旋风除尘器下部灰斗内存在的二次流会引起被捕集颗粒重新进入气流，进而导致旋风除尘器除尘效率下降。为有效抑制灰斗内二次流，采用内置防返混锥的手段，对不同防返混锥几何尺寸与安装位置的旋风除尘器进行两相流数值模拟。结果表明，内置防返混锥减少了灰斗内流场的切向、轴向速度及湍流强度，对旋风除尘器灰斗内二次流所引起的颗粒返混现象有显著的抑制作用。模拟结果推荐防返混锥最佳几何尺寸的顶角角度为80°，最佳安装位置为底面与锥口的垂直距离0.375B≤Bs≤0.5B。在入口速度为12 m/s时，与原结构相比，总除尘效率提高11.50%，压降增加8.29%。

The secondary flow effect existing in the hopper of the cyclone caused the captured particles to re-enter the airflow, which decreased the separation efficiency of the cyclone. In order to effectively suppress the secondary flow effect in the hopper, the two-phase flow numerical simulation study of the cyclone with different geometric dimensions and installation positions of the apex cone was carried out by means of built-in apex cone. The results showed that the built-in apex cone reduced the tangential, axial velocity and turbulence intensity of the flow field in the hopper, and had a significant suppression effect on the re-entrainment caused by the secondary flow in the hopper of the cyclone. The simulation results recommend that the optimal angle of the apex cone was 80?, and the best installation position was that the vertical distance between the bottom surface and the cone section was 0.375B≤Bs≤0.5B. When the inlet velocity was 12 m/s, compared with the original structure, the overall separation efficiency was improved by 11.50%, and the pressure drop increased by 8.29%.