Fig. 12 shows the particle separation performance for the three
kinds of apex cones. The minimum cut size is obtained for the apex
cone angle of 70°. The 50% cut size decreases as the apex cone angle
increases. The calculation results by use of CFD simulation is also
shown and simulation results agree with the experimental results
qualitatively. The difference between the experimental results and
calculations might be the selection of the flow Reynolds number used
in CFD simulation. To obtain the converged solution, the flow
Reynolds number in CFD simulation selected was 3000. In the
experiment, the flow Reynolds number was greater than 2×104 and
the fluid viscosity effect might be overestimated in the CFD
simulation. It is difficult to obtain the converged solution with flow
Reynolds number greater than 3000. In Fig. 12, the reason of
difference between calculation and experiment might be flow
Reynolds between them. When the solution of high Reynolds number
calculation is obtained, the difference between experiment and
calculation might be small. The results shown in Fig. 12, indicating
high separation performance are obtained for the apex cone angle of
70°, agree with the data shown in Fig. 10.