In order to improve the asymmetry of flow field and the separation efficiency of cyclone separator

a method to set necking angle on upper side of the inlet of the cyclone separator was proposed. The Reynolds stress model(RSM) provided by Fluent software was employed to simulate the cyclone separator with the necking angle on the upper side of the inlet. The results indicate that

the necking angle on upper side of the inlet makes the static pressure in the near wall area of the cyclone separator increase obviously

the static pressure fluctuation on the axis decrease gradually

and the negative pressure value near the dust exhaust port become larger

which is beneficial to improving the phenomenon of particle back-mixing. The inlet necking angle makes the inlet cross section gradually be smaller

so the inlet airflow gradually accelerates

and the pressure drop is roughly proportional to the square of the inlet velocity

resulting in a gradual increase in pressure drop. The inlet necking angle does not change the area where the short circuit flow occurs

and the integrated cross-section is 15 mm below the end of the vortex finder

but the improved cyclone separator has a reduced short circuit flow and a larger tangential velocity

which is conducive to particle separation.