CFD analysis to study the effect of design variables on the particle cut size in hydrocyclones

The modification of hydrocyclone geometry changes the dynamics of the flow, so the particle cut size is affected. Computational fluid dynamics was applied to predict particle classification according to size. Fluent code was used to perform computer simulations for five different hydrocyclone geometries using large eddy simulation and volume of fluid models. The sensitivity to computed modifications in particle classification was evaluated by changing basic design variables, such as spigot diameter, vortex finder diameter, and cone angle. The results show that the particle cut size can be predicted for changes in geometric configuration for a wide range of slurry concentration with a small degree of error using computational fluid dynamics. The error can be attributed to the absence of particle-particle and fluid-particle interaction modeling. However, this assumption is known to be valid only for diluted slurries and some regions within the hydrocyclone. As soon as the particles enter the system, most of them are located within the walls, creating diluted slurry conditions in the main core of the hydrocyclone. The computed results for more concentrated slurries were therefore close to the experimental cut-size values. In all cases, the particle cut size was predicted successfully. Therefore, the evaluation of changes in the standard geometry to manipulate the dynamics and achieve the desired particle cut size becomes possible. (c) 2012 Curtin University of Technology and John Wiley & Sons, Ltd.