Computational fluid dynamics analysis of a novel axial flow hydrocyclone

A comparative CFD investigation was carried out for a mini axial, a large axial and a large reverse flow hydrocyclone. The diameters selected were 5 mm and 75 mm for the mini and large hydrocyclones, respectively. The simulations were conducted using a large eddy simulation (LES) turbulence model with various subgrid scale models, and the results of the reverse flow hydrocyclone were validated against published LDV data. The numerical results confirmed that the LES-Smagorinsky model provides good prediction relative to the other subgrid scale models studied, giving an error percentage of 0.45% for the water split ratio. Numerical investigation of mini axial and reverse flow hydrocyclones were performed. The Lagrangian discrete phase model (DPM) was used to track the soda-lime glass particles released from the inlet surface. The soda-lime glass particles had a density of 2520 kg/m3 with a particle diameter range of 10 µm to 150 µm. The results indicate that the axial flow hydrocyclone gave a lower pressure drop and a higher cut size than the reverse flow hydrocyclone for inlet velocities ranging from 1-10 m/s. Thus, the axial flow hydrocyclone is an effective particle separator. The effect of inlet dimensions, vortex finder diameter and length on the performance and flow pattern was then investigated. Thirteen mini axial hydrocyclones separators were investigated for a fixed inlet velocity of 2 m/s. The simulations showed that changing the vortex finder diameter and length had a more pronounced effect on the separation efficiency and velocity profiles than changing the inlet dimensions. Decreasing the diameter of vortex finder translates to higher separation efficiency at the cost of higher pressure drop. The results showed that lengthening the vortex finder increases the separation efficiency but decreases the cut size as the vortex strength decreases with vortex finder length. The axial flow hydrocyclone can be a serious competitor to the reverse flow hydrocyclone for industrial use. A comprehensive study of 75 mm axial flow hydrocyclone enormously improved the understanding of the possibility of its use for industrial applications. A comparison of the axial and reverse flow hydrocyclones of 75 mm diameter showed that the cut size of the axial flow hydrocyclone was larger than the reverse flow hydrocyclone at particle concentrations of 4.88% and 10.47%. However, the pressure drop was significantly lower for axial flow hydrocyclone. The CFD-based investigation showed that the axial flow hydrocyclone could be successfully used to classify particles in the industry with a substantially lower pressure drop and pumping energy requirement