative direction of Y. Also, the Mesh Motion option is enabled to model the rotational motion of the impeller.

Conclusion

The cylindrical mixing tank is full of water liquid, while the helical impeller rotates with 200rpm angular velocity. The rotational motion creates a massive vortex in the middle of the tank and increases the mixing rate.

The streamlines which can be seen in the figures above, show the mentioned vortex clearly. Furthermore, the velocity is higher around helical blades, and a reduced pressure zone is shown in contours.