Investigation of gas-liquid flow hydrodynamics in the industrial-scale stirred tank with inclined impeller

Abstract The inclined-axis stirring system is widely employed in industrial processes due to its exceptional mixing capabilities, ease of industrial retrofitting, and commendable safety and stability features. This study numerically investigates the multiphase flow characteristics within an industrial-scale inclined-axis stirring tank, utilizing the realizable k-ε model and the volume of fluid model. With the validated model, the impact of impeller rotational speed on the flow characteristics in the stirred tank is explored. The findings reveal several noteworthy observations: As the stirring speed increases, liquid level fluctuations intensify. At excessively high stirring speeds, a large number of bubbles are entrained and dispersed into the stirring tank. Multi-scale vortices are observed within the inclined-axis stirred tank. Notably, two relatively large-scale vortices manifest on either side of the rotating blade. Comparatively, the tilted arrangement of the stirring shaft disrupts the symmetry of the flow field. Regions beneath the blades and at the bottom of the stirred tank exhibit elevated liquid phase velocities, radial velocities, and axial velocities. The rising area of the fluid in the stirred tank is near the wall, forming a ring shape, while the center of the ring is characterized by descending fluid. These findings provide valuable theoretical insights for the structural configuration and considerations related to energy conservation in industrial agitation equipment.