Mixer: Powder Distribution, Transient Solver

Powder Distribution in Mixer, Transient CFD Simulation

Description

This project simulates powder distribution within a stationary fluid inside a mixer tank. Powder initially settles at the bottom of the tank, after which the mixer propeller begins rotating to disperse it throughout the surrounding fluid. Given the high computational cost of this simulation, it was run only for a limited time window.

The mixing tank geometry was designed in SpaceClaim and meshed in ANSYS Meshing, generating approximately 3,000,000 cells.

Methodology

The working fluids — powder and liquid water — were modeled using the Eulerian multiphase model, with the powder treated as the secondary phase using the granular option to capture its particulate, granular nature. Propeller rotation was captured using mesh motion, with the propeller rotating at 30 rpm.

Conclusion

Results reveal a clear pattern of powder distribution within the fluid after a set period of mixing. The powder appears distinctly layered, with the highest concentration settled at the bottom of the container, transitioning through a thin, powder-rich boundary layer just above this region — indicating the powder is distributed in a gradient rather than uniformly.

This pattern confirms that, within the limited mixing time simulated, the powder has not yet been evenly dispersed throughout the fluid — an expected outcome given the mixer's short operating duration. The results also show that the central shaft and impeller visibly influence local flow patterns and powder distribution in their immediate vicinity, highlighting their role in shaping the overall mixing behavior even at this early stage.