SRF Method: Mixing Tank

Description

Mixing tank design with rotating impellers is a core application within rotary equipment and turbomachinery engineering, where accurate modeling of rotational flow behavior directly affects mixing efficiency and process performance. This CFD simulation uses ANSYS Fluent to analyze a closed mixing tank through the Single Reference Frame (SRF) method, a widely used approach for capturing rotational effects in turbomachinery without the computational cost of fully transient rotor motion. The study examines fluid behavior driven by a rotating impeller, with relevance to chemical process engineering, mixing and blending technology, wastewater treatment, and food and beverage processing.

Methodology

The three-dimensional tank geometry is built in ANSYS Design Modeler, and the domain is discretized in ANSYS Meshing using an unstructured grid of 278,775 elements, refined for mesh quality to support accurate results. The SRF method is configured to represent rotational movement within ANSYS Fluent, paired with a steady-state k-ε turbulence model. Boundary conditions are defined for an impeller rotating at 500 rpm, establishing the rotational reference frame used throughout the simulation.

Results Analysis

Post-processing extracts pressure, velocity, and turbulent intensity contours to characterize flow behavior within the rotating system. Pressure distribution analysis reveals variations from the tank center to the walls and their effect on mixing efficiency, while velocity profiles across the tank are correlated with mixing effectiveness. Turbulence intensity patterns are visualized throughout the tank to assess their impact on mixing performance, and vortex formation driven by impeller rotation is examined to understand its influence on overall fluid dynamics. Together, these results support the optimization of mixing tank designs across a range of industrial applications.